Gamma-band network segregation links corollary discharge dysfunction and anomalous self-experiences in schizophrenia

Anomalous self-experiences (ASEs) are a core feature of psychotic disorders and reflect disturbances in ipseity. Impairments in corollary discharge mechanism have been proposed as a neurobiological substrate of ASEs, and an imbalance between brain network integration and segregation, may impair the coherent flow of mental contents, thereby disrupting their fluid and implicit character. However, the relationship between corollary discharge and functional network properties has not been directly examined. This link was assessed in thirty participants with schizophrenia and thirty healthy controls. Functional network was computed using the Phase Locking Value (PLV) from resting-state EEG in the gamma band and two parameters were calculated: the clustering coefficient (ClC, as a proxy for segregation) and the path length (PL, as a proxy for integration); corollary discharge was indexed by N1 suppression in a talk-listen paradigm; and ASEs were evaluated using the 'Inventory of Psychotic-Like Anomalous Self-Experiences' (IPASE) total score. Patients with schizophrenia showed significantly greater gamma-band network segregation and lower integration than healthy controls. Moreover, higher segregation in this band was associated with reduced N1 suppression and greater ASEs severity in patients, whereas network integration was not associated with N1 suppression nor ASEs. These findings suggest that excessive gamma-band network segregation may be correlated with disrupted corollary discharge functioning and may compromise the distinction between self-generated and external stimuli. Therefore, it may alter the sense of ipseity by interfering with the integration of mental contents into the flow of consciousness, thereby contributing to greater severity of ASEs.