Neuroimaging of frontal–limbic dysfunction in schizophrenia and epilepsy-related psychosis: Toward a convergent neurobiology

Psychosis is a devastating, prevalent condition considered to involve dysfunction of frontal and medial temporal limbic brain regions as key nodes in distributed brain networks involved in emotional regulation. The psychoses of epilepsy represent an important, though understudied, model relevant to understanding the pathophysiology of psychosis in general. In this review, we (1) discuss the classification of epilepsy-related psychoses and relevant neuroimaging and other studies; (2) review structural and functional neuroimaging studies of schizophrenia focusing on evidence of frontal–limbic dysfunction; (3) report our laboratory's PET, fMRI, and electrophysiological findings; (4) describe a theoretical framework in which frontal hypoactivity and intermittent medial temporal hyperactivity play a critical role in the etiopathology of psychosis both associated and unassociated with epilepsy; and (5) suggest avenues for future research.

► Frontal–limbic brain networks mediate emotion regulation.
► Schizophrenia and psychoses of epilepsy likely share frontal–limbic neurocircuitry defects.
► Studying both can provide an integrated systems-level model of psychosis.
► This may have implications for treatment.