Measuring rTMS-induced Neuroplasticity With EEG Steady-state Visual-evoked Potentials

Study Overview
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Brief Summary
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The goals of this study are to 1) use EEG steady-state visual evoked potentials as a noninvasive measure of the neuroplasticity induced by repetitive transcranial magnetic stimulation (rTMS), 2) use visual contrast detection paradigms as a behavioral measure of rTMS effects, and 3) to investigate how visual spatial attention augments or suppresses the neuroplastic impact of rTMS. Participants will observe visual stimuli on a screen while allocating their attention to different parts of the visual field and making responses when they observe changes in the visual stimuli. rTMS is performed to visual cortex using MRI-retinotopy neuronavigation. Then the visual task paradigm is performed again.

Official Title
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Inducing and Measuring Visual-evoked Potential Plasticity in Humans With Repetitive Transcranial Magnetic Stimulation

Conditions
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Visual Cortical Plasticity, Repetitive Transcranial Magnetic Stimulation, Visual Attention

Intervention / Treatment
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* Device: repetitive transcranial magnetic stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women, ages 18 to 65 Must comprehend English well to ensure adequate comprehension of the EEG and TMS instructions, and of clinical scales Left- or Right-handed No current or history of neurological disorders No seizure disorder or risk of seizures Exclusion Criteria: Those with a contraindication for MRIs (e.g. implanted metal) Any unstable medical condition History of head trauma with loss of consciousness History of seizures Neurological or uncontrolled medical disease Active substance abuse Diagnosis of psychotic or bipolar disorder Currently taking medications that substantially reduce seizure threshold (e.g., bupropion, olanzapine, chlorpromazine, lithium) Currently pregnant or breastfeeding

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: Cross-over: 1 Hz vs 10 Hz vs sham rTMS; stimulation to attended or unattended hemisphere
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Visual Cortex, 1 Hz rTMS, Attended<br> | Device: repetitive transcranial magnetic stimulation<br>* Repetitive TMS targeted by neuronavigation to left lower visual field of primary visual cortex. Randomized to 10 Hz or 1 Hz on different treatment days. Stimulation at 110% of phosphene threshold, or 110% resting motor threshold if phosphenes not detectable. 1 Hz: 1000 pulses total over 1000 seconds. 10 Hz: 1000 pulses over 10 10 second pulse trains, with 50 second intertrain intervals<br>|
| Experimental: Visual Cortex, 1 Hz rTMS, Unattended<br> | Device: repetitive transcranial magnetic stimulation<br>* Repetitive TMS targeted by neuronavigation to left lower visual field of primary visual cortex. Randomized to 10 Hz or 1 Hz on different treatment days. Stimulation at 110% of phosphene threshold, or 110% resting motor threshold if phosphenes not detectable. 1 Hz: 1000 pulses total over 1000 seconds. 10 Hz: 1000 pulses over 10 10 second pulse trains, with 50 second intertrain intervals<br>|
| Experimental: Visual Cortex, 10 Hz rTMS, Attended<br> | Device: repetitive transcranial magnetic stimulation<br>* Repetitive TMS targeted by neuronavigation to left lower visual field of primary visual cortex. Randomized to 10 Hz or 1 Hz on different treatment days. Stimulation at 110% of phosphene threshold, or 110% resting motor threshold if phosphenes not detectable. 1 Hz: 1000 pulses total over 1000 seconds. 10 Hz: 1000 pulses over 10 10 second pulse trains, with 50 second intertrain intervals<br>|
| Experimental: Visual Cortex, 10 Hz rTMS, Unattended<br> | Device: repetitive transcranial magnetic stimulation<br>* Repetitive TMS targeted by neuronavigation to left lower visual field of primary visual cortex. Randomized to 10 Hz or 1 Hz on different treatment days. Stimulation at 110% of phosphene threshold, or 110% resting motor threshold if phosphenes not detectable. 1 Hz: 1000 pulses total over 1000 seconds. 10 Hz: 1000 pulses over 10 10 second pulse trains, with 50 second intertrain intervals<br>|
| Sham Comparator: Visual Cortex, Sham, Attended<br> | Device: repetitive transcranial magnetic stimulation<br>* Repetitive TMS targeted by neuronavigation to left lower visual field of primary visual cortex. Randomized to 10 Hz or 1 Hz on different treatment days. Stimulation at 110% of phosphene threshold, or 110% resting motor threshold if phosphenes not detectable. 1 Hz: 1000 pulses total over 1000 seconds. 10 Hz: 1000 pulses over 10 10 second pulse trains, with 50 second intertrain intervals<br>|
| Sham Comparator: Visual Cortex, Sham, Unattended<br> | Device: repetitive transcranial magnetic stimulation<br>* Repetitive TMS targeted by neuronavigation to left lower visual field of primary visual cortex. Randomized to 10 Hz or 1 Hz on different treatment days. Stimulation at 110% of phosphene threshold, or 110% resting motor threshold if phosphenes not detectable. 1 Hz: 1000 pulses total over 1000 seconds. 10 Hz: 1000 pulses over 10 10 second pulse trains, with 50 second intertrain intervals<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| post-rTMS change in ssVEP Response Amplitude | Change in ssVEP contrast-response amplitude after rTMS | 60 minutes | 
| post-rTMS change in visual contrast perceptual sensitivity | change in visual psychometric threshold across contrasts after rTMS | 60 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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visual-evoked potentials, TMS, neuroplasticity