Cognitive studies in OCD suggest that the parietal cortex plays a significant role in accounting for the cognitive deficits seen in OCD patients. Parietal lobe activation may be related to attention, set shifting, planning and response inhibition, which are also reported to be impaired in OCD patients (34) and reflect a lack of cognitive flexibility that may be related to the repetitive nature of OCD symptoms and behaviors. The inferior parietal cortex is an important node in both the fronto-parietal network and the default mode network. Several studies reported altered connectivity within these networks in patients with OCD (35–37). The phenomenology of the disorder is consistent with the idea of a disrupted relationship between ongoing internal thought and external information, in that patients often excessively focus on internally generated fears that are inconsistent with evidence present in the external environment (38).
