Causal Role of Delta-beta Coupling for Goal-directed Behavior in Anhedonia
Phase: NA
Conditions: Major Depressive Disorder, Anhedonia
Sponsor: University of North Carolina, Chapel Hill

Causal role of delta-beta coupling for goal-directed 
behavior in anhedonia 
Protocol Number: 21-1321 
Principal Investigator: Flavio Frohlich, PhD 
Co-Investigator: David Rubinow, PhD 
Co-Investigator: Crystal Schiller, PhD 
Study Coordinator: Justin Riddle, PhD 
Funded by: Foundation of Hope, National Institute of Mental Health 
Version Number:  V2 
15 September 2021 
 
 
Summary of Changes from Previous Version: 
Version 
Control 
Affected 
Section(s) 
Summary of Revisions Made 
Rationale 
Version 1.2 
May 13, 
2021 
Sections 1, 5, 
8, 9 
Added exploratory analysis, explained 
each metric in greater detail, addressed 
statistical feedback, fixed terminology. 
Incorporated SRC feedback 
Version 2 
Sept 15, 
2021 
Section 1, 4, 
5, 6, 7, 8, 9 
Included new funding source: K99/R00 
from NIMH awarded to JR. Removed 
hormone sampling. Updated screening 
procedure. Removed the probabilistic 
reward task. Split the first session into 
two session. Updated exclusion criteria. 
New funding source is required for 
consent form. Hormone sampling was 
deemed to be not feasible. Screening 
procedure updated to reduce 
experimenter burden regarding 
suicide risk. Not sufficient baseline 
data for probabilistic reward task. Part 
1 and 2 of session 1 are now separate. 
Further clarification on exclusion 
based on substance/alcohol use 
disorder. 
NCT05084924

  
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STATEMENT OF COMPLIANCE ............................................................................................................................. 1 
1. PROTOCOL SUMMARY ....................................................................................................................................... 2 
1.1 Synopsis ............................................................................................................................................................. 2 
1.2 Schema .............................................................................................................................................................. 4 
1.3 Schedule of Activities (SoA) ............................................................................................................................ 5 
2. INTRODUCTION ..................................................................................................................................................... 6 
2.1 Study Rationale ................................................................................................................................................. 6 
2.2 Background ........................................................................................................................................................ 6 
2.3 Risk/Benefit Assessment ................................................................................................................................. 7 
2.3.1 Known Potential Risks 7 
2.3.2 Known Potential Benefits ..........................................................................................................................8 
2.3.3 Assessment of Potential Risks and Benefits .........................................................................................9 
3. Objective and Outcome Measures ....................................................................................................................... 9 
4. STUDY DESIGN ................................................................................................................................................... 10 
4.1 Overall Design ................................................................................................................................................. 10 
4.2 Scientific Rationale for Study Design .......................................................................................................... 12 
4.3 Justification for Dose ...................................................................................................................................... 12 
4.4 End of Study Definition .................................................................................................................................. 13 
5. STUDY POPULATION ......................................................................................................................................... 13 
5.1 Inclusion Criteria ............................................................................................................................................. 13 
5.2 Exclusion Criteria ............................................................................................................................................ 14 
5.3 Lifestyle Considerations ................................................................................................................................. 15 
5.4 Screen Failures ............................................................................................................................................... 15 
5.5 Strategies for Recruitment and Retention................................................................................................... 15 
6. STUDY INTERVENTION ..................................................................................................................................... 16 
6.1 Study Intervention(s) Administration ............................................................................................................ 16 
6.1.1 Study Intervention Description .............................................................................................................. 16 
6.1.2 Dosing and Administration ..................................................................................................................... 17 
6.3 Measures to Minimize Bias: Randomization and Blinding ....................................................................... 17 
6.4 Study Intervention Compliance ..................................................................................................................... 18 
6.5 Concomitant Therapy ..................................................................................................................................... 18 
   6.5.1 Rescue Medicine 
18 
7. STUDY INTERVENTION DISCONTINUATION AND PARTICIPANT 
DISCONTINUATION/WITHDRAWAL .................................................................................................................... 19 
7.1 Discontinuation of Study Intervention .......................................................................................................... 19 
7.2 Participant Discontinuation/Withdrawal from the Study ............................................................................ 19 
7.3 Lost to Follow-Up ............................................................................................................................................ 19 
8. STUDY ASSESSMENTS AND PROCEDURES .............................................................................................. 20 
8.1 Efficacy Assessments .................................................................................................................................... 20 
8.1.1 
Physiological Changes 
17 
8.1.2 
Clinical Evaluations 
20 
8.1.3 
Self-Report Assessments 
21 
8.2 Safety and Other Assessments .................................................................................................................... 21 
8.3 Adverse Events and Serious Adverse Events ........................................................................................... 22 
8.3.1 Definition of Adverse Events (AE) ........................................................................................................ 22 
8.3.2 Definition of Serious Adverse Events (SAE) ....................................................................................... 22 

  
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8.3.3 Classification of an Adverse Event ....................................................................................................... 22 
8.3.4 Time Period and Frequency for Event Assessment and Follow-Up ............................................... 24 
8.3.5 Adverse Event Reporting ....................................................................................................................... 25 
8.3.6 Reporting of Pregnancy.......................................................................................................................... 25 
8.4 Unanticipated Problems ................................................................................................................................. 25 
8.4.1 Definition of Unanticipated Problems (UP).......................................................................................... 25 
8.4.2 Unanticipated Problem Reporting ......................................................................................................... 26 
8.4.3 Reporting Unanticipated Problems to Participants ............................................................................ 26 
9. STATISTICAL CONSIDERATIONS ................................................................................................................... 26 
9.1 Statistical Hypotheses .................................................................................................................................... 26 
9.2 Sample Size Determination ........................................................................................................................... 27 
9.3 Populations for Analyses ............................................................................................................................... 29 
9.4 Statistical Analyses ......................................................................................................................................... 30 
9.4.1 General Approach 
30 
9.4.2 Analysis of the Primary Efficacy Endpoint(s) (EEG) .......................................................................... 30 
9.4.3 Analysis of the Secondary Endpoint(s)(Correlation between EEG Changes and Symptoms of 
Depression) 
31 
9.4.4 Safety Analyses 
31 
9.4.5 Baseline Descriptive Statistics .............................................................................................................. 32 
9.4.6 Planned Interim Analyses ...................................................................................................................... 32 
9.4.7 Sub-Group Analyses 
33 
10 SUPPORTING DOCUMENTATION AND OPERATIONAL CONSIDERATIONS ..................................... 33 
10.1 Regulatory, Ethical, and Study Oversight Considerations ..................................................................... 33 
10.1.1 Informed Consent Process .................................................................................................................. 33 
10.1.2 Study Discontinuation and Closure .................................................................................................... 34 
10.1.3 Confidentiality and Privacy .................................................................................................................. 34 
10.1.4 Future Use of Stored Specimens and Data ...................................................................................... 34 
10.1.5 Key Roles and Study Governance ..................................................................................................... 35 
10.1.6 Safety Oversight 
35 
10.1.7 Clinical Monitoring 
35 
10.1.8 Quality Assurance and Quality Control.............................................................................................. 36 
10.1.9 
Data Handling and Record Keeping ........................................................................... 36 
10.1.10 
Protocol Deviations 
37 
10.1.11 
Publication and Data Sharing Policy ........................................................................... 37 
10.1.12 
Conflict of Interest Policy .............................................................................................. 37 
10.2 
Additional Considerations ................................................................................................................. 37 
10.3 
Abbreviations ...................................................................................................................................... 38 
10.4 
Protocol Amendment History ........................................................................................................... 40 
11 
REFERENCES .............................................................................................................................................. 41 
 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
15 Sept 2021 
 
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STATEMENT OF COMPLIANCE 
 
The trial will be carried out in accordance with International Conference on Harmonisation Good Clinical 
Practice (ICH GCP) and the following:    
 
x 
United States (US) Code of Federal Regulations (CFR) applicable to clinical studies (45 CFR Part 
46, 21 CFR Part 50, 21 CFR Part 56, 21 CFR Part 312, and/or 21 CFR Part 812)  
 
National Institutes of Health (NIH)-funded investigators and clinical trial site staff who are responsible 
for the conduct, management, or oversight of NIH-funded clinical trials have completed Human Subjects 
Protection and ICH GCP Training.  
 
The protocol, informed consent form(s), recruitment materials, and all participant materials will be 
submitted to the Institutional Review Board (IRB) for review and approval.  Approval of both the 
protocol and the consent form must be obtained before any participant is enrolled.  Any amendment to 
the protocol will require review and approval by the IRB before the changes are implemented to the 
study.  In addition, all changes to the consent form will be IRB-approved; a determination will be made 
regarding whether a new consent needs to be obtained from participants who provided consent, using a 
previously approved consent form. 
 
 

Causal role of delta-beta coupling in anhedonia 
 
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Protocol: 21-1321 
 
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1. PROTOCOL SUMMARY 
1.1 SYNOPSIS  
Title: 
Causal role of delta-beta coupling for goal-directed behavior in anhedonia 
Study Description: 
The purpose of this clinical trial is to investigate the causal role that delta-
beta coupling plays in goal-directed behavior in participants with major 
depressive disorder (MDD) and symptoms of anhedonia. The participants 
will perform a reward-based decision-making task. During the task, cross-
frequency transcranial alternating current stimulation (tACS) will be 
delivered at delta-beta frequency, a control-frequency, or an active sham. 
Electroencephalography will be collected in intermittent resting-state 
periods. Structural and functional magnetic resonance imaging (MRI) will 
be collected during the resting-state and during performance of the 
reward-based decision-making task. 
Objectives: 
 
Primary Objective: To investigate whether delta-beta tACS will produce an 
increase in goal-directed behavior during reward-based decision-making. 
Secondary Objective: To investigate whether delta-beta tACS will result in 
a lasting increase in delta-beta coupling during eyes-open resting-state 
recorded immediately following stimulation. 
  
Outcomes: 
Primary Outcome: Behavioral metric, percentage of hard trials chosen, 
during the Expenditure of Effort for Reward Task (EEfRT). 
Secondary Outcome: Neural metric, degree of phase-amplitude coupling 
between prefrontal delta oscillations and left motor beta oscillations, 
quantified during eyes-open resting-state recorded post-stimulation 
intermittent with task blocks. 
Study Population: 
We will recruit men and non-pregnant women ages 18-65 with a diagnosis 
of non-psychotic MDD, free of benzodiazepines and anticonvulsant 
medications. Eligible participants will be stratified based on anhedonia 
À]˙µZZæì9}(]]v^Z]PZ_vZ
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Participants must also have less than 3 on the Suicide 
Item on the Hamilton Depression Rating Scale (HAM-D) and low suicide 
risk determined as having no active intent as determined by the Columbia 
Suicide Severity Rating Scale (C-SSRS). Participants must also be eligible to 
receive tACS and MRI. Participants will be recruited from the Chapel Hill, 
Durham and Raleigh areas. 
Phase: 
N/A 
Description of 
Sites/Facilities Enrolling 
Participants: 
University of North Carolina at Chapel Hill 
 
 
Description of Study 
Intervention: 
We will use the NEUROCONN DC Stimulator Plus for investigational 
purposes to deliver either cross-frequency delta-beta, cross-frequency 
theta-gamma, or active sham transcranial alternating current stimulation.  
Active sham treatment will include 20 seconds of ramp in to 40 seconds of 
tACS with a ramp out of 20 seconds for a total of 80 seconds of 
stimulation. The choice of an active sham is motivated to enhance success 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
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of participant blinding by mimicking skin sensations associated with tACS. 
Theta-gamma and delta-beta tACS will also have a 20 second ramp in and 
ramp out for each task block. With 8 total task blocks each lasting 5 
minutes, participants receive a total of 40 minutes of stimulation. 
Stimulation waveform is a low-frequency sine wave with a superimposed 
high-frequency sine-wave at the peak of each cycle. The zero-to-peak 
amplitude of stimulation is 2mA.  
Study Duration: 
2 years 
Participant Duration: 
Participation for each participant will be 2 weeks. Completion includes 
three sessions: a clinical assessments session, a stimulation session, and an 
MRI session. The clinical assessments session will take approximately 2 
hours. The stimulation session will take approximately 3 hours. The visit to 
the MRI takes approximately 1.5 hour. We estimate that total participation 
to be approximately 6.5 hours. 
 
 

Causal role of delta-beta coupling in anhedonia 
 
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1.2 SCHEMA 
 
Figure 1. Experimental design depicted as a flow-chart. 
 
1.3 SCHEDULE OF ACTIVITIES (SOA) 
 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
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Procedures 
Phone Screening 
Online Assessments 
Session 1 Clinical 
Assessments 
Session 2 - 
Stimulation 
Session 3 - MRI 
Informed consent 
X (verbal) 
X (digital) 
X (written) 
 
 
Determine Eligibility 
X 
X 
X 
 
 
PHQ-8 (without suicide q.) 
 
X 
 
 
 
PHQ-9 
 
 
X 
 
 
SHAPS 
 
X 
X 
X 
 
Demographics 
 
 
X 
 
 
Medical history 
 
 
X 
 
 
MINI (diagnostic) 
 
 
X 
 
 
C-SSRS 
 
 
X 
 
 
Maudsley Staging Method 
 
 
X 
 
 
HAM-D 
 
 
X 
 
 
RRS 
 
 
X 
 
 
BIS/BAS 
 
 
X 
 
 
SHAPS 
 
 
X 
 
 
C-SSRS 
 
 
X 
 
 
TEPS 
 
 
X 
 
 
Beck Depression Inventory - II 
 
 
X 
 
 
BAS/BIS 
 
 
X 
 
 
STAI 
 
 
X 
 
 
Urine Pregnancy Test 
 
 
 
X 
 
Randomization 
 
 
 
X 
 
Resting-state EEG 
 
 
 
X 
 
EEfRT 
 
 
 
X 
 
EEfRT with tACS 
 
 
 
X 
 
Intermittent resting-state EEG 
 
 
 
X 
 
Stimulation Questionnaire 
 
 
 
X 
 
AE Structured Interview 
 
 
 
X 
 
AE Review and Evaluation 
 
 
 
* 
 
Structural MRI 
 
 
 
 
X 
Resting-state MRI 
 
 
 
 
X 
Functional MRI with EEfRT 
 
 
 
 
X 
* when applicable 
 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
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2. INTRODUCTION 
 
