Inhibitory Control: Effects of Modulation

Study Overview
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Brief Summary
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Inhibitory control is relevant to many clinical disorders, including substance abuse/dependence, obsessive-compulsive disorder, and attention-deficit hyperactivity disorder. This proposal is designed to assess brain networks related to response inhibition in healthy young adults, and use neuromodulation to change these networks and behavioral performance on a response inhibition task. Having an understanding of the brain mechanisms involved in response inhibition may enable us to improve pre-existing treatments for disorders with inhibitory control difficulties.

Official Title
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Brain Circuitry of Inhibitory Control: Effects of Modulation

Conditions
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Young Adults

Intervention / Treatment
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* Device: Transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Low (<1sd below the mean on the BRIEF-Inhibit) or high (>1sd above the mean on BRIEF-Inhibit scale) English fluency to ensure comprehension of study measures and instructions. Exclusion Criteria: Presence of medical conditions contraindicated for tDCS, including history of any known intracranial pathology, epilepsy or seizures, traumatic brain injury, brain tumor, stroke, implanted medical devices, current pregnancy or women of childbearing age not using effective contraception, or any other serious medical conditions or health problems that would interfere with participation (e.g., skin condition) Inability to undergo MRI Current substance abuse disorder Currently prescribed psychiatric medications. Active mania or psychosis

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: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Cautious Participants<br>Participants who have low scores on a self-report of inhibitory control abilities (BRIEF-Inhibit). | |
| Experimental: Impulsive Participants- Active Stimulation<br>Participants who have high scores on a self-report of inhibitory control abilities (BRIEF-Inhibit) who are randomized to active stimulation. | Device: Transcranial direct current stimulation<br>* 20 minutes of 2 milliamp transcranial direct current stimulation<br>|
| Sham Comparator: Impulsive Participants- Sham Stimulation<br>Participants who have high scores on a self-report of inhibitory control abilities (BRIEF-Inhibit) who are randomized to sham stimulation. | Device: Transcranial direct current stimulation<br>* 20 minutes of 2 milliamp transcranial direct current stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| fMRI connectivity at rest | Changes in resting state connectivity of the inhibitory control information | 2 weeks | 
| fMRI connectivity during a stop signal task | Changes in task-based connectivity on the stop signal task | 2 weeks |