Abnormal small-world architecture of top–down control networks in obsessive–compulsive disorder

Abnormal small-world architecture of top–down control networks in obsessive–compulsive disorder

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J Psychiatry Neurosci 2011;36(1):23-31

Tijiang Zhang, MD; Jinhui Wang, MSc; Yanchun Yang, MD; Qizhu Wu, PhD; Bin Li, MD; Long Chen, MM; Qiang Yue, MD; Hehan Tang, MM; Chaogan Yan, MSc; Su Lui, PhD; Xiaoqi Huang, PhD; Raymond C.K. Chan, PhD; Yufeng Zang, MD; Yong He, PhD; Qiyong Gong, MD, PhD

Zhang, Wu, Chen, Yue, Tang, Lui, Huang, Gong — Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China; Zhang — Department of Radiology, Affiliated Hospital of Zunyi Medical College, Zunyi, China; Wang, Yan, Zang, He — State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China; Yang, Li — Department of Psychiatry, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, China; R.C.K. Chan — Neuropsychology and Applied Cognitive Neuroscience Laboratory & Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; Gong — Division of Medical Imaging, Faculty of Medicine, University of Liverpool, Liverpool, United Kingdom.

Abstract

Background: Obsessive–compulsive disorder (OCD) is a common neuropsychiatric disorder that is characterized by recurrent intrusive thoughts, ideas or images and repetitive ritualistic behaviours. Although focal structural and functional abnormalities in specific brain regions have been widely studied in populations with OCD, changes in the functional relations among them remain poorly understood. This study examined OCD–related alterations in functional connectivity patterns in the brain’s top–down control network.

Methods: We applied resting-state functional magnetic resonance imaging to investigate the correlation patterns of intrinsic or spontaneous blood oxygen level–dependent signal fluctuations in 18 patients with OCD and 16 healthy controls. The brain control networks were first constructed by thresholding temporal correlation matrices of 39 brain regions associated with top–down control and then analyzed using graph theory-based approaches.

Results: Compared with healthy controls, the patients with OCD showed decreased functional connectivity in the posterior temporal regions and increased connectivity in various control regions such as the cingulate, precuneus, thalamus and cerebellum. Furthermore, the brain’s control networks in the healthy controls showed small-world architecture (high clustering coefficients and short path lengths), suggesting an optimal balance between modularized and distributed information processing. In contrast, the patients with OCD showed significantly higher local clustering, implying abnormal functional organization in the control network. Further analysis revealed that the changes in network properties occurred in regions of increased functional connectivity strength in patients with OCD.

Limitations: The patient group in the present study was heterogeneous in terms of symptom clusters, and most of the patients with OCD were medicated.

Conclusion: Our preliminary results suggest that the organizational patterns of intrinsic brain activity in the control networks are altered in patients with OCD and thus provide empirical evidence for aberrant functional connectivity in the large-scale brain systems in people with this disorder.


Submitted Jan. 9, 2010; Revised Apr. 14, 2010; Accepted May 26, 2010.

Acknowledgments: This study was supported by National Natural Science Foundation of China (Grant Nos. 30625024, 81030027, 81030028, 30870667, 30728017 and 30960099), National Basic Research Program (973 Program No: 2007CB512305/2) and National High Technology Program of China (863 Program No: 2008AA02Z408). We thank Zhang John Chen for English editing and proofreading. Dr. Gong also acknowledges his appointment as an Honorary Fellow of the Faculty of Medicine, University of Liverpool, Liverpool, United Kingdom.

Competing interests: None declared.

Contributors: Drs. Zhang, Gong and He contributed to the conception and design of the study and the acquisition, analysis and interpretation of data. Ms. Chen and Tang and Drs. Yang, Wu, Li, Yue, Lui, Huang contributed to the conception and design of the study and the acquisition of data. Ms. Wang and Yan and Drs. Zang and Chan contributed to the conception and design of the study and the analysis of data. Drs. Zhang and He wrote the article, which all other authors reviewed. All authors gave final approval for publication.

DOI: 10.1503/jpn.100006

Correspondence to: Dr. Yong He, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University; yong.he@bnu.edu.cn; or Dr. Qiyong Gong, Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, China; qiyonggong@hmrrc.org.cn