2.1 STUDY RATIONALE  
 
Anhedonia, the inability to seek-out and experience pleasure, remains difficult to treat, with many pharmacological 
interventions occasionally increasing, or introducing, anhedonia (Treadway and Zald 2011, Husain and Roiser 2018, 
Lambert, Da Silva et al. 2018). Many proven treatments in psychiatry are less effective in patients with elevated 
symptoms of anhedonia (Nierenberg, Keefe et al. 1999, Shelton and Tomarken 2001, Landén, Högberg et al. 2005, 
Hatzigiakoumis, Martinotti et al. 2011, McMakin, Olino et al. 2012). In affective disorders such as major depressive 
disorder (MDD), anhedonia is positively correlated with suicidal behavior (Bonanni, Gualtieri et al. 2019). Therefore, 
effective treatment for anhedonia is a critical factor in the ongoing mental health crisis. Symptoms of anhedonia fall 
`]Z]vZ^W}]]Àsov^˙u_}(Z
earch domain criteria (RDoC) framework (Nusslock and Alloy 2017) 
v}u]`}]u˙}u}vvW^o]l]vP_v^`v]vP_
(Gard, Gard et al. 2006, Kring and Barch 2014). The 
^o]l]vPU_ } }vµuu}˙U }u}vv (o
ects the experience of rewards as pleasurable. Collectively, reward 
evaluation is known to critically rely on the orbitofrontal cortex of the medial prefrontal cortex (mPFC) to process 
the value of the reward ~K[}Z˙îììðUW}
-Schioppa and Cai 2011) and the nucleus accumbens of the ventral 
striatum (vSTR) to evaluate the effortful cost (Sugam, Day et al. 2012). Correlational studies find reduced activation 
and decreased functional connectivity in mPFC-vSTR during reward-based decision-making tasks in patients with 
anhedonia (Epstein, Pan et al. 2006, Wacker, Dillon et al. 2009, Greenberg, Chase et al. 2015). The second component 
]Z^`v]vPU_}v]]}˙U}u}vvZ(oZ}Pv]Ì]}v}(ZÀ]}
-benefit 
computation t goal-directed behavior. The dorsal striatum (dSTR) processes the anticipation of receiving a future 
reward and orients behavior towards reward-seeking (Pizzagalli, Holmes et al. 2009, Zhang, Lin et al. 2016). The dSTR 
(caudate and putamen) is guided by the dorsolateral prefrontal cortex (dlPFC; middle frontal gyrus) and together 
they play a critical role in planning and initiating goal-directed behavior (Badre and Nee 2018). Lesion to the dlPFC 
results in deficits in planning and initiating goal-directed behavior (Szczepanski and Knight 2014) and lesion to dSTR 
results in apathy and similar deficits as lesions to dlPFC (Mendez, Adams et al. 1989). Thus, the neuropsychological 
etiology of anhedonia presents two candidate neural circuits tied to two relevant cognitive constructs: mPFC-vSTR 
for reward-evaluation and dlPFC-dSTR for goal-directed behavior (Kring and Barch 2014, Rizvi, Pizzagalli et al. 2016, 
Höflich, Michenthaler et al. 2019). Pathology of both circuits is correlated with anhedonia (Walsh, Eisenlohr-Moul et 
al. 2019), and causal investigation may differentiate the relative importance of each circuit. 
   
2.2 BACKGROUND  
  
In the past few decades, non-invasive brain stimulation emerged as a promising intervention for treatment-resistant 
depression that is safe with minimal side-effect (Perera, George et al. 2016). The most widely available stimulation 
protocols to treat depression use transcranial magnetic stimulation (TMS) to increase neural activity in the left dlPFC 
(Perera, George et al. 2016) or mPFC (Downar, Geraci et al. 2014, Siddiqi, Taylor et al. 2020), and recent work from 
our lab found promising treatment effects using transcranial alternating current stimulation (tACS) to dlPFC 
(Alexander, Alagapan et al. 2019, Riddle, Rubinow et al. 2020). With multiple spatial targets emerging for the 
treatment of depression, researchers are beginning to understand that heterogeneity in depression symptoms alters 
which spatial targets are most effective at treating depression (Siddiqi, Taylor et al. 2020). Inaccurate spatial 
targeting can render treatment ineffective (Fox, Buckner et al. 2012). Therefore, improved understanding of the 
neural circuits that underly specific symptoms of depression is of critical need. One such symptom, anhedonia, is 
more responsive to stimulation targeting dlPFC than stimulation targeting mPFC (Downar, Geraci et al. 2014, 

Causal role of delta-beta coupling in anhedonia 
 
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Drysdale, Grosenick et al. 2017, Duprat, Wu et al. 2018, Pettorruso, Spagnolo et al. 2018, Siddiqi, Taylor et al. 2020). 
Stimulation to left dlPFC in depressed patients with anhedonia only alleviated depression when symptoms of 
anhedonia decreased (Levkovitz, Sheer et al. 2011). In contrast, stimulation to mPFC only alleviated depression in 
patients without symptoms of anhedonia (Downar, Geraci et al. 2014). Despite recent evidence that dlPFC-dSTR is 
the optimal target for treating anhedonia in depression, the overall response rate is still lower than depressed 
patients without anhedonia (Krepel, Rush et al. 2020). One explanation is that stimulation efficacy is also critically 
dependent on the temporal structure of neural activity (Ali, Sellers et al. 2013). Thus, investigation of the 
electrophysiology of dlPFC-dSTR during goal-directed behavior in patients with anhedonia is critical to further 
advance the efficacy of treatment interventions. 
Neural oscillations are a critical mechanism for interregional communication (Fries 2015), with low frequency 
oscillations facilitating long-distance communication and high frequency enhancing local connectivity (Buzsáki, 
Anastassiou et al. 2012). Cognitive control tasks evoke low frequency neural oscillations in prefrontal cortex that 
couple to high frequency oscillations in posterior cortex (Canolty and Knight 2010, Voytek, Canolty et al. 2010, 
Voytek, Kayser et al. 2015, Helfrich, Huang et al. 2017). This cross-frequency coupling is proposed to be a mechanism 
for prefrontal cortex to exert top-down control (Canolty and Knight 2010). One candidate cross-frequency coupling 
signal for goal-directed behavior is the coupling of delta oscillations (2-4Hz) in prefrontal cortex to beta oscillations 
(15-30Hz) in motor cortex (Wyart, de Gardelle et al. 2012, Riddle, McFerren et al. 2021). In the proposed experiment, 
we investigate the causal role of delta-beta coupling and the dlPFC-dSTR neural circuit in goal-directed behavior. We 
are convinced that our experiment is of high significance since a mechanistic understanding of the neural circuits 
that underlie goal-directed behavior will ultimately allow the rational design of novel brain stimulation techniques 
to more effectively treat depressed patients with anhedonia.  
 
2.3 RISK/BENEFIT ASSESSMENT   
 
2.3.1 KNOWN POTENTIAL RISKS  
 
Risk of Confidentiality Breach: In the unlikely event of a breach of confidentiality, people might discover 
that an individual was involved in this research study. This is especially sensitive because the clinical 
population recruited for this study may be subjected to negative consequences caused by the stigma of 
mental disorders. Furthermore, some might not agree with the principle of participating in research or of 
changing natural brain activity. To avoid breaches in confidentiality, study documents that contain 
personal information and including the informed consent document are kept in locked filing cabinets in 
locked rooms separate from any source documents containing participant dummy identifiers. The 
document that links study ID numbers to personal identifying information is encrypted and protected 
using a password-protected document on a secure server provided by UNC School of Medicine. All data is 
stored in locked cabinets inside locked offices; electronic data will be stored only on password-protected 
computers, and data encryption methods will be used during communication between investigators. Only 
study personnel will have access to the data. All study staff participate in annual human participant 
training that includes education about responsibilities to the minimize risk of confidentiality breach. 
 
Risk of Embarrassment: Self-report assessments contain questions regarding sensitive personal 
information. This risk is necessary in order to assess mood symptoms and associated psychopathology. 
Participants will be assured upon intake that only study personnel will see any clinical ratings and that 
self-identifying information will not be collected alongside HIPAA protected information.  
 

Causal role of delta-beta coupling in anhedonia 
 
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Risk of Injury and Discomfort: The side effects of tACS are mild and transient; in fact, low intensity 
transcranial current stimulation, such as tACS, has been used for over a decade without any report of 
serious side effects (Antal, Alekseichuk et al. 2017). Furthermore, this stimulation mode has nothing to do 
with electroconvulsive therapy that applies many orders of magnitude higher stimulation current. Rather, 
transcranial current stimulation is so weak that it does not cause super-threshold activation of neurons 
(Frohlich and McCormick 2010). However, tACS does have some mild side effects, such as transient mild 
tingling, burning, or itching under the electrode sites. In our previous trial, participants from all three 
groups of stimulation reported either absent or mild side effects, and there was no difference between 
the groups with the exception of ^(o]l]vPo]PZ_~}Z}ZvUAìXìíð
 (Alexander, Alagapan et al. 
2019). To monitor these mild side effects, we will be administering a stimulation questionnaire after each 
stimulation session to determine whether these effects were experienced and at what intensity. Research 
personnel present during these sessions will also check in with the participant periodically during the 
stimulation to see whether they are comfortable. If participant is experiencing severe discomfort (as 
determined by the questionnaire or by self-report), the stimulation will be stopped immediately.  
 
Patients with MDD have an about 20 times higher rate of suicide than average. We have no evidence that 
tACS will in any way increase this likelihood. In a previous clinical trial that administered tACS for five 
consecutive days in a treatment paradigm, 4 participants in the sham/placebo stimulation group 
experienced an increase in suicidal thoughts and only one of those 4 participants reported suicidal intent 
(Alexander, Alagapan et al. 2019). No participants in this previous trial who received tACS reported an 
increase in suicidal ideation from baseline.  Regardless, participants with high suicide risk will not be 
included in this study. If an enrolled participant shows signs of suicide risks that were not apparent during 
enrollment, a referral to UNC Psychiatry will be made. Dr. Schiller, Co-I, will facilitate this process. 
 
We will be using the Suicide Item included in the HAM-D (Snaith, Hamilton et al. 1995)to assess suicide 
risk, as well as the Columbia Suicide Severity Rating Scale (C-SSRS) (Posner, Brown et al. 2011)to determine 
intent for suicide during the enrollment eligibility interview. Inclusion criteria state that the participant 
must be low suicide risk and that potential participant`]Zv}À^o}`]l_]Pv]}v`]oov
eligible for the study. In the event that suicide risk is determined in the first session, the participant will 
be withdrawn from the study and will be provided with a referral to UNC Department of Psychiatry, and 
their mental health care or family medical doctor will be contacted. 
Risk of Psychological Discomfort: There is a psychological element in that some participants may become 
claustrophobic upon entering the small space of the MRI bore. To reduce psychological distress, 
participants are informed that they can withdraw consent and stop participation at any time. Participants 
are monitored throughout the MRI scans and can terminate the scan at any time by squeezing a ball held 
in the hand, and will be quickly removed from the MRI bore. 
Risk of Injury from MRI: Magnetic resonance imaging (MRI) is a non-invasive imaging modality with an 
outstanding safety profile in the United States. The risk of physical injury from the presence of metallic 
objects within the body is almost entirely addressed through the use of screening forms, by requiring 
participants to change into medical gowns, and by using metal detectors at the site of the MRI. Through 
using a core facility at UNC-CH, the Biomedical Research Imaging Center (BRIC), we ensure that risks are 
minimized as BRIC technicians independently screen and prepare participants for imaging. 
 
2.3.2 KNOWN POTENTIAL BENEFITS  
 

Causal role of delta-beta coupling in anhedonia 
 
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This study has not been designed to benefit the individual participants. However, the knowledge gained 
from this study will contribute to understanding about the psychological and biological basis of major 
depressive disorder. Furthermore, the results from this study might be used to develop future 
interventions using non-invasive brain stimulation.  
 
2.3.3 ASSESSMENT OF POTENTIAL RISKS AND BENEFITS  
 
The risks and benefits presented above are no more serious than for other clinical trials in this 
population. Based on the need for complementary and alternative treatments for MDD, the potential 
risks are worth the potential benefits. 
 
2.3.4 REFERRALS FOR MEDICAL FOLLOW-UP 
Epileptic Activity Follow-up: There is a theoretical likelihood that stimulation of neuronal circuits can lead to epileptic 
discharge. To minimize this occurrence, we screen and exclude participants with personal and family history of 
neurological conditions from the study. We further emphasize that there has never been a single report of a seizure 
that resulted from transcranial alternating current stimulation or transcranial direct current stimulation. If 
abnormalities or a seizure is witnessed during the course of the study, a referral will be made to Clio Rubinos at UNC 
Department of Neurology for follow-up. In the theoretical event that a seizure is witnessed that involves the loss of 
consciousness, the participants will be told not to operate a motor vehicle until cleared by the DMV. 
Neurological Abnormality Follow-up: When imaging the brain there is a chance that the MRI scan will reveal a 
neurological irregularity that might be of medical importance to the participant. These incidental findings are 
uncommon and rarely lead to early identification of neurological issues. However, as is standard practice, we allow 
participants the option to choose to be alerted to any incidental findings. In the consent form, participant can opt 
out of being notified about incidental findings. If a researcher notices a neurological abnormality, then they will 
reach out to our collaborators in the department of neurology to investigate the MRI scan further. If the neurologist 
considers the abnormality to be of medical importance, then the participant will be contacted for future steps. It 
should be noted that the research MRI scans used (T1-weighted) are not diagnostic scans and are not sensitive to 
detecting common neurological problems such as brain cancer. There is no expectation that the participant 
population studied in this research program will be of greater likelihood for incidental finding. 
 
3. OBJECTIVE AND OUTCOME MEASURES  
 
 
OBJECTIVES 
OUTCOMES 
JUSTIFICATION FOR OUTCOMES 
Primary 
 
 
To investigate whether delta-
beta tACS will produce an 
increase in goal-directed 
behavior during reward-
based decision-making. 
 
Behavioral metric, percentage 
of hard trials chosen, during 
the Expenditure of Effort for 
Reward Task (EEfRT) at 
Session 1. 
Stimulation is delivered during task 
performance and the amount of 
time on task with stimulation was 
sufficient to observe meaningful 
changes in goal-directed behavior 
across participants in our previous 
study. 
Secondary 
 
 

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OBJECTIVES 
OUTCOMES 
JUSTIFICATION FOR OUTCOMES 
To investigate whether delta-
beta tACS will result in a 
lasting increase in delta-beta 
coupling during eyes-open 
resting-state recorded 
immediately following 
stimulation 
Neural metric, degree of 
phase-amplitude coupling 
between prefrontal delta 
oscillations and left motor 
beta oscillations, quantified 
during eyes-open resting-state 
recorded post-stimulation 
intermittent with task blocks. 
Our previous study delivering 
stimulation in the same manner 
with intermittent resting-state EEG 
found evidence of increased phase-
amplitude coupling from 
stimulation. 
 
Exploratory 
 
 
To investigate the degree to 
which motivation symptoms 
predict individual differences 
in the impact of delta-beta 
tACS on performance. 
Two-dimension factor analysis 
is run on clinical assessments 
to derive a motivation 
symptoms and mood 
symptoms dimension. These 
scores are correlated with the 
impact of tACS on behavior. 
Our previous study found two 
symptom dimensions within 
participants with major depressive 
disorder that captured individual 
differences in reward-based 
decision-making. 
To investigate whether 
rewarding learning might be 
impaired in addition to goal-
directed behavior in 
participants with MDD and 
anhedonia.  
Optimal decision-making for 
rewarding stimulus is 
predicted to be impaired as a 
function of anhedonia and 
may be improved with delta-
beta tACS. 
Previous literature suggests that 
reward-learning is impaired in 
patients with depression and 
symptoms of anhedonia. This 
additional task allows for the 
investigation of the specificity of 
tACS to influence a specific reward-
based cognitive process. 
To investigate whether 
functional connectivity 
between dorsal striatum and 
left lateral prefrontal cortex 
predicts individual 
differences in the impact of 
delta-beta tACS on 
performance. 
Functional connectivity 
analysis of resting-state 
functional magnetic 
resonance imaging is 
correlated with the impact of 
tACS on behavior. 
Previous research has suggested 
that frontal-striatal connectivity is 
related to reward-based decision-
making. Participants with anhedonia 
may show reduced connectivity 
within this neural circuit that is 
predictive of the impact of tACS on 
reward-based decision-making.  
 
