Convergent and divergent altered patterns of default mode network in deficit and non-deficit schizophrenia

Previous studies suggested likely mechanisms underlying the dysfunction of the default mode network (DMN) in schizophrenia. However, altered patterns of the intrinsic activity of the DMN in both deficit schizophrenia (DS) and non-deficit schizophrenia (NDS) patients, as well as the neurocognitive relationships among them, remain unknown. This study explores the resting-state characteristics of the DMN activity in both DS and NDS patients, and further investigates correlations with neurocognitive features.

Demographic, resting-state functional MRI, and neurocognitive data were collected in 37 DS and 38 NDS patients, as well as in 38 matched healthy control subjects (HCs). Independent component analysis was conducted to investigate the characteristics of DMN activity and to further distinguish between common and specific altered regions. In addition, partial correlation analysis was conducted to examine associations between the activity of altered regions and neurocognitive assessments.

Overlapping altered brain activity was observed in both DS and NDS patients in the left middle frontal gyrus (MFG), the left angular gyrus (ANG), and the calcarine sulcus (CAL) region. Furthermore, compared to HCs, DS patients showed less activity in the right inferior temporal gyrus, the right para-hippocampal gyrus / hippocampus (PHP / HIP), and the left precuneus (PCUN), while they showed increased activity in the posterior cingulate cortex (PCC). Notably, NDS patients showed less activity in the bilateral middle occipital gyrus. Correlation analysis indicated that, in the DS group, both Trail Making Test (TMT)-B and spatial processing scores were positively associated with the activities of the left PCUN and the right PHP / HIP, while the Stroop color scores were negatively associated with PCC activity. In the NDS group, the TMT-B scores were associated with activities of the left MFG and CAL regions, while the scores of the Wechsler adult intelligence scale (Chinese revision) were negatively associated with CAL region activity.

The present study demonstrates convergent and divergent altered patterns of the DMN in both DS and NDS patients. Importantly, the specific altered regions of the DMN in DS patients may be associated with extensive deficient neurocognition, indicating novel insights into the pathogenesis of cognitive impairment in schizophrenia.