To explore the differences of the resting-state functional connectivity(FC) between goal-directed network and habituation networks in patients with early- and late-onset obsessive compulsive disorder (OCD) and the correlation between the strength of FC in the differential brain regions and cognitive flexibility.

From October 2019 to April 2021, 40 patients with OCD were included in this study, including 22 patients with early-onset OCD and 18 patients with late-onset OCD.The cognitive flexibility of all subjects was assessed using the Wisconsin card sorting test (WCST), the Stroop task and the trail making test (TMT). The brain regions which were associated with goal-directed network(caudate, orbitofrontal cortex, ventromedial prefrontal cortex, and anterior cingulate cortex) and the brain regions which were associated with habituation network(putamen, supplementary motor area and insula) were selected as FC regions of interest (ROI). The DPABI and SPM12 plug-ins in the matlab2011a platform were used for whole brain FC analysis to compare the difference of FC between patients with early-onset OCD and patients with late-onset OCD on the two networks.The data were analyzed by SPSS 25.0 with χ² test, independent samples t-test, and Pearson correlation analysis.

Compared with patients with early-onset OCD, patients with late-onset OCD had significantly enhanced FC of the left supplementary motor area with the left putamen and left insula.The total number of persistent errors of WCST in patients with late-onset OCD was greater than that in patients with early-onset OCD ((20.61±11.30), (14.95±8.94), P<0.05). The FC of the left putamen-left supplementary motor area was significantly and positively correlated with the total number of sustained responses (r=0.678, P=0.003) and the total number of incorrect responses (r=0.590, P=0.013) in patients with late-onset OCD.The FC of the left supplementary motor area-left insula was significantly positively correlated with the number of responses required to complete the first classification in patients with late-onset OCD (r=0.485, P=0.049).

Patients with late-onset OCD have stronger habituation network FC than patients with early-onset OCD, and the enhanced FC correlates with patients' cognitive flexibility performance, while late-onset OCD has more impaired cognitive flexibility than early-onset OCD.

Early-onset obsessive compulsive disorder; Late-onset obsessive compulsive disorder; Goal-directed networks; Habituation networks; Cognitive flexibility