4. STUDY DESIGN  
 
4.1 OVERALL DESIGN 
This study is a pilot, three-session, parallel-arm study with transcranial alternating current stimulation (tACS), 
electroencephalography (EEG), and magnetic resonance imaging (MRI) to understand the causal role of delta-beta 
coupling in goal-directed behavior in participants with major depressive disorder (MDD) and symptoms of 
anhedonia. Participants that request to be in the experiment will provide verbal, documented consent to undergo a 
phone screening to assess that the participant meets exclusion/inclusion criteria. Then, participants will complete 
demographic and self-report clinical assessments via REDCap: Patient Health Questionnaire-8 (PHQ-8) with the 
suicide question removed (Kroenke, Spitzer et al. 2001) and the Snaith Hamilton Pleasure Scale (SHAPS) (Snaith, 
Hamilton et al. 1995). Participants that have a PHQ-8 greater than or equal to 8 will be invited to participate in the 

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study. Also, participants will be stratified based on their SHAPS score (50% > 33 on the SHAPS and 50% <= 33). 
Stratification is conducted to ensure a representative spread in anhedonia scores since we are interested in the 
relationship between anhedonia and goal-directed behavior. Thus, some participants will not be invited to 
participate if we have already completed sessions for 24 participants within their median split. The value of 8 for the 
PHQ-8 is used to help ensure that participants will meet criteria for MDD; thus, improving the feasibility of the study. 
The value of 33 for the SHAPS was the median SHAPS score from our previous experiment in participants with MDD, 
and is consistent with findings from other groups. While the PHQ-8 and SHAPS are used to determine eligibility 
(SHAPS is exclusionary only if a stratum is full), additional self-report clinical assessments are administered for 
exploratory analyses.  
The first session will be a virtual clinical assessments session. Participants will provide verbal consent including a 
brief verbal assessment of understanding of study procedures. Next, participants will complete two assessments on 
REDCap while being monitored in a virtual session: the PHQ-9 and must score at least a 10 to proceed with the full 
session, and the SHAPS is used to check if their stratum is full for randomization purposes. After passing this 
additional screening, self-report clinical assessments will be completed on REDCap while being monitored: 
Behavioral Activation System and Behavioral Inhibition System (BIS/BAS) (Carver and White 1994), Temporal 
Experience of Pleasure Scale (TEPS) (Gard, Gard et al. 2006), the State-Trait Anxiety Inventory (STAI) (Spielberger 
2010)Ul[
ion Inventory version 2 (BDI-II) (Beck and Beamesderfer 1974), and Ruminative Responses 
Scale (RRS) (Nolen-Hoeksema, Larson et al. 1999). In addition, participants will undergo clinician-report assessments 
that will be entered onto REDCap: the Mini International Psychiatric Interview for the DSM-V (MINI) (Sheehan, 
Lecrubier et al. 1998), Hamilton Depression Rating Scale (HAM-D) (Hamilton 1960), Columbia-Suicide Severity Rating 
Scale (C-SSRS) (Posner, Brown et al. 2011), and the Maudsley Staging Method (MSM) (Donaldson, Poon et al. 2009). 
Eligibility for the experiment is then determined by a MINI diagnosis of MDD, exclusion based on a present moderate 
to severe substance use disorder or alcohol use disorder, a history of severe substance use disorder or alcohol use 
disorder, or a diagnosis of psychosis or psychotic features. In addition, the participant must have low suicide risk as 
determined by the C-SSRS (see Inclusion/Exclusion criteria above). In the event that a participant has active plans to 
commit suicide, an adverse event is recorded, an acute psychiatric assessment is conducted by our medical monitor, 
Dr. Crystal Schiller, who is a clinical psychologist at UNC-CH, and participation is terminated. In the case that the 
person does not see anyone for their depression, Dr. Schiller will assist the participant in seeking medical care. Dr. 
Rubinow (Principal Investigator, mood disorders expert) will be available as well, in any instances where Dr. Schiller 
is unavailable for acute assessment. 
In the second session, participants provide written consent to participate in the study. Then, participants are 
randomized into one of three arms of the study: delta-beta tACS, control tACS in theta-gamma, or active sham. 
Randomization is stratified by SHAPS level such that there are an equal number of participants that are high 
anhedonia (SHAPS > 33) and low anhedonia (SHAPS <= 33). We expect that of the 48 participants in the final dataset, 
there will be 8 from each of the 6 groups (3 stimulation conditions by 2 anhedonia levels). Two 4.5 by 4.5 centimeters 
stimulation pads are applied to the scalp over the left hemisphere anterior and ventral to F3 and posterior and 
ventral to C3, and a 5 by 7 centimeters stimulation pad is applied centered over FCz in an anterior to posterior 
direction. Prior to any task performance, participants under eyes-closed and eyes-open resting-state while fixating 
on a central point on the monitor. Participants complete titration of the difficult of the EEfRT. Then, participants 
perform 4 blocks of the EEfRT during the collection of EEG. After each block of the EEfRT, there is a 2 minute eyes-
open resting-state scan. Next, participants receive tACS during performance of the EEfRT. Delta-beta tACS, theta-
gamma tACS, or sham-tACS is received during task performance. Stimulation is turned off between blocks, and eyes-
open resting-state EEG is acquired. The total amount of stimulation is approximately 40 minutes for 8 blocks that 

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each last approximately 5 minutes. After tACS, participants complete a stimulation side effects questionnaire and a 
blinding questionnaire. A blinding questionnaire is completed by the experimenter. The blinding questionnaire is a 
single question that asks whether the participant receive stimulation or placebo, and then asks the participant to 
provide an explanation for their response. Based on the results of the stimulation side effects questionnaire, a 
structured adverse events interview is conducted to acquire more information regarding any side effects that were 
o}^À˙Z]PZ_˙Z]]vX
 
For the third session, participants are instructed to arrive at the Biomedical Research Imaging Center (BRIC) in 
Marsico Hall on UNC-CH campus. Participants are instructed to arrive at the facility 30 minutes early to ensure that 
they are ready to go into the MRI for the 60-minute allotted timeslot. During the 60 minutes of scanning, a 5-minute 
structural MR is acquired, 10-minutes of functional MR scans during the eyes-open resting-state are acquired, and 
the remaining time is used to complete as many blocks of the EEfRT as possible. Completion of the MRI session is 
not required for the dataset to be considered a complete dataset. These additional data acquisitions enable 
exploratory analyses that will be used to design future studies. 
 
4.2 SCIENTIFIC RATIONALE FOR STUDY DESIGN 
  
This study is a double-blind, randomized, sham-controlled interventional study. The choice of double-
blind and randomization is important for the integrity of our data, especially for the clinical assessments. 
All individuals involved with data collection (as well as all randomized participants) will be blind to the 
]]v[
 arm assignment until all data has been collected. This will reduce implicit and explicit bias in 
the data collection process.   In this study, participants will be randomized in to one of three arms: active 
sham (i.e., placebo) stimulation, delta-beta tACS, or theta-gamma tACS. This is a follow-up to two of our 
previous studies. One study delivered this same form of stimulation in participants during a cognitive 
control task, which is different from the reward-based decision-making task described here. This study 
used a similar task design in which intermittent resting-state EEG found that delta-beta tACS and theta-
gamma tACS increased the targeted neural activity and modulated behavior associated with the targeted 
neural activity. In this experiment, participants and researchers were successfully blinded to which 
stimulation condition they received. Furthermore, this previous study was a crossover design and, thus, a 
parallel arm design is even more likely to be double-blind because participants only receive one form of 
stimulation. A second study recorded EEG during the EEfRT in patients with MDD. This study found that 
participants with MDD and higher symptoms of anhedonia demonstrated reduced goal-directed behavior 
and reduced delta-beta coupling. This preliminary data provides strong evidence that stimulation 
delivered in a delta-beta pattern should be beneficial to behavioral performance. Furthermore, this study 
serves as a target engagement study and future studies may use these results to develop interventions to 
treat symptoms of anhedonia in MDD. 
 
4.3 JUSTIFICATION FOR DOSE 
 

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Transcranial 
alternating 
current 
stimulation (tACS) is an extremely 
safe 
non-invasive 
stimulation 
paradigm without a single serious 
adverse event directly related to 
stimulation. The same tACS method 
has been used during performance 
of a task with intermittent resting-
state EEG in our previous approved 
UNC 
IRB 
protocol 
18-0003 
(NCT03800030) that was overseen 
by 
Dr. 
Riddle. 
A 
similar 
experimental design using a single 
session 
with 
reward-based 
decision-making tasks and tACS in participants with major depressive disorder (MDD) was approved in our previous 
UNC IRB protocol 16-1911 (NCT03449979) that was overseen by Dr. Riddle. Transcranial Alternating Current 
Stimulation (tACS) applies a weak electric current to the scalp and all previous studies (approximately 15 to date) 
(}u]vZ}o]vv(}Eµ}]uµo]}vZÀ]À^v}v
-]Pv](]v]l]Pv]}v_(}uZ
UNC IRB. Thus, no direct FDA oversight is required and no investigational device application filing is required. Further 
conversations with the regulatory core of the UNC CTSA and the director of the Office of Human Research Ethics 
that administers the UNC IRB over the years have consistently confirmed this classification.  
tACS will be delivered using a cross-frequency stimulation waveform delta-beta (3-20Hz), a control frequency of 
theta-gamma (5-50Hz), or sham in which stimulation is delivered in either delta-beta or theta-gamma for 10 seconds 
and then returns to baseline (Figure 1). These waveforms were designed based on our previous experiment that 
observed these brain activity patterns in a reward-based decision-making task in participants with MDD. The 
stimulation amplitude delivered is standard for tACS studies (Ahn, Mellin et al. 2018, Alexander, Alagapan et al. 2019) 
t stimulation peaks at 1 mA during the peak of the high-frequency component for target electrodes (see Y-axis of 
Figure 2). The high frequency component consists of 3.5 cycles of a sine-wave of the high frequency that is centered 
at 90 degrees of each cycle of the low-frequency component. Stimulation peaks at 2 mA zero-to-peak for the return 
electrode, but the electrode size is 35 cm2 for the return electrode and 20.25 cm2 for each of the target electrodes. 
Thus, the current density is comparable between the two: 0.057 mA/cm2 for the return electrode and 0.049 mA/cm2 
for the target electrodes. 
 
4.4 END OF STUDY DEFINITION 
 
The end of this study is defined as when the last participant completes the study (i.e., the 48th 
participant to complete their final session). 
 
5. STUDY POPULATION 
 
5.1 INCLUSION CRITERIA 
In order to be eligible to participate in this study, a participant must meet all of the following criteria: 
 
Figure 2. Electrical waveforms for delta-beta tACS (left) and theta-gamma 
tACS (right). Peak stimulation amplitude is 1 mA for target electrodes. 

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x 
Between the ages of 18 and 65 
x 
Able to provide informed consent 
x 
Have normal to corrected vision 
x 
Willing to comply with all study procedures and be available for the duration of the study 
x 
Speak and understand English 
x 
Low suicide risk as determined by both the Mini International Neuropsychiatric Interview (MINI) for the 
DSM-5 ~uv}(µ]]]lo}`^Z]PZ_
, by the Columbia Suicide Severity Rating Scale (C-SSRS; 
no for item five regarding intent to act), and by the Hamilton Depression Rating Scale (HAM-D; less than 3 
for the suicidality item). 
x 
Negative pregnancy test for female participants 
x 
PHQ-8 greater than or equal to 8 prior to the first session 
x 
PHQ-9 greater than or equal to 10 at the start of the first session 
x 
A diagnosis of major depressive disorder on the MINI 
 
5.2 EXCLUSION CRITERIA 
A potential participant who meets any of the following criteria will be excluded from participation in the study: 
x 
ADHD (currently under treatment) 
x 
Neurological disorders and conditions, including, but not limited to: 
o 
History of epilepsy 
o 
Seizures (except childhood febrile seizures) 
o 
Dementia 
o 
History of stroke 
o 
Wl]v}v[]
 
o 
Multiple sclerosis 
o 
Cerebral aneurysm 
o 
Brain tumors 
x 
Medical or neurological illness or treatment for a medical disorder that could interfere with study 
participation (e.g., unstable cardiac disease, HIV/AIDS, malignancy, liver or renal impairment) 
x 
Prior brain surgery 
x 
Any brain devices/implants, including cochlear implants and aneurysm clips 
x 
History of current traumatic brain injury  
x 
(For females) Pregnant or breast feeding 
x 
Anything that, in the opinion of the investigator, would place the participant at increased risk or preclude 
Z]]v[(µoo}uo]v`]Z}}uo]}v
 of the study 
x 
DSM-V diagnosis of present moderate or severe substance use disorder or alcohol use disorder, and past 
severe substance use disorder or alcohol use disorder, or psychotic disorder within the last 12 months 
x 
Not taking medications for ADHD or benzodiazepines as these medications often produce specific EEG 
activity that may disrupt our interpretation of the findings 
x 
If major depressive disorder is experienced in episode, the participant must currently be within a depressive 
episode. 
x 
Contraindications for MRI: ferrous metal inside the body, jewelry must be removable, pacemaker or 
cochlear implant. 

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5.3 LIFESTYLE CONSIDERATIONS 
  
None. 
 
5.4 SCREEN FAILURES 
 
In the design of this study, initial phone screening procedures should identify the majority of participants 
who could potentially become screen failures if consented to participate in the clinical trial. However, the 
phone screening process does not necessarily account for all exclusion criteria. After the phone screening, 
each participant is provided with a link to complete two online assessments via REDCap: the Patient Health 
Questionnaire (PHQ-8, without the suicide question) and the Snaith-Hamilton Pleasure Scale (SHAPS). 
Participants must have a PHQ-8 greater than or equal to 8, because this will help to ensure that 
participants will be diagnosed with MDD during session 1. Also, the stimulation is stratified based on 
SHAPS (>33 or <=33). Thus, if 24 participants have completed either of the stratum, then participants 
within that stratum will not be eligible. In the case that a participant meets these criteria, there is still a 
chance that the first interview reveals that they do not meet study criteria. The study personnel 
completing the interviewing process will clearly explain why the participant does not meet criteria. 
However, in the case that a participant does not qualify based on suicide risk, procedures will be followed 
to ensure participant safety. 
 
At the first session and after obtaining participant informed consent, the HAM-D will be administered, 
which contains a question related to suicidal thoughts/actions. If someone answers greater than 2 on the 
HAM-D (i.e., either "suicidal ideas or gesture" or "attempts at suicide") and indicates intent based on the 
C-SSRS, their participation in the study will be immediately stopped and Dr. Schiller (Co-I, responsible for 
participant safety) will be contacted for acute assessment. In the case that the person does not see anyone 
for their depression, Dr. Schiller will assist the participant in seeking medical care. Dr. Rubinow (Co-
Investigator, mood disorders expert) will be available as well, in any instances where Dr. Schiller is 
unavailable for acute assessment.  
 
