Distinct functional connectivity of limbic network in the washing type obsessive-compulsive disorder

Neurobiological models of obsessive-compulsive disorder (OCD) emphasize disturbances of the corticostriatal circuit, but it remains unclear as to how these complex network dysfunctions correspond to heterogeneous OCD phenotypes. We aimed to investigate corticostriatal functional connectivity alterations distinct to OCD characterized predominantly by contamination/washing symptoms. Functional connectivity strengths of the striatal seed regions with remaining brain regions during the resting condition and the contamination symptom provocation condition were compared among 13 OCD patients with predominant contamination/washing symptoms (CON), 13 OCD patients without these symptoms (NCON), and 18 healthy controls. The CON group showed distinctively altered functional connectivity between the ventral striatum and the insula during both the resting and symptom-provoking conditions. Also, the connectivity strength between the ventral striatum and the insula significantly correlated with contamination/washing symptom severity. As common connectivity alterations of the whole OCD subjects, corticostriatal circuits involving the orbitofrontal and temporal cortices were again confirmed. To our knowledge, this is the first study that examined specific abnormalities in functional connectivity of contamination/washing symptom dimension OCD. The findings suggest limbic network dysfunctions to play a pivotal role in contamination/washing symptoms, possibly associated with emotionally salient error awareness. Our study sample allowed us to evaluate the corticostriatal network dysfunction underlying the contamination/washing symptom dimension, which leaves other major symptom dimensions to be explored in the future.