Repetitive Transcranial Magnetic Stimulation Equipment Testing and Pilot Study

Objective: To establish an effective repetitive transcranial magnetic stimulation (rTMS) protocol for stimulating circuits relevant for addiction. Specifically, we will develop stimulation parameters and outcome measures for rTMS of the anterior cingulate cortex (ACC) with a specialized TMS coil: the HAC coil (Brainsway Ltd.). Various parameters of rTMS stimulation (frequency and intensity) will be varied, and the sensitivity of behavioral tasks and MRI measures to this stimulation will be determined. The objective of this protocol is therefore to allow for the development, assessment and refinement of rTMS parameters for stimulating ACC targets. In addition, outcome measures will be developed to capture the effects of this stimulation. Results from this development protocol will be applied to subsequent cognitive imaging protocols. Study population: Up to 50 healthy, non-smoking adults will be tested in several conditions over up to two weeks. Subjects must fit exclusion/inclusion criteria for TMS and MRI. We expect 140 subjects to be enrolled to arrive at a number of 50 who complete the protocol. Design: Within-subject design with each subject completing up to 10 rTMS sessions. Outcome measures: In a first phase, the outcome measure will be the behavioral response on a task that relies on the ACC. In a second phase, outcome measures will be the effects on MR measures. These will include task-related blood oxygen level-dependent (BOLD) responses, as well as resting state BOLD functional magnetic resonance imaging (fMRI). Other MR measures, such as magnetic resonance spectroscopy (MRS) and arterial spin labeling (ASL), will also be explored as potential biomarkers.