Assessment may include facilitating contact of the participant with their psychiatrist/primary care 
physician to establish a plan for safety, continued care, and follow-up. If the participant does not have an 
established provider, Dr. Schiller will assist the participant in establishing care. If at any point in the 
assessment, the participant is deemed to be an imminent risk of harm to self or others, study personnel 
will Department for further care. In any instances where Dr. Schiller is unavailable, Dr. Rubinow will be 
available to assist the participant. Dr. Rubinow will be the final arbitrator in case anything (e.g., eligibility, 
safety) is unclear during this process. Dr. Schiller and the researcher will defer to Dr. Rubinow in those 
instances. 
 
5.5 STRATEGIES FOR RECRUITMENT AND RETENTION 
This clinical trial will utilize multiple recruitment strategies to communicate this opportunity to as many 
potential participants as possible.  Our first means is through a referral process.  Participants can be 
referred to the study through their primary mental health care provider or family doctor during routine 
visitsXdZ]˙}(µ]uv`]oolo]v}}[}((]Z}µPZ}µZo,
and Raleigh areas. We estimate that approximately 75 participants will be enrolled from the Chapel 

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Hill/Carrboro area and 25 between Durham and Raleigh. Clinicians will be informed of inclusion criteria 
through email and listserv announcements and be asked to mention this clinical trial to appropriate 
patients and offer them a flyer/ brochure with contact information. Interested individuals can than call or 
email the secure line/address to set up a phone prescreening. We will also be using the UNC i2b2 to send 
request forms to the Carolina Data Warehouse to recruit participants who have been seen at UNC 
Hospitals that meet the inclusion criteria.  
In addition to referrals through primary care providers, we will advertise the study directly to the public 
on websites such as ClinicalTrials.gov, studypages.com, frohlichlab.org and Carolinaneurostimulation.org. 
We will have contact information and a summary of the clinical trial posted on the Frohlich Lab Facebook 
and Twitter pages. We may also be launching a Facebook ad to identify potential patients. This ad will also 
use a pre-screening survey via REDCap to help identify participants. We will also be using the UNC Mass 
email listserv to send out an email that has the studypages.com link. All patient identifiers will be stored 
in REDCap until recruitment is over. When recruitment is over, all patients who do not consent or are not 
eligible for participation in the study will have their responses permanently deleted in REDCap. 
Retention is primarily achieved by condensing the bulk of the experiment into a single stimulation session. 
The payment is $30 for completion of virtual clinical assessments session. Then, completion of the 
stimulation during task provides an addition $50. Finally, participants are invited back for a third session 
that is an MRI session which provides $40. Thus, completion of all study requirements gives $120. 
However, completion of the in-person stimulation session is sufficient to address all primary and 
secondary outcomes. The participant will receive payment at the end of each session on a payment card 
that can be loaded. The research staff will also give each participant a reminder call or email for upcoming 
sessions. Each research staff member will be available for the participants to contact via email or phone. 
 
6. STUDY INTERVENTION 
 
6.1 STUDY INTERVENTION(S) ADMINISTRATION 
 
6.1.1 STUDY INTERVENTION DESCRIPTION 
Participants will be stimulated with the commercial, CE-certified Neuroconn Plus stimulator. The use of 
this device in this study has previously received a NSR designation on initial review by the full UNC IRB. 
The NeuroConn device description is as follows: 
The DC-STIMULATOR is a CE-certified medical device for conducting non-invasive transcranial direct-
current stimulation (tDCS) in humans. DC stimulation is used in clinical practice and in the research of 
stroke, epilepsy, migraine, tinnitus, depression, multiple sclerosis, dementia and chronic headache. The 
DC-STIMULATOR is a micro-processor-controlled constant current source. It meets the highest safety 
standards thanks to (hardware- and software-based) multistage monitoring of the current path. By 
continuously monitoring electrode impedance it can detect insufficient contact with the skin and 
automatically terminate stimulation, maximizing patient safety. 
The device's alphanumeric display and the 4 touch keys allow various stimulation modes to be selected 
and stimulation parameters such as current strength, duration, fade-in and fade-out to be set. 

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DC-STIMULATOR features: 
{ 
1 channel (anodal and cathodal stimulation possible) 
{ 
Adjustable current up to 5,000 µA * 
{ 
Adjustable application time up to 30 minutes * 
{ 
2 standard modes - single (continuous stimulation) and - pulse (cyclical stimulation 
activation/deactivation) with fade in and fade out 
{ 
Customer-specific programs possible (optional) 
{ 
"Study mode" for blind processing of genuine and 'pseudo' stimulation (optional) 
{ 
External trigger input (optional) 
6.1.2 DOSING AND ADMINISTRATION 
 
The research team will first measure each participant's head using the 10-20 system to determine the 
electrode locations. Participants will then be fitted with the 3 electrodes for stimulation: two 4.5x4.5cm 
electrodes placed anterior and ventral to F3 and posterior and ventral to C3, and one 5x7cm electrode 
placed over FCz. Electrodes will be carbon rubber, with Ten20 conductive paste applied. During 
stimulation, the participant will be performing the EEfRT. The stimulator will be triggered by remote 
control from the experiment script and will administer stimulation for five-minutes during each of the 8 
task blocks for a total of 40 minutes of stimulation. After each block of stimulation, an eyes-open resting 
state EEG will be performed. All stimulation involves 20 seconds of ramp-in time and 20 seconds of ramp-
out time. 
 
The stimulation waveforms used in this study for active sham stimulation (placebo) and for delta-beta and 
theta-gamma tACS are delivered at 1 mA zero-to-peak amplitude at the target electrodes and 2 mA zero 
to-peak amplitude at the return electrode. For active sham stimulation, the stimulation is left on for only 
40 seconds before the stimulation ramps back out. This is intended to mimic the skin sensations (e.g., 
itching, burning, tingling) that are experienced at the onset of stimulation, assisting with blinding the 
participant's assignment. 
 
Codes will be randomized to one of the three experimental arms. Researchers will enter the participant 
specific code into the MATLAB script that control the stimulator. Researchers will monitor participants 
during stimulation. Personnel will be thoroughly trained and have trainings documented on the 
transcranial stimulation device and will be present during all stimulation sessions. To monitor side effects 
of stimulation a stimulation effects questionnaire will be administered after each stimulation session. 
 
6.3 MEASURES TO MINIMIZE BIAS: RANDOMIZATION AND BLINDING 
 
Randomization 
Mengsen Zhang, a Frohlich Lab member, will oversee the randomization of 48 6-digit codes, which will be 
used by the experimenters. These codes are directly linked to which treatment participants receive 

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(sham/placebo or 10 Hz tACS at 1 mA) and will be entered into the MATLAB script. 24 codes are generated 
for each of the anhedonia stratum. In addition, 12 codes will be generated (6 extra codes for each stratum) 
in the event that a participant is randomized but discontinues the study. Thus, data will be collected until 
we reach out target of 48 participants, but there will be no bias towards completion for the different arms 
(in the unlikely event that one of the arms has more dropout than the others). 
 
The assignment of each participant cannot be determined by looking at the codes (e.g., codes are not 
sequential, code assignment i v}  }v ^}_ } ^Àv_ vµuX
 Thus, the study is both 
randomized and concealed by virtue of using random numbers generated by a computer. Mengsen Zhang 
has no other responsibility in the study other than providing these randomized codes. If Mengsen Zhang 
leaves the Frohlich Lab, another equivalent researcher who does not work with human participants will 
perform this task. 
 
Blinding 
This study is designed to be double-blind. This means that the participant and the researchers are unaware 
of each participant's assignment until the completion of all data collection. This is accomplished using the 
randomization codes described above. Furthermore, this study utilizes an active sham stimulation. This 
means that the active sham condition includes some stimulation, mimicking the skin sensations associated 
with tACS. In our previously concluded trial, participants in the delta-beta tACS, theta-gamma tACS, and 
active sham groups responded similarly to the blinding questionnaire, indicating that our active sham 
stimulation successfully blinded the participants. 
 
6.4 STUDY INTERVENTION COMPLIANCE 
 
Full compliance with the intervention is defined as completing the entire first session, the MRI session, 
and providing at-home saliva samples. As the intervention is applied and monitored by research 
personnel, compliance can be directly observed. 
 
6.5 CONCOMITANT THERAPY 
  
Eligible participants will be permitted to be receiving concomitant therapy, such as therapy, 
antidepressants, or other medications. Given that the current trial investigates target engagement acutely 
from stimulation, there is no investigation in changes of symptoms. Thus, exploratory analyses will 
consider individual differences that can be explained by differences in concomitant interventions.  The 
only medications not permitted during this trial are anticonvulsants and recent benzodiazepines. The use 
of antidepressants or other therapies is unlikely to affect our outcome, as our primary and secondary 
outcomes are with respect to a single session. 
 
Concomitant therapies will be logged at the first session. Participants will be requested to include the 
dosing for these therapies (i.e., how often per day, how much in each pill, how many pills) as well as when 
they were first prescribed the medication. 
 
6.5.1 RESCUE MEDICINE 
 
N/A 
  

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7. STUDY INTERVENTION DISCONTINUATION AND PARTICIPANT 
DISCONTINUATION/WITHDRAWAL 
  
7.1 DISCONTINUATION OF STUDY INTERVENTION 
 
Discontinuation of stimulation during session 1 means that study participation is halted and no other 
sessions are completed. If a clinically significant finding is identified after enrollment, the investigator or 
qualified designee will determine if any change in participant management is needed. Any new clinically 
relevant finding will be reported as an adverse event (AE). 
 
The study intervention (i.e., 40 minutes of stimulation spaced by intermittent resting-states) will be 
discontinued for the following reasons: 
x 
Any clinical adverse event (AE), laboratory abnormality, intercurrent illness or other medical 
condition, or situation occurs such that continued participation in the study would not be in the 
best interest of the participant. 
x 
The participant meets any exclusion criteria (either newly developed or not previously 
recognized). 
 
7.2 PARTICIPANT DISCONTINUATION/WITHDRAWAL FROM THE STUDY 
 
Participants are free to withdraw from participation in the study at any time upon request. 
 
An investigator may discontinue or withdraw a participant from the study for the following reasons: 
 
x 
Any clinical adverse event (AE), laboratory abnormality, intercurrent illness or other medical 
condition, or situation occurs such that continued participation in the study would not be in the 
best interest of the participant. 
x 
The participant meets any exclusion criteria (either newly developed or not previously 
recognized). 
 
The reason for participant discontinuation or withdrawal from the study will be recorded with the 
participant files. Participants who sign the informed consent form and are not randomized will be 
replaced. Participants who sign the informed consent form, are randomized, and receive the full or part 
of the study intervention (40-minutes of stimulation on session 2), and subsequently withdraw from the 
study, are withdrawn from the study, or discontinue the study will not be replaced. However, participants 
who sign the informed consent form, and are not randomized will be replaced.  
 
7.3 LOST TO FOLLOW-UP 
 
A participant will be considered lost to follow-up if he or she fails to return for 1 scheduled visit and is 
unable to be contacted by the study site staff. All efforts will be made to ensure participants are not lost 
to follow-up, including developing rapport and ensuring enrolled participants are reminded of their 
session dates. To ensure that participants attend the follow-up MRI session, research personnel will be 
flexible in timing, including offering this session later in the day as well as some weekends. Furthermore, 
the at-home saliva sample can be returned at any time. 

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Every effort will be made to contact participants who are lost to follow-up, including contacting via email 
and phone. However, if a participant is lost to follow-up, the missed session will be labeled as missing data 
and our pre-determined analysis plan takes into consideration missing data. Of note, neither the primary 
nor secondary outcomes are dependent on the MRI session or at-home saliva samples. 
 
8. STUDY ASSESSMENTS AND PROCEDURES 
 
8.1 EFFICACY ASSESSMENTS  
Inclusion and exclusion criteria will be determined at the initial session, including concomitant therapies, 
medical history, and diagnosis, to ensure that participants are diagnosed with MDD, with low suicide risk, 
and free of benzodiazepines and anticonvulsant medications. 
 
8.1.1 ELECTROPHYSIOLOGY 
  
1. Resting-state EEG (RSEEG) recordings will be completed several times during the second session. 
Eyes-open and eyes-closed RSEEG will be collected before any task are performed or stimulation 
is delivered. Then, after every task block without and with stimulation, two-minutes of eyes-open 
RSEEG are collected. This measure is used to determine the immediate after-effects of tACS on 
brain activity, specifically on phase-amplitude coupling between delta oscillations in prefrontal 
electrodes and beta oscillations in left motor electrodes and between theta oscillations in 
prefrontal electrodes and gamma oscillations in bilateral parietal-occipital electrodes. 
2. Phase-amplitude coupling between delta-beta and theta-gamma oscillations will be acquired 
during task performance of the EEfRT as measured in our previous study (Riddle, Alexander et al., 
in review) and similar to our previous study with delta-beta tACS and theta-gamma tACS (Riddle, 
McFerren et al. 2021). 
 
8.1.2 TASK PERFORMANCE 
1. Goal-directed behavior: In the Expenditure of Effort for Reward Task (EEfRT), goal-directed 
behavior is quantified as the percentage of trials in which the participant chose the HARD task 
instead of the EASY task. In our previous experiment, goal-directed behavior negatively and 
significantly correlated with anhedonia symptom severity. Goal-directed behavior ranges from 0 
to 100% and task difficulty is titrated to push goal-directed behavior down to <85%. In our 
previous use of this task, minimum goal-directed behavior was 23%. Thus, we expect performance 
to range from approximately 23-85%. 
2. Reward-evaluation: In the EEfRT, reward-evaluation is quantified as the slope of the linear fit of 
percentage HARD trials for each incentive level ($2.50 to $6 in $0.50 increments), dependent 
variable, to the incentive level, independent variable. In our previous experiment, reward-
evaluation positively and significantly correlated with trait anxiety severity in participants with 
depression. In our previous experiment, the average reward evaluation was 15% per $1. 
8.1.3 CLINICAL EVALUATIONS 
  

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1. MINI INTERNATIONAL PSYCHIATRIC INTERVIEW FOR THE DSM-V (MINI) is a structured interview that is an 
abbreviation of the Structured Clinical Interview for the DSM (Sheehan, Lecrubier et al. 1998). The 
MINI is ideal for the diagnosis of MDD and to be used as screening technique for exclusion 
diagnoses. These data are used to determine eligibility after the first session. 
2. HAMILTON DEPRESSION RATING SCALE (HAM-D) is a 17-item assessment that determines depression 
severity (Hamilton 1960). This assessment is used to complement the BDI-II. Items within the 
HAM-D have been shown to capture different dimensions of MDD, such as anhedonic and 
anxiosomatic symptoms. This scale is also used to determine suicide risk. Items are summed to a 
total score ranging 0 to 54. 
3. COLUMBIA-SUICIDE SEVERITY RATING SCALE (C-SSRS) is used to screen for suicide risk (Posner, Brown et 
al. 2011). In the event that a participant reports plans or intention to commit suicide, then an 
acute psychiatric assessment is conducted by Dr. Crystal Schiller. 
4. MAUDSLEY STAGING METHOD (MSM) is a method for measuring treatment resistance in participants 
with depression on a scale of 3 to 15 (mild = 3-6; moderate = 7-10; severe=11-15)(Donaldson, 
Poon et al. 2009). 
 
