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Schizophr Res. 2016 Jan;170(1):55-65. doi: 10.1016/j.schres.2015.11.021. Epub 2015 Dec 3.

Interaction among subsystems within default mode network diminished in schizophrenia patients: A dynamic connectivity approach.

Author information

1
The Mind Research Network & LBERI, Albuquerque, NM, USA; School of Information and Communication Engineering, North University of China, Taiyuan, China. Electronic address: ydu@mrn.org.
2
Department of Psychiatry, Yale University, New Haven, CT, USA; Department of Neurobiology, Yale University, New Haven, CT, USA; Olin Neuropsychiatry Research Center, Institute of Living, Hartford, CT, USA.
3
The Mind Research Network & LBERI, Albuquerque, NM, USA.
4
The Mind Research Network & LBERI, Albuquerque, NM, USA; Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, USA.
5
The Mind Research Network & LBERI, Albuquerque, NM, USA; Brainnetome Center and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.
6
The Mind Research Network & LBERI, Albuquerque, NM, USA; Department of Psychiatry, Yale University, New Haven, CT, USA; Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, USA.

Abstract

Default mode network (DMN) has been reported altered in schizophrenia (SZ) using static connectivity analysis. However, the studies on dynamic characteristics of DMN in SZ are still limited. In this work, we compare dynamic connectivity within DMN between 82 healthy controls (HC) and 82 SZ patients using resting-state fMRI. Firstly, dynamic DMN was computed using a sliding time window method for each subject. Then, the overall connectivity strengths were compared between two groups. Furthermore, we estimated functional connectivity states using K-means clustering, and then investigated group differences with respect to the connectivity strengths in states, the dwell time in each state, and the transition times between states. Finally, graph metrics of time-varying connectivity patterns and connectivity states were assessed. Results suggest that measured by the overall connectivity, HC showed stronger inter-subsystem interaction than patients. Compared to HC, patients spent more time in the states with nodes sparsely connected. For each state, SZ patients presented relatively weaker connectivity strengths mainly in inter-subsystem. Patients also exhibited lower values in averaged node strength, clustering coefficient, global efficiency, and local efficiency than HC. In summary, our findings indicate that SZ show impaired interaction among DMN subsystems, with a reduced central role for posterior cingulate cortex (PCC) and anterior medial prefrontal cortex (aMPFC) hubs as well as weaker interaction between dorsal medial prefrontal cortex (dMPFC) subsystem and medial temporal lobe (MTL) subsystem. For SZ, decreased integration of DMN may be associated with impaired ability in making self-other distinctions and coordinating present mental states with episodic decisions about future.

KEYWORDS:

Connectivity states; Default mode network; Dynamic functional connectivity; Schizophrenia; fMRI

PMID:
26654933
PMCID:
PMC4707124
DOI:
10.1016/j.schres.2015.11.021
[Indexed for MEDLINE]
Free PMC Article

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