Frontoparietal and salience network alterations in obsessive–compulsive disorder: insights from independent component and sliding time window analyses

Abstract

Background: Resting-state functional MRI (fMRI) studies commonly report alterations in 3 core networks in obsessive-compulsive disorder (OCD) -the frontoparietal network, the default mode network and the salience network -defined by functionally connected infraslow oscillations in ongoing brain activity. However, most of these studies observed static functional connectivity in the brains of patients with OCD. Methods: To investigate dynamic functional connectivity alterations and widen the evidence base toward the triple network model in OCD, we performed group-based independent component and sliding time window analyses in 49 patients with OCD and 41 healthy controls. Results: The traditional independent component analysis showed alterations in the left frontoparietal network as well as between the left and right frontoparietal networks in patients with OCD compared with healthy controls. For dynamic functional connectivity, the sliding time window approach revealed peak dysconnectivity between the left and right frontoparietal networks and between the left frontoparietal network and the salience network. Limitations: The number of independent components, noise in the resting-state fMRI images, the heterogeneity of the OCD sample, and comorbidities and medication status in the patients could have biased the results. Conclusion: Disrupted modulation of these intrinsic brain networks may contribute to the pathophysiology of OCD.

Abnormal dynamics of functional connectivity in first‐episode and treatment‐naive patients with obsessive–compulsive disorder

“…As previous studies did not use the same indicators to assess the dynamic characteristics of functional networks in patients with OCD, direct comparisons between previous findings and ours were excluded. One study of OCD based on dFNC showed more changes during the time course of dynamic functional connection in patients when compared with HC 14 . However, this study did not quantify this dynamic change.…”

“…However, the mechanism involved in the dynamic functional network of OCD in abnormal repetitive behavior and thinking remains unclear. To the best of our knowledge, only one study on dFNC in OCD has been published, which showed more changes in the time course of dynamic functional connection in patients than in healthy controls (HC) 14 . However, this study did not quantify this dynamic change and did not rule out the influence of drug therapy on the results.…”

“…To avoid the influence of psychological intervention or drug therapy on the state of the brain functional network, we recruited first‐episode and treatment‐naive OCD patients as the case group. According to a previous study, 14 we speculated that OCD patients may have abnormal time‐varying characteristics in dFNC. In our study, we aimed to explore the time‐varying characteristics of the whole‐brain functional networks of OCD patients through the analysis of differences in dFNC between OCD patients and HC, so as to expand the neural basis of OCD.…”

“…3,[11][12][13] However, previous rs-fMRI studies have been based on the assumption that brain networks are stationary during the scan, reflecting the functional state by measuring the mean value of a time series over several minutes. 14,15 In fact, this assumption may be outdated in that the pattern of brain activation changes over time. 16 Studies have shown that brain activities are time-dependent and dynamically adaptive to achieve a balance between efficient information processing and metabolic expenditure.…”

“…Current research is more inclined to support that OCD is a brain network disease with extensive brain network abnormalities, which are closely related to clinical symptoms 3,11–13 . However, previous rs‐fMRI studies have been based on the assumption that brain networks are stationary during the scan, reflecting the functional state by measuring the mean value of a time series over several minutes 14,15 . In fact, this assumption may be outdated in that the pattern of brain activation changes over time 16 .…”