8.1.4 SELF-REPORT ASSESSMENTS 
 
1. The Beck Depression Inventory (BDI) (Spielberger et al. 1983) will be administered at session 1. 
The BDI is a 21-item, self-report rating inventory that measures characteristic attitudes and 
symptoms of depression. Scores range from 0 to 63. 
2. The Behavioral Inhibition and Behavioral Activation Self Report Scales (BIS/BAS) (Carver and White 
1994) will be completed during the first session. These scales are used to monitor the perceived 
sensitivity to reward and punishment. BIS/BAS is broken into four sub-scores: BIS (7 to 28), BAS 
drive (4-16), BAS fun-seeking (4-16), and BAS reward (7-20). 
3. The State-Trait Anxiety Inventory (STAI) (Spielberger et al. 1983) will be completed during the first 
session. These 40 items are used to quantify frequencies of feelings of anxiety. STAI has two 
subscores, state and trait anxiety, range 20 to 80. 
4. The Snaith-Hamilton Pleasure Scale (SHAPS) (Snaith, Hamilton et al. 1995) will be completed 
online before the first session to stratify randomization and again at the first session. This scale is 
used to assess anhedonia, range 14 to 56. 
5. Patient Health Questionnaire-9 (PHQ-9) is a 9-item assessment that mirrors the criteria for major 
depressive disorder (Kroenke, Spitzer et al. 2001). This assessment is used as a screening tool that 
is completed prior to the first in-person session to increase the feasibility of the study by only 
running sessions with participants that will most likely be diagnosed with MDD, an inclusion 
criterion. Range 0 to 27. 
6. Temporal Experience of Pleasure Scale (TEPS) is an 18-item assessment that quantifies symptoms 
of anhedonia along two sub-dimensions: consummatory (8 to 48) and anticipatory (10 to 60) 
(Gard, Gard et al. 2006). This assessment may provide additional insight into subtypes of 
anhedonia symptoms and is acquired during the first session.  
7. Ruminative Responses Scale (RRS) is a 22-item assessment that quantifies the degree to which 
participants engage in depressive rumination, range 31 to 155 (Nolen-Hoeksema, Larson et al. 
1999). This assessment is completed at the first session. 
 
 
8.2 SAFETY AND OTHER ASSESSMENTS 

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1. 
The Columbia Suicide Severity Rating Scale (C-SSRS) (Posner, Brown et al. 2011) will be administered 
by trained research personnel at the first session to thoroughly assess suicide risk. If a participant 
reports experiencing either suicidal ideation or suicidal behavior, research personnel will collect 
more information from the participant to deliver to either Dr. Schiller or Dr. Rubinow. Clinical 
personnel will decide if an acute assessment is required. Acute assessment may include facilitating 
contact of the participant with their psychiatrist or primary care physician to establish a plan for 
safety, continued care, and follow-up. If the participant does not have an established provider, Dr. 
Schiller or Dr. Rubinow will assist in establishing a care plan. If at any point during the assessment, 
the participant is deemed an imminent risk of harm to self or others, study personnel will enlist the 
aid of campus security to ensure that the participant is safely escorted to the Emergency 
Department for further care. Dr. Schiller and/or Dr. Rubinow will decide if participation should be 
stopped after the acute assessment. If an acute assessment is required, then participation will be 
halted. 
2. 
A structured interview probing for the experience of adverse events based on the responses from 
the stimulation side effects questionnaire will be completed after stimulation on the second session. 
Dr. Frohlich, Dr. Schiller, or Dr. Rubinow will use the completed interview to assess the severity of 
the adverse event and its relationship to the study intervention.  
3. 
A stimulation side effects questionnaire will be administered at the end of each stimulation session. 
This tool will be used as a safety measure and to collect data on Z]]v[
experience. A 
similar questionnaire was used in a previous study (IRB# 13-2995) to determine ability to 
successfully blind the participants using sham transcranial current stimulation.  
   
8.3 ADVERSE EVENTS AND SERIOUS ADVERSE EVENTS 
 
8.3.1 DEFINITION OF ADVERSE EVENTS (AE) 
 
Adverse event means any untoward medical occurrence associated with the use of an intervention in 
humans, whether considered intervention-related (21 CFR 312.32 (a)).  
 
8.3.2 DEFINITION OF SERIOUS ADVERSE EVENTS (SAE)  
 
An adverse event (AE) or suspected adverse reaction is considered "serious" if, in the view of the 
investigator, it results in any of the following outcomes: death, a life-threatening adverse event, inpatient 
hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or 
substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. 
Important medical events that may not result in death, be life-threatening, or require hospitalization may 
be considered serious when, based upon appropriate medical judgment, they may jeopardize the 
participant and may require medical or surgical intervention to prevent one of the outcomes listed in this 
definition. Examples of such medical events include allergic bronchospasm requiring intensive treatment 
in an emergency room or at home, blood dyscrasias or convulsions that do not result in inpatient 
hospitalization, or the development of drug dependency or drug abuse. 
 
8.3.3 CLASSIFICATION OF AN ADVERSE EVENT 
8.3.3.1 SEVERITY OF EVENT 

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 All adverse events (AEs) will be assessed by the principal investigator and/or co-investigator(s) using the 
following guidelines:  
 
{ 
Mild t Àvµ]u]v]uo}v}uvv}v}]v(`]ZZ]
activities.  
{ 
Moderate t Events result in a low level of inconvenience or concern with the therapeutic 
measures. Moderate events may cause some interference with functioning. 
{ 
Severe t Àv ]vµ  ]]v[ µµo ]o˙ ]À]˙ v u˙ µ] ˙
therapy or other treatment. Severe events are usually potentially life-threatening or 
incapacitating.  Of note, the term ^À_}v}v]o˙µ}^]}µ_X
 
 
8.3.3.2 RELATIONSHIP TO STUDY INTERVENTION 
 
All adverse events (AEs) must have their relationship to study intervention assessed by the principal 
investigator and co-investigator(s) who examines and evaluates the participant based on temporal 
relationship and their clinical judgment. The degree of certainty about causality will be graded using the 
categories below. In a clinical trial, the study product must always be suspect.  
 
{ 
Definitely Related t There is clear evidence to suggest a causal relationship, and other possible 
contributing factors can be ruled out. The clinical event, including an abnormal laboratory test 
result, occurs in a plausible time relationship to study intervention administration and cannot be 
explained by concurrent disease or other drugs or chemicals. The response to withdrawal of the 
study intervention (dechallenge) should be clinically plausible. The event must be 
pharmacologically or phenomenologically definitive, with use of a satisfactory rechallenge 
procedure if necessary. 
{ 
Probably Related t There is evidence to suggest a causal relationship, and the influence of other 
factors is unlikely. The clinical event, including an abnormal laboratory test result, occurs within a 
reasonable time after administration of the study intervention, is unlikely to be attributed to 
concurrent disease or other drugs or chemicals, and follows a clinically reasonable response on 
withdrawal (dechallenge). Rechallenge information is not required to fulfill this definition. 
{ 
Potentially Related t There is some evidence to suggest a causal relationship (e.g., the event 
occurred within a reasonable time after administration of the trial medication). However, other 
(} u˙ ZÀ }v]µ } Z Àv ~XPXU Z ]]v[ o]v]
}v}u]vÀvXoZ}µPZvu˙}vo˙^}]o˙o_}}v
can be flagged as requiring more infou]}vvoµP}^}o˙o_
^(]v]o˙o_U}]X
 
{ 
Unlikely to be related t A clinical event, including an abnormal laboratory test result, whose 
temporal relationship to study intervention administration makes a causal relationship 
improbable (e.g., the event did not occur within a reasonable time after administration of the 
study intervention) and in which other drugs or chemicals or underlying disease provides plausible 
˘ov]}v~XPXUZ]]v[o]v]
cal condition, other concomitant treatments). 
{ 
Not Related t The AE is completely independent of study intervention administration, and/or 
evidence exists that the event is definitely related to another etiology. There must be an 
alternative, definitive etiology documented by the clinician. 
 
 

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8.3.3.3 EXPECTEDNESS  
 
The principal investigator (Dr. Frohlich), with input from the co-investigators (Dr. Schiller and Dr. Rubinow) 
when necessary, will determine whether an adverse event (AE) is expected or unexpected in this 
population.  The principal investigator (Dr. Flavio Frohlich) is an expert in non-invasive brain stimulation 
and will provide his expert opinion in regard to this as well. An AE will be considered unexpected if the 
nature, severity, or frequency of the event is not consistent with the risk information previously described 
for the study intervention. 
8.3.4 TIME PERIOD AND FREQUENCY FOR EVENT ASSESSMENT AND FOLLOW-UP 
 
The occurrence of an adverse event (AE) or serious adverse event (SAE) may come to the attention of 
study personnel during study visits, or the study participant may report AE or SAEs outside of a scheduled 
study visit. 
 
All AEs including local and systemic reactions not meeting the criteria for SAEs will be captured on the 
appropriate case report form (CRF). Information to be collected includes event description, time of onset, 
o]v]]v[uv}(À]˙Uo]}vZ]}µ˙}µ~
ssessed only by those with the training 
and authority to make a diagnosis), and time of resolution/stabilization of the event. All AEs occurring 
while on study must be documented appropriately regardless of relationship. All AEs will be followed to 
adequate resolution.   Any medical condition that is present at the time that the participant is screened 
will be considered as baseline and not reported as an AE. However, if the study participant[}v]]}v
deteriorates at any time during the study, it will be recorded as an AE. Changes in the severity of an AE 
will be documented to allow an assessment of the duration of the event at each level of severity to be 
performed. AEs characterized as intermittent require documentation of onset and duration of each 
episode.   
 
Research personnel will record all reportable events with start dates occurring any time after informed 
consent is obtained until 7 (for non-serious AEs) or 30 days (for SAEs) after the last day of study 
participation. At each study visit, research personnel will inquire about the occurrence of AE/SAEs since 
the last visit. Events will be followed for outcome information until resolution or stabilization. All AEs 
including local and systemic reactions not meeting the criteria for SAEs will be captured on the appropriate 
case report form (CRF)X/v(}u]}v}}oo]voµÀv]]}vU]u}(}
assessment of severity, relationship to study product (assessed only by those with the training and 
authority to make a diagnosis), and time of resolution/stabilization of the event. All AEs occurring while 
on study must be documented appropriately regardless of relationship. All AEs will be followed to 
adequate resolution. 
 
Any medical condition that is present at the time that the participant is screened will be considered as 
o]vvv}}vX,}`ÀU](Zµ˙]]v[}v]]}v]
during the study, it will be recorded as an AE.  
 
Changes in the severity of an AE will be documented to allow an assessment of the duration of the event 
at each level of severity to be performed. AEs characterized as intermittent require documentation of 
onset and duration of each episode. 
 

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Research personnel will record all reportable events with start dates occurring any time after informed 
consent is obtained until 7 (for non-serious AEs) or 30 days (for SAEs) after the last day of study 
participation.  At each study visit, the investigator will inquire about the occurrence of AE/SAEs since the 
last visit.  Events will be followed for outcome information until resolution or stabilization. 
 
8.3.5 ADVERSE EVENT REPORTING 
 
We will be adopting the following reporting procedures:  
 
What event is 
reported 
When is event 
reported 
By whom is event 
reported 
To whom is event 
reported 
Fatal or life-
threatening 
unexpected, suspected 
serious adverse 
reactions 
Within 24 hours of 
initial receipt of 
information 
Investigator 
x 
Local/internal 
IRB 
Non-fatal, non-life-
threatening 
unexpected, suspected 
serious adverse 
reactions 
Within 48 hours of 
initial receipt of 
information 
Research Personnel 
x 
Local/internal 
IRB 
Unanticipated adverse 
device effects 
Within 10 working days 
of investigator first 
learning of effect  
Investigator 
x 
Local/internal 
IRB 
Unanticipated Problem 
that is not an SAE 
Within 7 days of the 
investigator becoming 
aware of the problem 
Investigator 
x 
Local/internal 
IRB 
  
8.3.6 REPORTING OF PREGNANCY  
 
There have been some scientific studies using transcranial electrical stimulation in pregnancy (see 
(Kurzeck, Kirsch et al. 2018) and (Konstantinou, Vigod et al. 2020) for review). None of these studies 
reported side-effects specific to pregnancy or fetal development. Furthermore, given the history of an 
extremely safe profile for non-invasive electrical stimulation with zero serious adverse events after 
decades of use, we assume there to be no risk to pregnant women. Nonetheless, pregnant women will be 
excluded from this study because they are a protected group. Female participants will be asked if there is 
a possibility that they are pregnant at both sessions. If the participant says yes or is unsure, then we will 
verify pregnancy status via a urine pregnancy test. Only upon a verbal confirmation that pregnancy is not 
possible or a negative finding from a pregnancy test will we proceed with the experiment. 
 
8.4 UNANTICIPATED PROBLEMS 
 
8.4.1 DEFINITION OF UNANTICIPATED PROBLEMS (UP) 
 

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The Office for Human Research Protections (OHRP) considers unanticipated problems involving risks to 
participants or others to include, in general, any incident, experience, or outcome that meets all of the 
following criteria: 
 
{ 
Unexpected in terms of nature, severity, or frequency given (a) the research procedures that are 
described in the protocol-related documents, such as the Institutional Review Board (IRB)-
approved research protocol and informed consent document; and (b) the characteristics of the 
participant population being studied; 
{ 
Related or pos]o˙o}]]]}v]vZZ~^}]o˙o_u
reasonable possibility that the incident, experience, or outcome may have been caused by the 
procedures involved in the research); and 
{ 
Suggests that the research places participants or others at a greater risk of harm (including 
physical, psychological, economic, or social harm) than was previously known or recognized. 
 
8.4.2 UNANTICIPATED PROBLEM REPORTING  
 
If a UE occurs, the IRB will be notified, and the study will be adjusted as needed to protect the health and 
safety of the participants. Depending on the nature of the UE, the research protocol, inclusion/exclusion 
criteria, and informed consent will be changed to reflect the possibility of this event reoccurring. During 
this time, no new participants will be recruited and the research procedures for currently enrolled 
participants will be stopped. Each UE will be recorded and reported throughout the study.   
 
8.4.3 REPORTING UNANTICIPATED PROBLEMS TO PARTICIPANTS  
 
Any new information gained during the study that may affect a participant[willingness to continue in the 
study will be reported to all currently enrolled participant. 
 
9. STATISTICAL CONSIDERATIONS  
 
Statistical analyses will be performed by Dr. Justin Riddle. 
 
9.1 STATISTICAL HYPOTHESES 
 
x 
Primary Outcome hypothesis: 
o Null: There is no difference in goal-directed behavior between baseline EEfRT and EEfRT 
during stimulation as a function of stimulation type (delta-beta tACS, theta-gamma tACS, 
or active-sham). 
o Alternate: There is a difference in goal-directed behavior between baseline EEfRT and 
EEfRT during stimulation as a function of stimulation type (delta-beta tACS, theta-gamma 
tACS, or active-sham). 
 
x 
Secondary Outcome hypothesis: 
o Null: There is no difference in delta-beta phase-amplitude coupling strength between 
prefrontal electrodes and left motor electrodes for post-stimulation resting-state periods 
as a function of stimulation type (delta-beta tACS, theta-gamma tACS, or active-sham). 

