Structural connectivity of an interoception network in schizophrenia

Interoception refers to the processing, integration, and interpretation of bodily signals by the brain. Interoception is key to not only basic survival, but also many cognitive processes, especially motivational and affective functioning. There is emerging evidence suggesting altered interoception in schizophrenia, but few studies have explored their potential neural underpinning. The current study aims to investigate the anatomical connectivity of a previously identified interoception network in individuals with schizophrenia, and the relationship between structural connectivity in this network and both emotional functioning and clinical symptoms. Thirty-five participants with schizophrenia (SZ) and 36 healthy control participants (HC) underwent diffusion tensor imaging (DTI) and performed tasks measuring emotional functioning. Probabilistic tractography was used to identify white matter tracts connecting key hubs in an interoception network (rostral and caudal anterior cingulate cortex, ventral anterior insula, dorsal mid and posterior insula, and amygdala). Microstructural integrity of these tracts was compared across groups and correlated with measures of emotional functioning and symptom severity. Compared with HC, SZ exhibited altered structural connectivity in the interoception network, specifically between the amygdala and the insular cortex. In HC, the structural connectivity of the network was significantly correlated with emotion recognition, supporting a link between the interoception network and emotional functioning. However, this correlation was much weaker in SZ, suggesting less involvement of this network. These findings suggest that altered interoception may have implications for illness mechanisms of schizophrenia, especially in relation to emotional deficits.