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

N/AEnrolling By InvitationNCT05853939

Stanford University60 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Visual Cortical Plasticity Repetitive Transcranial Magnetic Stimulation Visual Attention

repetitive transcranial magnetic stimulationDEVICE

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

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

post-rTMS change in ssVEP Response Amplitude

Change in ssVEP contrast-response amplitude after rTMS

Time frame: 60 minutes

post-rTMS change in visual contrast perceptual sensitivity

change in visual psychometric threshold across contrasts after rTMS