The symptoms of obsessive-compulsive disorder (OCD) appear linked to dysfunction in a cortico-striato-thalamo-cortical circuit. However, obsessions and compulsions vary widely among OCD patients, suggesting that other symptom-specific brain networks may accompany this core defect. Identifying such networks could lead to personalized treatments, improving upon current one size fits all approaches.~Factor analyses have found distinct symptom dimensions in OCD, but the neural systems specific to these dimensions remain unclear. Using a novel, data-driven, individual-level approach to resting-state functional connectivity magnetic resonance imaging (fcMRI), the investigators have shown that increased connectivity between right medial frontal gyrus (R MFG) and brain regions within the ventral attention network (VAN) - regions critical to reorienting attention in response to relevant external stimuli - specifically predicted the severity of contamination/washing (CONTAM) symptoms, and attenuation of this hyperconnectivity following treatment was associated with improvement in CONTAM symptoms. Based on these findings, the investigators hypothesize that decreasing R MFG-VAN connectivity via transcanial magnetic stimulation (TMS) will normalize attentional reorienting and reduce CONTAM symptoms in individuals with contamination-based OCD.~The investigators propose a two-phase program to investigate R MFG-targeted TMS as a potential intervention for contamination-based OCD. First, in the currently study, the investigators will determine the optimal TMS paradigm to decrease R MFG-VAN connectivity by administering continuous, intermittent, and sham theta burst stimulation (cTBS, iTBS, sham) to individuals with contamination-based OCD using a novel individual-level approach to target the area of R MFG most strongly correlated with VAN based on each participant's pre-treatment connectivity data. Second, the investigators will use the TMS approach identified in this study to test the links between reduced R MFG-VAN connectivity, decreased VAN activation during attentional reorienting, and reduced CONTAM symptoms in a future study using a larger sample of OCD individuals with CONTAM.
Patients with obsessive-compulsive disorder (OCD) experience a wide array of different types of obsessions and compulsions. However, current treatments for OCD employ a one size fits all approach and are used for all patients regardless of symptom type. In this project, the investigators propose to investigate whether a novel method of transcranial magnetic stimulation specifically reduces contamination/washing symptoms - one of the most common types of OCD.