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o Alternate: There is a difference in delta-beta phase-amplitude coupling strength between 
prefrontal electrodes and left motor electrodes for post-stimulation resting-state periods 
as a function of stimulation type (delta-beta tACS, theta-gamma tACS, or active-sham). 
 
x 
Exploratory Outcome hypothesis 1: 
o Null: The impact of delta-beta tACS on goal-directed behavior is not correlated with 
motivation symptom severity. 
o Alternative: The impact of delta-beta tACS on goal-directed behavior is correlated with 
motivation symptom severity. 
 
x 
Exploratory Outcome hypothesis 2: 
o Null: Functional connectivity during the resting-state between dorsal striatum and lateral 
prefrontal cortex is not predictive of the impact of delta-beta tACS on goal-directed 
behavior. 
o Alternative: Functional connectivity during the resting-state between dorsal striatum and 
lateral prefrontal cortex is predictive of the impact of delta-beta tACS on goal-directed 
behavior. 
 
9.2 SAMPLE SIZE DETERMINATION 
 
The sample size is 48 participants in the final dataset to be used in analysis. However, to ensure that 48 
participants complete the experiment, we conservatively estimate to enroll 100 participants as a ceiling 
for the sake of IRB approval. The motivation for the sample size of 48 participants in the analysis is 
explained below. The sample size is determined based on previous experiments from our group: the 
effect size of previous findings and the reliability of our estimates. Our estimators are precise due to 
sufficient number of trials per condition with each participant and that the tasks are titrated to the 
individual. 
Primary outcome: Cross-frequency transcranial alternating current stimulation (tACS) to lateral 
frontal cortex at delta-beta frequency will increase goal-directed behavior relative to placebo stimulation. 
Previous Data: The planning and refinement of the proposed study was informed by our previous 
experiments that serve as preliminary data for the proposal. In our previous experiment, we delivered 
cross-frequency tACS to lateral frontal cortex at delta-beta frequency to modulate performance on a 
cognitive control task relative to placebo stimulation (Riddle, McFerren et al. 2021). As in the current 
proposal, a specific component of the task was identified to drive an increase in delta-beta coupling. This 
was the component that was altered by delta-beta tACS. In the previous experiment, we found a 
significant interaction between stimulation (delta-beta tACS or theta-gamma tACS, minus placebo) and 
our cognitive control dimension of interest with a partial-eta square of 0.288 with N = 23. For the specific 
comparison of interest, we found increased reaction time relative to placebo with an effect size of 0.480 
from pair-wise t-test with N = 23. 
Sample Size Determination and Power Calculation: Our previous effect size based on behavioral 
modulation from delta-beta tACS used a crossover design. The experiment proposed here will use a 
parallel arm design; however, we will calculate the effect of stimulation as a difference from the baseline 

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performance levels that are derived from our titration of task difficulty. Therefore, the primary analysis 
will use a mixed-measures ANOVA with one within-participants factor (before and during stimulation) and 
one between-participants factor (delta-beta, placebo). With an effect size of 0.288 partial-eta square, we 
estimate that we need at least 21 participants to reach 80% statistical power with a correlation of 0.7. 
Using a conservative estimate of 0.5 correlation between estimates, we still reach 93% statistical power 
with 48 participants. 
 
Figure 3. Power calculation for the impact of delta-beta tACS on performance tested with 
ANOVA: between-participants factor of stimulation type and within-participants factors 
before versus after stimulation. Interaction effect was modeled as a within-between 
ANOVA using the G*Power software: 3 groups, 2 measurements, partial-eta square 0.288, 
correlation between estimates conservatively at 0.5. Proposed number of participants, 
48, is depicted in red. 
Data will be collected until we reach 48 participants. Given the similarity in stimulation 
methodology between the current experiment and our previous experiment (Riddle, McFerren et al. 
2021), we anticipate adequate levels of power for hypothesis testing with 48 total participants. 
 
Secondary outcome: Cross-frequency transcranial alternating current stimulation (tACS) to lateral 
frontal cortex at delta-beta frequency will increase delta-beta coupling relative to placebo stimulation. 
Previous Data: The planning and refinement of the proposed study was informed by our previous 
experiment that serves as preliminary data for the proposal. In our previous experiment, we delivered 
cross-frequency tACS to lateral frontal cortex at delta-beta frequency to modulate performance on a 
cognitive control task relative to placebo stimulation (Riddle, McFerren et al. 2021). As in the current 
proposal, resting-state EEG sessions were included between each task block such that phase amplitude 
coupling could be estimated with data that was not corrupted by the stimulation artifact from tACS. In 

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the previous experiment, we found that delta-beta tACS increased delta-beta coupling with an effect size 
of 0.382 and a sample size of 23 participants. 
Sample Size Determination and Power Calculation: Our previous effect size based on the 
modulation of delta-beta coupling from delta-beta tACS used a crossover design. The experiment 
proposed here will use a parallel arm design; however, we will calculate the effect of stimulation as a 
difference from the baseline coupling levels that are derived from resting-state EEG prior to stimulation. 
Therefore, the primary analysis will use a mixed-measures ANOVA with one within-participants factor 
(before and during stimulation) and one between-participants factor (delta-beta or placebo). With an 
effect size of 0.382, we estimate that we need at least 21 participants to reach 80% statistical power. With 
48 participants, then we expect power to exceed 95% with a conservative estimate of 0.5 correlation 
between estimates. 
 
Figure 4. Power calculation for the impact of delta-beta tACS on delta-beta coupling. 
Interaction effect was modeled as a two-way ANOVA with factors: within-participant 
before or after stimulation and between-participant factor of stimulation type (delta-beta 
tACS, theta-gamma tACS, or placebo) using the G*Power software. Number of groups = 
3, number of measurements = 2, effect size = 0.382, correlation between estimates 
conservatively at 0.5. Proposed total number of participants is 48 depicted in red. 
Data will be collected until we reach 48 participants. Given the similarity in stimulation 
methodology between the current experiment and our previous experiment (Riddle, McFerren et al. 
2021), we anticipate adequate levels of power for hypothesis testing with 48 total participants. 
 
 
9.3 POPULATIONS FOR ANALYSES 

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Every effort will be made to ensure all enrolled and randomized participants complete all study sessions 
as described in this protocol. However, a priori, we determined that our population for analysis will be a 
modified intention-to-treat (ITT) analysis dataset. For this study, enrolled eligible participants will be 
randomized to receive 40 minutes of stimulation. If a participant completes the intervention (i.e., 
completes the first session), they will be included in all analyses moving forward. 
 
As 
previously 
stated 
in 
Section 
7 
Study Intervention 
Discontinuation 
and 
Participant 
Discontinuation/Withdrawal, enrolled participants who do not complete session 1 will be replaced. 
Therefore, with this population for analysis plan, we anticipate having data from 48 participants that are 
eligible for analysis. 
 
9.4 STATISTICAL ANALYSES 
 
9.4.1 GENERAL APPROACH 
 
All testing described below assumes a significance threshold of p = 0.05. Analyses will be deemed to be 
statistically significant if the p-value is less than this threshold. An analysis that does not exceed this 
threshold will be considered inconclusive. Continuous data will be described using means, standard 
deviations, and confidence intervals, while categorical data will be described using counts/percentages.  
 
There may be additional covariates included in the analysis. Data will be assessed for normality and, if 
deemed necessary, corrective procedures will be applied (e.g., log normalization). Based on our previous 
dataset, we expect that the variables used here will be approximately Gaussian. However, if the 
distribution of a variable displays a skewed tail and a test for normality fails, then it is justified to use a 
corrective procedure. This correction will be applied upon consideration of the variables themselves, and 
not based on the result of the intended analysis. 
 
Data will be collected until 48 participants complete the first session and all data is usable. Given that 
there is only a single session, we expect to have complete data and all analyses will include the full 
participant pool. However, if there are technical errors that are not caught in time, then the affected 
analyses may have less participants. In this scenario, the data for a participant is then completely removed 
from the analysis. We emphasize that lost data is typically of greater concern for longitudinal and multi-
session studies. If a subset of participants does not complete the second session in this experiment, then 
only the analysis of exploratory outcome 2 will be affected. 
 
9.4.2 ANALYSIS OF THE PRIMARY OUTCOME (BEHAVIOR) 
 
Goal-directed behavior will be calculated as the average decision to perform the HARD task. The average 
for the four blocks prior to stimulation and the four blocks during stimulation will be calculated. A two-
way analysis of covariance (ANCOVA) will be performed using within-participant factor of time (before or 
during stimulation), between-participant factor stimulation type (delta-beta tACS, theta-gamma tACS, or 
active-sham), and anhedonia symptom severity as a linear covariate (SHAPS at session 1 as a continuous 
variable). We hypothesize to find an interaction between time and stimulation type in the ANCOVA. Post-
Z} ]((v `]oo  ]vÀ]P µ]vP dµl˙[ uZ} }  uµo]o }
hypothesize that the predicted interaction will be driven by an increase in goal-directed behavior for delta-

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beta tACS. Sensitivity analyses will be conducted to evaluate the specificity of these effects: a similar 
analysis with reward-evaluation as the dependent variable and we do not expect that delta-beta tACS will 
have any effect on reward-evaluation. 
 
Furthermore, we hypothesize that the inclusion of the SHAPS covariate is critical to our findings in that 
participants with the greatest symptoms of anhedonia will demonstrate the greatest increase to goal-
directed behavior. This effect will be investigated by a correlation between the baseline symptoms of 
anhedonia (SHAPS) and the change in goal-directed behavior for participants that received delta-beta 
tACS. The specificity of this effect will be investigated as a difference in correlation between the 
relationship of anhedonia symptoms and goal-directed behavior for the group that received sham tACS.  
 
9.4.3 ANALYSIS OF THE SECONDARY OUTCOME (ELECTROPHYSIOLOGY) 
 
Delta-beta phase amplitude coupling will be calculated between the phase of delta oscillations (2-3 Hz) in 
prefrontal electrodes (FCz and surrounding electrodes) and the amplitude of beta oscillations (15- 25 Hz) 
in left motor electrodes (C3 and surrounding electrodes). The instantaneous phase and amplitude of these 
oscillations will be calculated by averaging the signal in these two regions of interest, band-filtering the 
signal to the specified range, and then performing the Hilbert transform on the signal. Phase-amplitude 
coupling (PAC) is then calculated by creating a hybrid signal using the amplitude of beta oscillations in left 
motor electrodes and the phase of delta oscillations in prefrontal electrodes:  
 
2#%L Z
ˆ
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points 
The PAC value is normalized by creating a null distribution by randomly shifting the beta timeseries by at 
least 10% of the number of time points. Then, PAC is calculated between the delta-phase timeseries and 
each of these randomly shifted beta-amplitude timeseries. Finally, PACZ is calculated as the z-transformed 
true PAC value relative to the null distribution. 
 
The average for the eight resting-state period after each task block prior to stimulation and the eight 
resting-state periods after each task block during stimulation will be calculated. A two-way analysis of 
covariance (ANCOVA) will be performed using within-participant factor of time (before or during 
stimulation), between-participant factor stimulation type (delta-beta tACS, theta-gamma tACS, or active-
sham), and anhedonia symptom severity as a linear covariate (SHAPS at session 1 as a continuous 
variable). We hypothesize to find an interaction between time and stimulation type. Post-hoc differences 
`]oo]vÀ]Pµ]vPdµl˙[uZ}}uµo]o}u]}vXtZ˙}
predicted interaction will be driven by an increase in delta-beta coupling for delta-beta tACS. Sensitivity 
analyses will be conducted to evaluate the specificity of these effects: a similar analysis with theta-gamma 
coupling as the dependent variable and we do not expect that delta-beta tACS will have any effect on 
theta-gamma coupling. In addition, we will perform an analysis on the topographic specificity of the 
increase in delta-beta coupling across the scalp. We hypothesize that the increase in delta-beta coupling 
will be specific to the left motor electrodes. 
 
9.4.4 ANALYSIS OF THE EXPLORATORY OUTCOMES 
First exploratory outcome: symptom dimensions 

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A two-dimension factor analysis will be run on all sub-scores from clinical assessments to derive a mood 
and motivation composite symptom score. This analysis was used in our previous study and found that goal-
directed behavior negatively correlated with motivation symptoms. Thus, we hypothesize that the severity of 
motivation symptoms will correlate with the degree to which delta-beta tACS will increase goal-directed behavior. 
The analysis will be run as a Pearson correlation within the group that received delta-beta tACS. To control for the 
specificity of this effect, this correlation will be compared to sham tACS, mood symptoms, and reward-evaluation. 
Second exploratory outcome: functional connectivity in frontal-striatal circuity 
 
Using the resting-state functional magnetic resonance imaging data, we will calculate the strength of 
functional connectivity between the dorsal striatum and the lateral prefrontal cortex. We hypothesize that 
participants with major depressive disorder and anhedonia will show decreased strength in connectivity, and that 
individual differences in this functional connectivity strength will be predictive of the change in goal-directed 
behavior with delta-beta tACS. The analysis will be run as a Pearson correlation within the group that received 
delta-beta tACS. To control for the specificity of this effect, this correlation will be compared to sham tACS and 
reward-evaluation. 
9.4.5 SAFETY ANALYSES 
 
The stimulation questionnaire will be administered for the first session after stimulation. This 
questionnaire solicits ratings of 14 possible adverse effects associated with electrical stimulation, on a 
scale of 1 (low) to 4 (very high). Paired t-tests with random effect "participant" will be calculated per 
adverse effect to determine if there are any differences in adverse effect severity between groups (delta-
beta tACS versus active-sham, theta-gamma tACS versus active-sham). Severity per adverse effect will be 
described with mean and standard deviation. 
 
The Adverse Events Structured Interview will be administered by research personnel following the 
stimulation session. This interview solicits open-ended descriptions of each of the symptoms that were 
 }  ^À˙ Z]PZ_ ˙ Z ]]vX
 A linear model with random effect "participant" will be 
calculated per adverse effect to determine if there are any differences in adverse effect severity between 
groups (delta-beta tACS, theta-gamma tACS, active-sham tACS as categorical independent variables) and 
adverse effect severity as the continuous dependent variable. Severity per adverse effect will be described 
with mean and standard deviation. 
 
9.4.6 BASELINE DESCRIPTIVE STATISTICS 
 
All baseline descriptive statistics will be analyzed either using paired t-tests with random effect 
"participant" or chi-square tests where deemed appropriate. Descriptive statistics will be described based 
on the General Approach described in 9.4.1. 
 
9.4.7 PLANNED INTERIM ANALYSES  
 
If there is an unexpected event that is related to tACS, then a blinded interim descriptive analyses on the 
safety measures (blinded adverse effects and responses to the stimulation questionnaire) will be 
performed. If there is a reason to review unblinded information, a researcher not involved in the data 
collection for the study, Mengsen Zhang or another researcher in the group, will be access the list of 

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participant identification numbers kept by Mengsen Zhang. Participant identification numbers will be in a 
table according to the two arms of the study; however, the treatment of each arm will not be disclosed. 
This information will allow the researcher to compare the two groups.  
 
There are no other planned interim analyses. 
 
9.4.8 SUB-GROUP ANALYSES 
 
Sub-group analyses will not be used in this study, as the sample size is too small to conduct analyses based 
on age, sex, race/ethnicity, or other demographic characteristic(s). 
 
