Repeated iTBS Cycloserine Motor Plasticity

Repetitive transcranial magnetic stimulation (rTMS) is a modality for probing and altering brain function in humans non-invasively. The technology relies on the principles of electromagnetic induction, whereby magnetic fields have an associated electrical field. By intersecting two magnetic fields safely generated outside the head, one can induce a focal electrical current where the magnetic fields intersect in the brain, and this can depolarize cell membranes and impact brain activity. A well investigated phenomenon in neuroscience is the principle of long term potentiation (LTP), and its converse long term depression (LTD), referring to the ability of neurons to increase or decrease their connection strength in an activity dependent manner. They do this through modifications to their electrochemical junctions, the synapses. We have previously used the motor system as a model system to study the impact D-Cycloserine, an NMDA receptor partial agonist, on synaptic plasticity after TMS. Conventional therapeutic TMS is delivered once daily, however it is increasingly being delivered multiple times per day in an effort to speed treatment effects. It is unclear how adjunctive agents would impact these repeated stimulation designs. Research Question: Does the N-methyl-D-aspartate receptor partial agonist D-Cycloserine stabilize motor plasticity across multiple daily sessions of TMS?