Neuromodulation techniques (Table 3) may offer a more direct method of targeting fronto-limbic dysfunction. A sham-controlled study with OCD patients showed that high-frequency repetitive transcranial magnetic stimulation (rTMS) of the left dlPFC reduced both fear distress ratings and neural activity in the amygdala and other visual emotion processing areas and altered functional connectivity between the amygdala and dmPFC during a fear/OCD provocation task [60]. Another sham-controlled study in patients with generalized anxiety disorder showed that low-frequency (inhibitory) rTMS of the right dlPFC normalized atypical dlPFC-amygdala functional connectivity that was induced by uncertainty during a gambling task designed to elicit IU [61]. The finding that both high [60] and low [61] frequency rTMS resulted in improved fronto-limbic circuit function may seem contradictory since these protocols are hypothesized to have opposite effects on neural plasticity (see Table 3). Yet, this is consistent with findings from a recent systematic review and meta-analysis [62] of 18 randomized controlled trials (RCTs) evaluating the efficacy of rTMS for OCD, which showed that low-frequency and high-frequency rTMS were both superior to sham in improving OCD symptoms. Finally,