10 SUPPORTING DOCUMENTATION AND OPERATIONAL CONSIDERATIONS 
 
10.1 REGULATORY, ETHICAL, AND STUDY OVERSIGHT CONSIDERATIONS 
 
10.1.1 INFORMED CONSENT PROCESS 
 
10.1.1.1 CONSENT/ASSENT AND OTHER INFORMATIONAL DOCUMENTS PROVIDED TO 
PARTICIPANTS 
 
/v(}u}vv]}Z]]v]]]}}Z]v]À]µo[P]vP}
v}v]vµZ}µPZ}µZ]v]À]µo[µ˙]]]}vX˘v]À]µ]}v}
benefits of tACS will be provided to the participants and their families. Consent forms describing, in detail, 
the study intervention, device, procedures, and risks are given to the participant and written 
documentation of informed consent is required prior to the administration of any treatment. Electronic 
consent will be documented via REDCap before the initial interview assessments. All consent forms will 
be IRB-approved and updated with any new information as modifications are made throughout the study. 
 
10.1.1.2 CONSENT PROCEDURES AND DOCUMENTATION 
 
During a phone call, the researcher and potential participants will review the clinical trial in its entirety. 
At several intervals during the consent review, the researcher will ask questions that will assess the 
comprehension of the information in the consent. If the participant is unsure or does not know, the 
researcher will return to that section and more carefully explain the information. Participants must 
complete the eConsent documentation via REDCap prior to any additional procedures taking place. If 
needed, the participants will have the opportunity to discuss the study with their surrogates or think about 
it prior to agreeing to participate. Participants will be informed that participation is voluntary and that 
they may withdraw from the study at any time, without prejudice. 
 
At the beginning of the first visit to the lab, participants will sign a physical copy of the consent document 
witnessed by research personnel. A copy of the signed informed consent document will then be given to 
the participant for their records. The rights and welfare of the participant will be protected by emphasizing 
to them that the quality of their medical care will not be adversely affected if they decline to participate 
in this study 

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10.1.2 STUDY DISCONTINUATION AND CLOSURE 
 
This study may be temporarily suspended or prematurely terminated if there is sufficient reasonable 
cause. If the study is prematurely terminated or suspended, the Principal Investigator (PI) will promptly 
inform research staff, study participants, and the IRB and will provide the reason(s) for the termination or 
suspension.  Study participants will be contacted, as applicable, and be informed of changes to study visit 
schedule.   
 
Circumstances that may warrant termination or suspension include, but are not limited to: 
x 
Determination of unexpected, significant, or unacceptable risk to participants 
x 
Insufficient compliance to protocol requirements 
x 
Data that are not sufficiently complete and/or evaluable 
 
Study may resume once concerns about safety, protocol compliance, and data quality are addressed, and 
satisfy the IRB. 
 
10.1.3 CONFIDENTIALITY AND PRIVACY  
 
Participant confidentiality and privacy is strictly held in trust by the participating investigators, their staff, 
and the research team. This confidentiality is extended to cover testing of biological samples and genetic 
tests in addition to the clinical information relating to participants. Therefore, the study protocol, 
documentation, data, and all other information generated will be held in strict confidence.   
 
All research activities will be conducted in as private a setting as possible. 
 
All data will only be referenced by dummy identifier code. Data will be stored on a password protected 
computer. A key connecting names and identifier code numbers will be kept in a locked cabinet, accessible 
only by research personnel. All data will be stored and analyzed on password protected computers, also 
only accessible by research personnel. Participants will not be identified in any report or publication about 
this study and there is no risk of deductive disclosure. At the end of the study, all records will continue to 
be kept in a secure location for as long a period as dictated by the IRB. 
 
Study participant research data, which is for purposes of statistical analysis and scientific reporting, will 
be entered into TraCS Clinical Research Data Management Service (REDCap). The database system 
provides secure web-based data entry with the data stored on servers that are maintained by TrACS. The 
data is encrypted during transmission. The servers are located in a secure campus area with all appropriate 
physical security measures in place. The web and database servers are monitored by the TraCS IT staff, 
patched frequently, and scanned by a third-party vendor to ensure that they are protected against known 
vulnerabilities. The scanning application is the standard service for the entire campus. Access is by 
individual user id and is restricted to the forms and/or functions that the user needs to have.   
 
10.1.4 FUTURE USE OF STORED SPECIMENS AND DATA  
 
Data collected for this study will be analyzed and stored within the Carolina Center for 
Neurostimulation/Frohlich Lab. After the study is completed, the data will be fully de-identified and 

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archived within a locked file cabinet or an encrypted server maintained by the Carolina Center for 
Neurostimulation. 
 
10.1.5 KEY ROLES AND STUDY GOVERNANCE 
 
Principal Investigator 
Co-Investigator 
Co-Investigator 
Flavio Frohlich, PhD 
David Rubinow, MD 
 
Crystal Schiller, PhD 
The University of North Carolina 
at Chapel Hill - Department of 
Psychiatry 
 
919-966-4584 
The University of North 
Carolina at Chapel Hill - 
Department of Psychiatry 
 
919-445-0212 
The University of North 
Carolina at Chapel Hill - 
Department of Psychiatry 
 
919-966-4810  
Flavio_Frohlich@med.unc.edu 
David_Rubinow@med.unc.edu 
Crystal_Schiller@med.unc.edu 
  
10.1.6 SAFETY OVERSIGHT 
  
Safety oversight will be under the direction of the principal investigator and co-investigators composed of 
three clinical researchers. The PI and/or Co-I will review AEs in real time and make decisions as of 
]]v[
s continuation of the clinical trial. The PI will review AEs as appropriate, every three months at 
a minimum, with the research team. The PI may request additional review by Co-I on a case-by-case basis.  
  
10.1.7 CLINICAL MONITORING 
 
The purpose of the monitoring plan is to present the approach of the Carolina Center for Neurostimulaton 
to monitoring clinical trials.  The plan facilitates compliance with good clinical practice. 
 
(a) The rights and well-being of human participants are protected. 
(b) The reported trial data are accurate, complete, and verifiable from source documents. 
(c) The conduct of the trial is in compliance with the currently approved protocol/amendment(s), with 
GCP, and with applicable regulatory requirement(s). 
 
This section identifies key monitoring activities and specifies the data to be reviewed over the course of a 
clinical trial.  This is a single site, investigator initiated, clinical trial so there will be no site monitoring plan 
in place. 
 
 
10.1.7.1 THE CAROLINA CENTER FOR NEUROSTIMULATION MONITORING PLAN 
 
The latest version of the approved IRB application for this clinical trial will be followed at all times. This 
responsibility falls in the hands of the trained research personnel.  If at any time there is a deviation from 
protocol, the deviation from protocol log will be filled out.  All team members will be trained on how and 
when to use this log. Deviations will be sent to IRB every 4-6 weeks (if necessary). 
 

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Data will be verified for completeness following every study session and all data will be entered into 
REDCap, a secure online database. After a participant has completed their participation (full completion 
through the 2-week follow-up visit or because they withdrew prior to completion), data will be rereviewed 
for completeness and accuracy. After all data has been collected, data will be re-reviewed by another lab 
member who was not involved with the data collection process.  
 
AE and SAE are clearly defined in the Master Protocol. Documents of AE and SAE can be found in the study 
binder on file within Medical School Wing C, Room 233.  It is responsibility of trained research personnel 
to report all events to the PI. Reporting of AEs and SAEs is described within Section 8.3. 
 
The PI and Co-I will have read-only access to the REDCap database.  This allows the PI and Co-I to view 
reports that provide information on any missing data on an individual participant basis, but does not allow 
them to add, change or input any data. 
  
10.1.8 QUALITY ASSURANCE AND QUALITY CONTROL 
 
The Carolina Center for Neurostimulation will conduct internal quality management of study conduct, 
data and biological specimen collection, documentation and completion. Following written Standard 
Operating Procedures (SOPs), research personnel will verify that the clinical trial is conducted and data 
are generated, documented (recorded), and reported in compliance with the protocol, International 
Conference on Harmonisation Good Clinical Practice (ICH GCP), and applicable regulatory requirements 
(e.g., Good Laboratory Practices (GLP), Good Manufacturing Practices (GMP)). 
 
10.1.9 DATA HANDLING AND RECORD KEEPING  
 
10.1.9.1 DATA COLLECTION AND MANAGEMENT RESPONSIBILITIES  
 
Trained research personnel will be responsible for the informed consent process, review for eligibility, 
questionnaire administration, data entry, device administration, EEG administration, and CRF entries. 
Research personnel will be responsible for AE/SAE documentation and reporting, while the PI will be 
responsible for the AE assessment, review of the AE documentation forms and overview of the research 
staff. 
 
Clinical data (including AEs, concomitant medications, and expected adverse reactions data) will be 
entered into a data capture system provided by TraCS Clinical Research Data Management Service 
(REDCap). The data system includes password protection and internal quality checks, such as automatic 
range checks, to identify data that appear inconsistent, incomplete, or inaccurate. Clinical data will be 
entered directly from the source documents. Trained research personnel will have complete access to the 
REDCap system, while the PI and Co-I will have read-only ability. This will enable the researchers to enter 
the data and the PI and Co-I to review. The REDCap data management system will be programmed and 
overseen by Justin Riddle. 
 
As discussed in Section 10.1.3, data entered into REDCap is stored on servers that are maintained by 
TrACS. The data is encrypted during transmission. The servers are located in a secure campus area with 
all appropriate physical security measures in place. The web and database servers are monitored by the 

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TraCS IT staff, patched frequently, and scanned by a third-party vendor to ensure that they are protected 
against known vulnerabilities. The scanning application is the standard service for the entire campus.  
 
10.1.9.2 STUDY RECORDS RETENTION  
  
Ac}]vP}Zhv]À]˙}(E}Z}o]vZo,]oo[Z]ÀvZ}D
schedule for General Records Retention and Disposition Schedule, records will be kept for 5 years after 
the completion of the study or grant end date, whichever is later. 
 
10.1.10 PROTOCOL DEVIATIONS  
  
All deviations from the protocol will be addressed in study participant source documents. The researcher 
will complete a Protocol Deviation Log using the participant code as the identifier. This form will collect 
information such as the date the deviation occurred, details of what the deviation consisted of, any 
corrective and preventative actions that were taken as a result of the deviation, and the date that the PI 
and IRB were notified. The PI will review the information and initial once approved. A completed copy of 
the Protocol Deviation Form will be maintained in the regulatory file, as well as in the participant[}µ
document.  Protocol deviations will be sent to the IRB per their guidelines.  The site PI/study staff will be 
responsible for knowing and adhering to their IRB requirements. 
 
10.1.11 PUBLICATION AND DATA SHARING POLICY 
This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded 
Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. As 
such, this trial will be registered at ClinicalTrials.gov, and results information from this trial will be 
submitted to ClinicalTrials.gov. In addition, every attempt will be made to publish results in peer-reviewed 
journals. 
 
 
10.1.12 CONFLICT OF INTEREST POLICY 
 
The independence of this study from any actual or perceived influence is critical. Any conflict of interest 
for any persons who have a role in the design, conduct, analysis, publication, or any aspect of this trial will 
be disclosed and managed by the UNC Conflict of Interest Office. If necessary, for persons who have a 
perceived conflict of interest, management will be provided again by the UNC Conflict of Interest office. 
 
10.2 
ADDITIONAL CONSIDERATIONS 
 N/A 
 
 
 

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10.3 
ABBREVIATIONS 
The list below includes abbreviations utilized in this template.  However, this list should be customized for 
each protocol (i.e., abbreviations not used should be removed and new abbreviations used should be added 
to this list). 
 
AE 
Adverse Event/Adverse Experience 
ANOVA 
Analysis of Variance 
BDI-II 
l[]}v/vÀv}˙s]}vî
 
BIS/BAS 
Behavioral Inhibition System / Behavioral Approach System 
BRIC 
Biomedical Research Imaging Center 
CFR 
Code of Federal Regulations 
Co-I 
Co-Investigator 
CRF 
Case Report Form 
C-SSRS 
Columbia Suicide Severity Rating Scale 
DHHS 
Department of Health and Human Services 
dlPFC-dSTR 
Dorsolateral prefrontal cortex to dorsal striatum 
DMV 
Department of Motor Vehicles 
DSM-5 
Diagnostic and Statistical Manual of Mental Disorders, 5th Edition 
EEfRT 
Expenditure of Effort for Reward Task 
EEG 
Electroencephalogram 
EMG 
Electromyography 
FDA 
Food and Drug Administration 
fMRI 
Functional magnetic resonance imaging 
GCP 
Good Clinical Practice 
HAM-D 
Hamilton Depression Rating Scale 
HD-EEG 
High-density electroencephalography 
Hz 
Hertz 
ICF 
Informed Consent Form 
IDE 
Investigational Device Exemption 
LAR 
Legally Authorized Representative 
mA 
Milliamperes 
MDD 
Major depressive disorder 
MINI 
Mini International Neuropsychiatric Interview 
mPFC-vSTR 
Medial prefrontal cortex to ventral striatum 
MSM 
Maudsley Staging Method 
MRI 
Magnetic Resonance Imaging 
NIH 
National Institutes of Health 
NIMH 
National Institute of Mental Health 
NSR 
Non-significant risk 
OHRE 
Office of Human Research Ethics 
OHRP 
Office for Human Research Protections 
PAC 
Phase-amplitude coupling 
PHI 
Protected Health Information 
PHQ-9 
Patient Health Questionnaire with 9 items 
PI 
Principal Investigator 
RDoC 
Research domain criteria 
RRS 
Ruminative responses scale 
SAE 
Serious Adverse Event/Serious Adverse Experience 
SHAPS 
Snaith-Hamilton Pleasure Scale 

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SMC 
Safety Monitoring Committee 
SOP 
Standard Operating Procedure 
STAI 
State-Trait Anxiety Inventory 
tACS 
Transcranial Alternating Current Stimulation 
TEPS 
Temporal Experience of Pleasure Scale 
UE 
Unexpected Event 
UNC 
University of North Carolina 
UNC-CH 
University of North Carolina at Chapel Hill 
US 
United States 
 
 
 

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10.4 
PROTOCOL AMENDMENT HISTORY 
  
MAINTAINED AT THE TOP OF THIS DOCUMENT 
 
 

