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.