Cerebellar-thalamic connectivity in schizophrenia.

Abstract

The literature on alterations in brain structure and function in schizophrenia, particularly in relationship to impairments in cognitive, motor, and affective functions, has made it increasingly clear that changes in the function of a single brain region cannot explain the range of impairments seen in this illness.1–4 This realization has led to a surgence of interest in studies examining neurobiological changes in schizophrenia from the perspective of brain networks and connections among brain regions and networks, with a particular focus on neural circuits known to work together to support sensory, cognitive, and emotional processes.5 This shift in focus is consistent with long-standing hypotheses about schizophrenia as a “dysconnection” syndrome, where impairments in cognition and behavior occur because of a failure of coordinated action across multiple brain regions. As many researchers have noted,6 versions of this hypothesis were put forth as early as the work of Wernicke7 and Bleuler.8 Further, theories about abnormalities in connections among brain regions have also played a central role in more recent theories of the pathophysiology of schizophrenia. For example, one such prominent theory, put forth by Andreasen and colleagues,9 suggested that schizophrenia involves a disruption in the integration of cortical-subcortical-cerebellar circuits, a hypothesis termed “cognitive dysmetria.”