Menstrual Cycle TMS Plasticity Pilot

DEVICE

transcranial magnetic stimulation

Subjects will receive a series of 60 10s trains that will be presented over the course of the \~3.5 min session. Each train will consist of 2 s of stimulation with an 8 s ITI. During the 2 s of stimulation, 10, 50 Hz bursts will be repeated at intervals of 200 ms (5 Hz). iTBS will be administered at 100% of the motor threshold (MT).

Single-pulse TMS

Time frame: Will be collected during 3 visits over the course of a 2 month timeframe during different phases of the menstrual cycle (in females).

Single-pulse TMS: Cortical excitability curves will be measured before and after a single 1800-pulse train of iTBS. Motor Evoked Potentials (MEPs) will be recorded from the right FDI muscle at 7 distinct intensities ranging from -20% to + 40% of MT. Single pulses will be delivered once every 10±3 seconds to the left motor cortex at random intensities in the above range to avoid habituation across pulses. Across the session, a total of 70 pulses will be delivered before and after iTBS, 10 at each intensity.

Paired pulse stimulation

Time frame: Will be collected during 3 visits over the course of a 2 month timeframe during different phases of the menstrual cycle (in females).

Paired-pulse stimulation: Subjects will undergo paired-pulse stimulation to measure both intracortical inhibition and intracortical facilitation. For intracortical inhibition, subjects will receive a conditioning pulse at 80% MT 4 seconds before the test pulse at 120% MT. For intracortical facilitation, subjects will receive a conditioning pulse at 120% MT 15s before the test pulse at 120% MT. Across the session, a total of 60 paired pulses will be delivered before and after iTBS, 30 at each ISI.

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Will I receive a placebo instead of treatment?

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