Application of Graph Theory Across Multiple Frequency Bands in Obsessive-Compulsive Disorder

Recently, graph theoretical analysis based on resting-state functional magnetic resonance imaging has provided a new means of investigating the complex brain connectome in obsessive-compulsive disorder (OCD) patients. However, these studies have been restricted to spontaneous blood oxygen level-dependent (BOLD) signals with frequency bands between 0.01 and 0.08 Hz, and the parameters from graph theory across multiple frequency bands have seldom been studied. Here, we calculated global metrics (small-worldness, global efficiency and modularity) and nodal metrics (degree centrality, betweenness centrality, nodal clustering coefficient and shortest path) at four different frequency bands (slow-2 (0.199–0.25 Hz), slow-3 (0.074–0.198 Hz), slow-4 (0.027–0.073 Hz) and slow-5 (0.01–0.027 Hz), from 0.01 to 0.25 Hz) in seventy-three OCD patients and 90 healthy controls. The analyses were also calculated in traditional low-frequency bands (0.01–0.08 Hz) for reference. For the global metrics, the OCD patients showed increased small-worldness and modularity only in the slow-3 band. For the local metrics, we observed a frequency-dependent characteristic, with the main significant differences in regions including the right precentral gyrus, occipital region, right anterior cingulum cortex and fusiform cortex. The results suggested frequency-specific abnormalities of the brain connectome in OCD, and future studies should take the different frequency bands into account when measuring spontaneous activity in the brain. Funding Information: This study was supported by the National Key Technologies R&D Program of China (Grant No. 82027808) and the Key Research Project of Sichuan Science and Technology Department (Grant No. 2020YFS0048). Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: This study was approved by the Ethics Committee of the West China Hospital, Sichuan University, and all the participants signed an informed consent form.