Does rTMS Induce Synaptic Plasticity?

The objective of this project is to discover the neural mechanisms by which Major Depressive Disorder (MDD) is treated, so that we may gain insights into its pathophysiology, as well as to develop new biomarkers. We will utilize the PET tracer \[11C\]UCB-J, the first in human tracer of neural synapses, to test the hypothesis that the successful treatment of MDD with repetitive Transcranial Magnetic Stimulation (rTMS) is associated with increased synaptic density. We will use this tracer to measure synaptic density before and after rTMS treatment and compare change in synaptic density between subjects who respond to the rTMS treatment and those who do not respond to treatment. The finding of a marked increase in synaptic density in participants who respond to rTMS treatment would point to the possibility of developing new treatments with the potential to modify disease through mitigating, preventing or remediating synaptic loss.