Studies with treatment-resistant OCD patients indicate that invasive neuromodulation techniques, such as deep brain stimulation (DBS), may improve fronto-limbic circuit function. For instance, one study examining DBS of the ventral anterior limb of the internal capsule (ALIC) in refractory OCD patients reported improvements in OCD symptoms and co-occurring depression and anxiety as well as changes in functional connectivity between the amygdala and vmPFC [67]. Other work has indicated that the bed nucleus of the stria terminalis (BNST), a center of integration for limbic information that is implicated in processing uncertain threat [68], is a potentially efficacious target for OCD symptom improvements [69]. However, other research on DBS in OCD (and other psychiatric disorders) has highlighted that the efficacy of DBS in reducing symptoms may depend less on the gray or white matter stimulation target and more on the white matter networks affected by the stimulation [70–71] (Table 3). Indeed, a recent analysis examining tractography correlates of OCD symptom improvement following DBS targeted at different stimulation sites, including the ALIC, indicated that successful reduction of symptoms was associated with connectivity of
