Antidepressant Mechanisms of Transcranial Magnetic Stimulation

This study utilizes resting state fMRI, arterial spin labelling imaging, diffusion tensor imaging, structural MR-imaging, and MR-spectroscopy of GABA and Glutamate to probe the antidepressant mechanisms of repetitive transcranial magnetic stimulation (rTMS). The above imaging modalities will be acquired before and after an open-label 5 week course of rTMS for depression in currently depressed individuals with treatment resistant depression. Changes in functional, structural, and neurochemical markers will be investigated in rTMS responders and nonresponders to elucidate mechanisms of plasticity that correlate with treatment response. Additionally, functional, structural, and neurochemical signatures at baseline that correlate with subsequent treatment response will be investigated.