State Dependence of Prefrontal Transcranial Magnetic Stimulation

Study Overview
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Brief Summary
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The study will examine whether the benefits of brain stimulation on mental functioning can be enhanced if an individual is actively engaging the target brain networks while receiving brain stimulation. The study includes two separate sessions and people will complete either a cognitive task or a perceptual task while receiving transcranial magnetic stimulation. The study will measure change in brain function with EEG.

Official Title
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State Dependence of Prefrontal Transcranial Magnetic Stimulation

Conditions
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Healthy

Intervention / Treatment
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* Device: Brain state while receiving TMS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18 - 65, healthy controls Exclusion Criteria: Diagnosed psychiatric disorder Potential contraindications to EEG (e.g. visible scalp abrasions, non-removable hair extensions and/or hair styling that would impede proper EEG recording) Potential contraindication to TMS (as identified by the TMS safety screener) Any previous adverse reaction to TMS or MRI Diagnosed epilepsy or previously experienced a seizure Diagnosed neurological condition, such as stroke or tinnitus Experienced a head trauma that was diagnosed as concussion Current use of, or recent withdrawal from, medications that can increase the risk of seizure Currently pregnant Any metal in the head (excluding mouth) Any implanted medical device

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Repeated measures design - across two separate sessions (one week apart, counterbalanced between participants), participants will receive transcranial magnetic stimulation (TMS) whilst engaging in either a cognitive control or a perceptual task.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy control<br>All participants receive the same procedures | Device: Brain state while receiving TMS<br>* Brain state whilst receiving TMS - cognitive control or perceptual. Repeated measures design, so all participants receive the same procedures.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Theta-gamma cross frequency coupling | A metric of brain function measured with EEG - the coupling of theta oscillation phase with gamma power. This will be measured immediately following the intervention (TMS stimulation). | 0-500 ms after each TMS stimulus | 
| Cortical excitability | TMS-evoked potentials will be measured with EEG to examine cortical excitability after TMS. This will be measured immediately following the intervention (TMS stimulation). | 60-300 ms after each TMS stimulus |