Activating and Identifying Neural Responses to Social Rejection: a Combined tDCS and fMRI Study

Study Overview
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Brief Summary
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This research study identifies neural pathways regulating negative moods during rejection by combining transcranial direct current stimulation (tDCS) and fMRI in a sample of healthy controls.

Detailed Description
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Aim 1: To test the behavioral effects of tDCS during social rejection. The first step will be to obtain behavioral effects of transcranial direct current stimulation (tDCS) during social rejection without functional magnetic resonance imaging (fMRI). Whereas previous studies used Cyberball (a computerized ball-tossing game that simulates social exclusion), we will use the Social Feedback Task. This task was created by Dr. Hsu to be more ethologically-relevant, has been shown to sustain negative moods during rejection and activates the right ventral lateral prefrontal cortex (rVLPFC) (preliminary fMRI data from 50 healthy controls in Dr. Hsu's previous study). Anodal tDCS will be applied over the right or left VLPFC to measure changes in mood during rejection and neutral conditions. Depending on results, alternate regions in separate subjects may also be stimulated: dorsolateral prefrontal cortex, insula, anterior cingulate cortex, pre-supplementary, and supplementary motor area [all regions may be right or left hemisphere]. All of these regions have been shown to be involved in emotion regulation. Questionnaires will be given before, during, and after the task to assess cognitive and emotional states. Aim 2: To identify neural pathways regulating negative moods during social rejection, using tDCS for activation and fMRI for assessment. Using a cross-over, sham-controlled design similar to previous tDCS+fMRI studies, we will measure the effects of anodal tDCS over the right or left VLPFC on neural activity and negative mood during rejection and neutral conditions. Alternate regions in separate subjects may also be stimulated including the dorsolateral prefrontal cortex, insula, anterior cingulate cortex, pre-supplementary, and supplementary motor area [all regions may be right or left hemisphere]. All of these regions have been shown to be involved in emotion regulation.

Official Title
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Activating and Identifying Neural Responses to Social Rejection: a Combined Transcranial Direct Current Stimulation (tDCS) and Functional Magnetic Resonance Imaging (fMRI) Study

Conditions
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Healthy

Intervention / Treatment
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* Device: tDCS
* Device: Sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy males or females between 18 and 25 years old No diagnosis on Axis I by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders IV. No current, or within the past 5 years. Not currently in a romantic relationship Ability to understand and follow instructions and oriented to name, time, and place. No additional neurologic or psychiatric disorders No current use of psychotropic drugs or during past 3 months (except marijuana and alcohol) No current use of marijuana or during past 3 weeks Not currently abusing alcohol No history of alcohol or drug dependence within past 5 years A negative urine pregnancy and toxicology screen. Verbal affirmation will be obtained (i.e., not pregnant and not currently using psychotropic drugs or during the past 3 months) during the Screening Visit (Day 1). Urine screen will be obtained on Days 2 and 3. If subject reports that there is a possibility that she is pregnant on Day 1 (Screening Visit) a urine pregnancy screen will be performed on that day. (Women): If stopped or started oral contraceptives recently, at least 60 days on/off oral contraceptives. Exclusion Criteria: Left-handed or ambidextrous Metallic dental implants Metallic objects in the brain/skull Medical device implants Implanted electronic devices History of seizures History of strokes Unexplained loss of consciousness Frequent or severe headaches or neck pain Clinically significant, uncontrolled liver, kidney, cardiac, or pulmonary disease Terminal medical diagnosis consistent with survival < 1 year Pregnancy; childbirth or miscarriage within 6 months, breastfeeding within 6 months of recruitment Serious mental impairment. Mini mental state exam of < 23/30 Chronic skin disease Previous experience with transcranial direct current stimulation (tDCS) Regular tobacco use or tobacco use within past month If using hormonal birth control, taking progestin-only pills (e.g., Cerazette, Ovrette), or Intrauterine devices (Mirena, Skyla), since progestin-only birth controls are more likely to cause mood swings. Addition Exclusion Criteria for participating in fMRI: Metal anywhere in the body Weight over 250 pounds, or girth size incompatible for scanner bore.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 25 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: within-subjects crossover design
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Sham tDCS<br>tDCS stimulation will be administered over the brain area of interest, but will be shorter in duration than the active treatment | Device: Sham tDCS<br>* Sham tDCS<br>|
| Active Comparator: Active tDCS<br>tDCS stimulation will be administered over the brain area of interest | Device: tDCS<br>* tDCS<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood Oxygen Level Dependent (BOLD) Signal Changes (in Arbitrary Units) | Images from fMRI scans for each participant are preprocessed (e.g., realigned, normalized, smoothed). Changes in BOLD signal are modeled for rejection and acceptance vs neutral blocks, and contrast images are created. These contrast images are used to compare tDCS vs sham for each subject in a within-subjects analysis. BOLD responses are reported as arbitrary units (i.e., change from sham stimulation). Regions of interest include left and right ventrolateral prefrontal cortex (VLPFC), left and right nucleus accumbens (NAcc), left and right amygdala (Amyg), left and right anterior insula (AI), left and right dorsal anterior cingulate cortex (dACC). | 1-3 weeks | 
| Change in Positive and Negative Affect Scale (During fMRI) | Change in emotion will be measured on the Positive and Negative Affect Scale. During Rejection, Acceptance, and Neutral conditions, participants rate how much they feel sad, rejected, happy, and accepted on a visual analog scale from not at all (minimum score of 0) to extremely (maximum score of 100). Scores for sad were averaged with rejected, and scores for happy were averaged with accepted. The averaged scores during Neutral were subtracted from Rejection and Acceptance to derive the outcome measures. Higher outcome measure score means that the participant felt more of that particular emotion during a particular condition (minus neutral). Thus, a higher score for happy and accepted during the Acceptance-Neutral condition means a better outcome. Similarly, a lower score for happy and accepted' during Rejection-Neutral condition means a worse outcome. | 1-3 weeks | 
| Change in the Single-item Self-Esteem Scale (During fMRI) | Change in self-esteem will be measured on the Single-item Self-Esteem Scale. During Rejection, Acceptance, and Neutral conditions, participants respond to the item I have high self-esteem on a visual analog scale from not at all true of me (minimum score of 0) to very true of me (maximum score of 100). Scores during Neutral were subtracted from Rejection and Acceptance to derive the outcome measures. Higher outcome measure score means that the participant had more self-esteem, and thus a better outcome, during a particular condition (minus neutral). | 1-3 weeks | 
| Change in Desire for Social Interaction Scale (During fMRI) | Change in Desire for Social Interaction will be measured on the Desire for Social Interaction Scale. During Rejection, Acceptance, and Neutral conditions, participants respond to four items measuring desire for social interaction (e.g., I would enjoy social interaction right now) on a visual analog scale from very slightly or not at all (minimum score of 0) to extremely (maximum score of 100). Scores during Neutral were subtracted from Rejection and Acceptance to derive the outcome measures. Higher outcome measure score means that the participant had greater desire for social interaction, and thus a better outcome, during a particular condition (minus neutral). | 1-3 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tDCS rejection affect mood fMRI