Simultaneously decreased temporal variability and enhanced variability-strength coupling of emotional network connectivities are related to positive symptoms in patients with schizophrenia.

Abstract

We hypothesize that decreased temporal variability of emotional network connectivities, corresponding to a continual state of hyperactivity, may play a role in mediating symptoms in schizophrenia. Resting-state magnetic resonance data were collected from 64 subjects, including 21 positive symptom profile schizophrenia patients (PSZ group), 19 negative symptom profile schizophrenia patients (NSZ group), and 24 healthy controls. The emotional brain network was defined based on the coordinates obtained from multi-level kernel density analysis. The temporal variability of intra-network functional connectivities (FCs) was calculated by constructing networks from blood oxygen level-dependent signals at successive, non-overlapping time windows, and was compared between groups. The results showed that the mean FC-variability of the whole emotional network (P = 0.021), and the FC-variabilities in the bilateral anterior insula (both, P < 0.001) were significantly decreased in the PSZ group compared with the control and NSZ groups. Abnormally enhanced negative coupling between variability and FC strength (V-S coupling) was observed in the PSZ group (P = 0.027). In summary, this study found a relation between the positive symptoms of schizophrenia and decreased variability of emotional network connectivities. These findings may help us better understand the neurobiological effect of the time-varying properties of the brain network in schizophrenia patients, and the underlying relation to the generation of psychosis.