The embodied self in psychosis: Relationships among insula functional connectivity and emotional embodiment in schizophrenia-spectrum disorders

Disturbances in the self are central to schizophrenia-spectrum disorders (SZ) and may arise from abnormalities in emotional embodiment, or the representation of emotions through bodily sensations. The insular cortex plays a central role in interoception and emotional awareness, yet the relationship between emotional embodiment and insular functional connectivity (FC) remains unclear. We tested whether reduced differentiation of bodily emotion representations is associated with reduced differentiation of insular subregional FC profiles in SZ.

Resting-state fMRI and emotional embodiment data were analyzed in 31 SZ and 40 healthy comparison (HC) participants. Emotional embodiment was assessed using the EMBODY task, in which participants mapped bodily sensation associated with a range of emotions. Seed-to-voxel FC analyses were performed for posterior, dorsal anterior, and ventral anterior insular subregions, and differentiation of their FC profiles was quantified using η².

SZ participants exhibited significantly less differentiated bodily representations of emotions than HC participants. Insular subregional differentiation was statistically similar between groups, although SZ participants demonstrated reduced FC between the posterior insula and primary motor cortex and between the dorsal anterior insula and Broca's area. Lower differentiation of posterior and dorsal anterior insular FC profiles was associated with lower embodied activation for anger and depression.

Schizophrenia is characterized by less differentiated bodily representations of emotion, but these alterations showed only limited associations with insular subregional FC differentiation. These findings suggest that altered emotional embodiment in schizophrenia cannot be explained solely by reduced differentiation of insular functional connectivity and motivate further investigation using task-based neuroimaging paradigms.