Modulating Default Mode Network Function: A Transcranial Direct Current Stimulation (TDCS) Pilot Study

Study Overview
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Brief Summary
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The primary purpose of this research is to gather scientific information about how different people's brains work when they look at different types of pictures. This will help to improve the investigators' understanding of the way the brain works for people who are depressed or anxious, and this knowledge could help lead to better diagnosis and treatment.

Detailed Description
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In this study the investigators are examining the effects of weak electrical stimulation on brain activity as measured by functional magnetic resonance imaging (fMRI). MRI is a widely used method to obtain high resolution brain pictures that are routinely used for diagnostic and clinical purposes. The electrical stimulation is applied on the scalp with a non-FDA approved method called tDCS (transcranial Direct Current Stimulation), typically equivalent to what a 6V battery would produce (and up to no more than 15V). To compare, an AA battery delivers current at 1.5 volt. While almost unnoticeable to the participants, these currents can still temporarily affect brain activity without causing adverse effects. This stimulation would be applied while the participants are in the MRI scanner so that the brain activity can be measured. The participants will have the opportunity to have a test session with the stimulation outside the scanner to get familiar with it.

Official Title
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Modulating Default Mode Network Function: A Transcranial Direct Current Stimulation (TDCS) Pilot Study

Conditions
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Depression, Anxiety

Intervention / Treatment
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* Device: TDCS - transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Between 18-30years old Score > 10 on the QIDS or > 60 on the PROMIS-A We will use a flexible extreme groups recruitment strategy to ensure an adequate distribution of ESC scores. We will ensure that at least 62% of the sample will be composed of those scoring .5 SD above or below the mean, as measured by the NEO-PI-R. This value corresponds to the expected values assuming a normal distribution of the trait. Normal or corrected to normal vision with contact lenses Able to provide informed consent in English Right-handed (Annett criteria) Exclusion Criteria: Have a history of head trauma with loss of consciousness. Have a systemic medical illness that may impact fMRI measures of cerebral blood flow. Meet standard exclusion criteria for fMRI scanning (e.g. claustrophobia, cardiac pacemakers, neural pacemakers, surgically implanted metal devices, cochlear implants, metal braces, or other MRI non-safe metal objects in the body). Are pregnant (self report and tested for as part of any scan by the scanning center and not this protocol) Not native English speaking or not fluent Premorbid NAART IQ estimate<85; Visual disturbance (worse than 20/40 Snellen visual acuity) that is not corrected If have visual disturbance, only access to correction with glasses (i.e., no access to contact lenses). Left/mixed handedness (Annett criteria), to ensure a uniform hemispheric dominance for interpretation of neuroimaging data Active suicidal ideation in need of immediate treatment Scoring below the cutoffs on both the QIDS and the PROMIS-A History of alcohol/substance use disorder (including nicotine) and/or illicit substance use (except cannabis) over the last 3 months, determined by the MINI. Lifetime/present cannabis use (non-disordered levels) will be allowed, given its common usage in individuals in this age range. Current or past psychotic-spectrum disorder History of seizures

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: The first part of the study consists of screening procedures that are meant to determine if potential participants are eligible to take part in the remainder of the study. If you qualify to take part in the scanning portion of the study, you will have 2 scanning sessions on separate days approximately a week apart. For each scan session you will undergo a functional Magnetic Resonance Imaging (fMRI) scan that lasts approximately 30 minutes and no more than 1 hour. The total time you will spend for each scan session will be between 1-3 hours. During the scanning session you will receive transcranial direct current stimulation (tDCS). Prior to scanning, sponge-electrodes will be placed on your scalp. These electrodes will be connected to a stimulator. This stimulator will apply weak currents to the brain while the MRI takes pictures of your brain's responses. The stimulation current that you will experience is usually less than a 6-volt battery but may be increased up to 15-volts.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Transcranial Direct Current Stimulation during fMRI<br>Each subject will undergo transcranial direct current stimulation twice while completing a task in the functional magnetic resonance imaging scanner. | Device: TDCS - transcranial direct current stimulation<br>* TDCS involves passing a weak current through the brain. One variant, cathodal TDCS, can be used to temporarily hyperpolarize cortical pyramidal cells, thereby decreasing neuronal connections. TDCS has been explored as a possible treatment for depression, but results to date are mixed. No work has examined whether TDCS can be used in an individually guided manner to target locations in the parietal cortex and alter the patterns of circuitry dysfunction described previously.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood Oxygen Level Dependent (BOLD) Response in the Precuneus During an Emotion Regulation Task Completed During fMRI Scanning. | The investigators will determine the effects of TDCS on BOLD response in the precuneus/posterior cingulate gyrus. The BOLD signal is a measure of regional blood flow in the brain and is used as a proxy for neural activity in specific brain regions. Values below represent pre-post change in BOLD response to the emotion regulation task that participants complete during fMRI scanning. We hypothesize that tDCS applied to the target used in this study will decrease BOLD signal (lower values) during critical components of this task, normalizing function in this region. | 1 week (between baseline and repeat scanning) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Percentage of Patients Who Reported a Side Effect in the Active tDCS Condition But Not the Sham tDCS Condition | Potential side effects (e.g., headaches, dizziness, uncomfortable sensations, etc...) will be assessed after each tDCS and sham-tDCS administration. Side effects were assessed using a standardized form. Count below represents the number of participants who reported a mild or moderate side effect during active tDCS but not sham tDCS. | 30 minutes to 1 hour (the period during which the tDCS device was worn) on each of two scan days |