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11 
REFERENCES   
Ahn, S., J. M. Mellin, S. Alagapan, M. L. Alexander, J. H. Gilmore, L. F. Jarskog and F. Frohlich (2018). "Targeting 
reduced neural oscillations in patients with schizophrenia by transcranial alternating current stimulation." 
Neuroimage. 
Alexander, M. L., S. Alagapan, C. E. Lugo, J. M. Mellin, C. Lustenberger, D. R. Rubinow and F. Frohlich (2019). 
"Double-blind, randomized pilot clinical trial targeting alpha oscillations with transcranial alternating current 
stimulation (tACS) for the treatment of major depressive disorder (MDD)." Transl Psychiatry 9(1): 106. 
Ali, M. M., K. K. Sellers and F. Frohlich (2013). "Transcranial alternating current stimulation modulates large-scale 
cortical network activity by network resonance." J Neurosci 33(27): 11262-11275. 
Antal, A., I. Alekseichuk, M. Bikson, J. Brockmoller, A. R. Brunoni, R. Chen, L. G. Cohen, G. Dowthwaite, J. Ellrich, A. 
Floel, F. Fregni, M. S. George, R. Hamilton, J. Haueisen, C. S. Herrmann, F. C. Hummel, J. P. Lefaucheur, D. 
Liebetanz, C. K. Loo, C. D. McCaig, C. Miniussi, P. C. Miranda, V. Moliadze, M. A. Nitsche, R. Nowak, F. Padberg, A. 
Pascual-Leone, W. Poppendieck, A. Priori, S. Rossi, P. M. Rossini, J. Rothwell, M. A. Rueger, G. Ruffini, K. Schellhorn, 
H. R. Siebner, Y. Ugawa, A. Wexler, U. Ziemann, M. Hallett and W. Paulus (2017). "Low intensity transcranial 
electric stimulation: Safety, ethical, legal regulatory and application guidelines." Clin Neurophysiol 128(9): 1774-
1809. 
Badre, D. and D. E. Nee (2018). "Frontal cortex and the hierarchical control of behavior." Trends in cognitive 
sciences 22(2): 170-188. 
Beck, A. T. and A. Beamesderfer (1974). "Assessment of depression: the depression inventory." Mod Probl 
Pharmacopsychiatry 7(0): 151-169. 
Bonanni, L., F. Gualtieri, D. Lester, G. Falcone, A. Nardella, A. Fiorillo and M. Pompili (2019). "Can anhedonia be 
considered a suicide risk factor? A review of the literature." Medicina 55(8): 458. 
Buzsáki, G., C. A. Anastassiou and C. Koch (2012). "The origin of extracellular fields and currentsv EEG, ECoG, LFP 
and spikes." Nature reviews neuroscience 13(6): 407-420. 
Canolty, R. T. and R. T. Knight (2010). "The functional role of cross-frequency coupling." Trends in cognitive 
sciences 14(11): 506-515. 
Carver, C. S. and T. L. White (1994). "Behavioral inhibition, behavioral activation, and affective responses to 
impending reward and punishment: the BIS/BAS scales." Journal of personality and social psychology 67(2): 319. 
Donaldson, A. F. S. W. C., K. M. B. M. L. Poon and A. J. Cleare (2009). "A multidimensional tool to quantify 
treatment resistance in depression: the Maudsley staging method." The Journal of clinical psychiatry 70(2): 177-
184. 
Downar, J., J. Geraci, T. V. Salomons, K. Dunlop, S. Wheeler, M. P. McAndrews, N. Bakker, D. M. Blumberger, Z. J. 
Daskalakis and S. H. Kennedy (2014). "Anhedonia and reward-circuit connectivity distinguish nonresponders from 
responders to dorsomedial prefrontal repetitive transcranial magnetic stimulation in major depression." Biological 
psychiatry 76(3): 176-185. 
Drysdale, A. T., L. Grosenick, J. Downar, K. Dunlop, F. Mansouri, Y. Meng, R. N. Fetcho, B. Zebley, D. J. Oathes and 
A. Etkin (2017). "Resting-state connectivity biomarkers define neurophysiological subtypes of depression." Nature 
medicine 23(1): 28. 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
15 Sept 2021 
 
NIH-FDA Clinical Trial Protocol Template t v1.0 7 Apr 2017 
 
42 
Duprat, R., G.-R. Wu, R. De Raedt and C. Baeken (2018). "Accelerated iTBS treatment in depressed patients 
differentially modulates reward system activity based on anhedonia." The World Journal of Biological Psychiatry 
19(7): 497-508. 
Epstein, J., H. Pan, J. H. Kocsis, Y. Yang, T. Butler, J. Chusid, H. Hochberg, J. Murrough, E. Strohmayer and E. Stern 
(2006). "Lack of ventral striatal response to positive stimuli in depressed versus normal subjects." American Journal 
of Psychiatry 163(10): 1784-1790. 
Fox, M. D., R. L. Buckner, M. P. White, M. D. Greicius and A. Pascual-Leone (2012). "Efficacy of transcranial 
magnetic stimulation targets for depression is related to intrinsic functional connectivity with the subgenual 
cingulate." Biological psychiatry 72(7): 595-603. 
Fries, P. (2015). "Rhythms for Cognition: Communication through Coherence." Neuron 88(1): 220-235. 
Frohlich, F. and D. A. McCormick (2010). "Endogenous electric fields may guide neocortical network activity." 
Neuron 67(1): 129-143. 
Gard, D. E., M. G. Gard, A. M. Kring and O. P. John (2006). "Anticipatory and consummatory components of the 
experience of pleasure: a scale development study." Journal of research in personality 40(6): 1086-1102. 
Greenberg, T., H. W. Chase, J. R. Almeida, R. Stiffler, C. R. Zevallos, H. A. Aslam, T. Deckersbach, S. Weyandt, C. 
Cooper and M. Toups (2015). "Moderation of the relationship between reward expectancy and prediction error-
related ventral striatal reactivity by anhedonia in unmedicated major depressive disorder: Findings from the 
EMBARC study." American Journal of Psychiatry 172(9): 881-891. 
Hamilton, M. (1960). "A rating scale for depression." Journal of neurology, neurosurgery, and psychiatry 23(1): 56. 
Hatzigiakoumis, D. S., G. Martinotti, M. Di Giannantonio and L. Janiri (2011). "Anhedonia and substance 
dependence: clinical correlates and treatment options." Frontiers in psychiatry 2: 10. 
Helfrich, R. F., M. Huang, G. Wilson and R. T. Knight (2017). "Prefrontal cortex modulates posterior alpha 
oscillations during top-down guided visual perception." Proceedings of the National Academy of Sciences 114(35): 
9457-9462. 
Höflich, A., P. Michenthaler, S. Kasper and R. Lanzenberger (2019). "Circuit mechanisms of reward, anhedonia, and 
depression." International Journal of Neuropsychopharmacology 22(2): 105-118. 
Husain, M. and J. P. Roiser (2018). "Neuroscience of apathy and anhedonia: a transdiagnostic approach." Nature 
Reviews Neuroscience 19(8): 470-484. 
Konstantinou, G. N., S. N. Vigod, S. Mehta, Z. J. Daskalakis and D. M. Blumberger (2020). "A systematic review of 
non-invasive neurostimulation for the treatment of depression during pregnancy." Journal of affective disorders. 
Krepel, N., A. J. Rush, T. A. Iseger, A. T. Sack and M. Arns (2020). "Can psychological features predict antidepressant 
response to rTMS? A DiscoverytReplication approach." Psychological medicine 50(2): 264-272. 
Kring, A. M. and D. M. Barch (2014). "The motivation and pleasure dimension of negative symptoms: neural 
substrates and behavioral outputs." European Neuropsychopharmacology 24(5): 725-736. 
Kroenke, K., R. L. Spitzer and J. B. Williams (2001). "The PHQ: 9: validity of a brief depression severity measure." 
Journal of general internal medicine 16(9): 606-613. 
Kurzeck, A. K., B. Kirsch, E. Weidinger, F. Padberg and U. Palm (2018). "Transcranial Direct Current Stimulation 
(tDCS) for depression during pregnancy: scientific evidence and what is being said in the mediav a systematic 
review." Brain sciences 8(8): 155. 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
15 Sept 2021 
 
NIH-FDA Clinical Trial Protocol Template t v1.0 7 Apr 2017 
 
43 
Lambert, C., S. Da Silva, A. K. Ceniti, S. J. Rizvi, G. Foussias and S. H. Kennedy (2018). "Anhedonia in depression and 
schizophrenia: A transdiagnostic challenge." CNS neuroscience & therapeutics 24(7): 615-623. 
Landén, M., P. Högberg and M. E. Thase (2005). "Incidence of sexual side effects in refractory depression during 
treatment with citalopram or paroxetine." The Journal of clinical psychiatry. 
Levkovitz, Y., A. Sheer, E. V. Harel, L. N. Katz, D. Most, A. Zangen and M. Isserles (2011). "Differential effects of 
deep TMS of the prefrontal cortex on apathy and depression." Brain stimulation 4(4): 266-274. 
McMakin, D. L., T. M. Olino, G. Porta, L. J. Dietz, G. Emslie, G. Clarke, K. D. Wagner, J. R. Asarnow, N. D. Ryan and B. 
Birmaher (2012). "Anhedonia predicts poorer recovery among youth with selective serotonin reuptake inhibitor 
treatmenttresistant depression." Journal of the American Academy of Child & Adolescent Psychiatry 51(4): 404-
411. 
Mendez, M. F., N. L. Adams and K. S. Lewandowski (1989). "Neurobehavioral changes associated with caudate 
lesions." Neurology 39(3): 349-349. 
Nierenberg, A. A., B. R. Keefe, V. C. Leslie, J. E. Alpert, J. A. Pava, J. J. Worthington, 3rd, J. F. Rosenbaum and M. 
Fava (1999). "Residual symptoms in depressed patients who respond acutely to fluoxetine." J Clin Psychiatry 60(4): 
221-225. 
Nolen-Hoeksema, S., J. Larson and C. Grayson (1999). "Explaining the gender difference in depressive symptoms." 
Journal of personality and social psychology 77(5): 1061. 
Nusslock, R. and L. B. Alloy (2017). "Reward processing and mood-related symptoms: An RDoC and translational 
neuroscience perspective." Journal of Affective Disorders 216: 3-16. 
K[}Z˙U:XWX~îììðXZ`
presentations and reward-related learning in the human brain: insights from 
neuroimaging." Current opinion in neurobiology 14(6): 769-776. 
Padoa-Schioppa, C. and X. Cai (2011). "Orbitofrontal cortex and the computation of subjective value: consolidated 
concepts and new perspectives." Annals of the New York Academy of Sciences 1239: 130. 
Perera, T., M. S. George, G. Grammer, P. G. Janicak, A. Pascual-Leone and T. S. Wirecki (2016). "The clinical TMS 
society consensus review and treatment recommendations for TMS therapy for major depressive disorder." Brain 
stimulation 9(3): 336-346. 
Pettorruso, M., P. A. Spagnolo, L. Leggio, L. Janiri, M. Di Giannantonio, L. Gallimberti, A. Bonci and G. Martinotti 
(2018). "Repetitive transcranial magnetic stimulation of the left dorsolateral prefrontal cortex may improve 
symptoms of anhedonia in individuals with cocaine use disorder: a pilot study." Brain Stimulation: Basic, 
Translational, and Clinical Research in Neuromodulation 11(5): 1195-1197. 
Pizzagalli, D. A., A. J. Holmes, D. G. Dillon, E. L. Goetz, J. L. Birk, R. Bogdan, D. D. Dougherty, D. V. Iosifescu, S. L. 
Rauch and M. Fava (2009). "Reduced caudate and nucleus accumbens response to rewards in unmedicated 
individuals with major depressive disorder." American Journal of Psychiatry 166(6): 702-710. 
Posner, K., G. K. Brown, B. Stanley, D. A. Brent, K. V. Yershova, M. A. Oquendo, G. W. Currier, G. A. Melvin, L. 
Greenhill and S. Shen (2011). "The ColumbiatSuicide Severity Rating Scale: initial validity and internal consistency 
findings from three multisite studies with adolescents and adults." American journal of psychiatry 168(12): 1266-
1277. 
Riddle, J., A. McFerren and F. Frohlich (2021). "Causal role of cross-frequency coupling in distinct components of 
cognitive control." Progress in Neurobiology: 102033. 

Causal role of delta-beta coupling in anhedonia 
 
V2 
Protocol: 21-1321 
 
15 Sept 2021 
 
NIH-FDA Clinical Trial Protocol Template t v1.0 7 Apr 2017 
 
44 
Riddle, J., D. R. Rubinow and F. Frohlich (2020). "A case study of weekly tACS for the treatment of major depressive 
disorder." Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation 13(3): 576-577. 
Rizvi, S. J., D. A. Pizzagalli, B. A. Sproule and S. H. Kennedy (2016). "Assessing anhedonia in depression: potentials 
and pitfalls." Neuroscience & Biobehavioral Reviews 65: 21-35. 
Sheehan, D. V., Y. Lecrubier, K. H. Sheehan, P. Amorim, J. Janavs, E. Weiller, T. Hergueta, R. Baker and G. C. Dunbar 
(1998). "The Mini-International Neuropsychiatric Interview (MINI): the development and validation of a structured 
diagnostic psychiatric interview for DSM-IV and ICD-10." Journal of clinical psychiatry 59(20): 22-33. 
Shelton, R. C. and A. J. Tomarken (2001). "Can recovery from depression be achieved?" Psychiatric Services 52(11): 
1469-1478. 
Siddiqi, S. H., S. F. Taylor, D. Cooke, A. Pascual-Leone, M. S. George and M. D. Fox (2020). "Distinct symptom-
specific treatment targets for circuit-based neuromodulation." American Journal of Psychiatry: appi. ajp. 
2019.19090915. 
Snaith, R., M. Hamilton, S. Morley, A. Humayan, D. Hargreaves and P. Trigwell (1995). "A scale for the assessment 
of hedonic tone the SnaithtHamilton Pleasure Scale." The British Journal of Psychiatry 167(1): 99-103. 
Spielberger, C. D. (2010). "State: Trait anxiety inventory." The Corsini encyclopedia of psychology: 1-1. 
Sugam, J. A., J. J. Day, R. M. Wightman and R. M. Carelli (2012). "Phasic nucleus accumbens dopamine encodes risk-
based decision-making behavior." Biological psychiatry 71(3): 199-205. 
Szczepanski, S. M. and R. T. Knight (2014). "Insights into human behavior from lesions to the prefrontal cortex." 
Neuron 83(5): 1002-1018. 
Treadway, M. T. and D. H. Zald (2011). "Reconsidering anhedonia in depression: lessons from translational 
neuroscience." Neurosci Biobehav Rev 35(3): 537-555. 
Voytek, B., R. T. Canolty, A. Shestyuk, N. Crone, J. Parvizi and R. T. Knight (2010). "Shifts in gamma phaset
amplitude coupling frequency from theta to alpha over posterior cortex during visual tasks." Frontiers in human 
neuroscience 4: 191. 
Voytek, B., A. S. Kayser, D. Badre, D. Fegen, E. F. Chang, N. E. Crone, J. Parvizi, R. T. Knight and M. D'esposito 
(2015). "Oscillatory dynamics coordinating human frontal networks in support of goal maintenance." Nature 
neuroscience 18(9): 1318-1324. 
Wacker, J., D. G. Dillon and D. A. Pizzagalli (2009). "The role of the nucleus accumbens and rostral anterior 
cingulate cortex in anhedonia: integration of resting EEG, fMRI, and volumetric techniques." Neuroimage 46(1): 
327-337. 
Walsh, E. C., T. A. Eisenlohr-Moul, J. Minkel, J. Bizzell, C. Petty, A. Crowther, H. Carl, M. J. Smoski and G. S. Dichter 
(2019). "Pretreatment brain connectivity during positive emotion upregulation predicts decreased anhedonia 
following behavioral activation therapy for depression." Journal of affective disorders 243: 188-192. 
Wyart, V., V. de Gardelle, J. Scholl and C. Summerfield (2012). "Rhythmic fluctuations in evidence accumulation 
during decision making in the human brain." Neuron 76(4): 847-858. 
Zhang, B., P. Lin, H. Shi, D. Öngür, R. P. Auerbach, X. Wang, S. Yao and X. Wang (2016). "Mapping anhedonia-
specific dysfunction in a transdiagnostic approach: an ALE meta-analysis." Brain imaging and behavior 10(3): 920-
939. 

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