Altered functional connectivity of the cingulate subregions in schizophrenia.

D Wang,C Zhuo,W Qin,Y Zhou,L Xu,J Zhu,H Liu,C Yu

doi:10.1038/tp.2015.69

Abstract

Schizophrenia patients have shown altered resting-state functional connectivity (rsFC) of the cingulate cortex; however, it is unknown whether rsFCs of the cingulate subregions are differentially affected in this disorder. We aimed to clarify the issue by comparing rsFCs of each cingulate subregion between healthy controls and schizophrenia patients. A total of 102 healthy controls and 94 schizophrenia patients underwent resting-state functional magnetic resonance imaging with a sensitivity-encoded spiral-in imaging sequence to reduce susceptibility-induced signal loss and distortion. The cingulate cortex was divided into nine subregions, including the subgenual anterior cingulate cortex (ACC), areas 24 and 32 of the pregenual ACC, areas 24 and 32 of the anterior mid-cingulate cortex (aMCC), posterior MCC (pMCC), dorsal (dPCC) and ventral (vPCC) posterior cingulate cortex (PCC) and retrosplenial cortex (RSC). The rsFCs of each cingulate subregion were compared between the two groups and the atrophy effect was considered. Results with and without global signal regression were reported. Most cingulate subregions exhibited decreased rsFCs in schizophrenia after global signal regression (GSR). Without GSR, only increased rsFC was found in schizophrenia, which primarily restricted to the aMCC, PCC and RSC. Some of these increased rsFCs were also significant after GSR. These findings suggest that GSR can greatly affect between-group differences in rsFCs and the consistently increased rsFCs may challenge the functional disconnection hypothesis of schizophrenia.

Highlights

After global signal regression (GSR), which suggests that the functional disconnection of the affective network (AN) may contribute to emotional disturbance in schizophrenia
We cannot exclude that the connectivity change may be a result of GSR
Because each cingulate subregion connects with its specific functional networks, we shall discuss our findings from the perspective of Altered connectivity of the pregenual anterior cingulate cortex (pACC) in schizophrenia

Summary

Introduction

Schizophrenia is a severe psychiatric condition characterized by hallucination, delusion and impaired perception and cognition,[1,2] which have been attributed to structural and functional alterations of the brain, including the cingulate cortex.[3,4,5] Schizophrenia patients have exhibited abnormalities in cortical thickness,[6] gray matter volume (GMV),[7] metabolism,[8] cerebral blood flow,[9] taskevoked activation,[10] spontaneous activity,[11] anatomical connection[12] and resting-state functional connectivity (rsFC) 13 in the cingulate cortex. The cingulate cortex is a structurally[14] and functionally[15] heterogeneous region. On the basis of integrated neurobiological assessments, it has been roughly subdivided into seven subregions, including the subgenual (sACC) and pregenual (pACC) parts of the anterior cingulate cortex (ACC), the anterior (aMCC) and posterior (pMCC). Parts of the mid-cingulate cortex (MCC), the dorsal (dPCC) and ventral (vPCC) parts of the posterior cingulate cortex (PCC), and the retrosplenial cortex (RSC).[16] According to cytoarchitectonic features, the pACC and aMCC can be further subdivided into two subregions, that is, the area 24 and the area 32. A total of nine subregions could be identified for each side of the cingulate cortex

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