Evidence for Dysfunction of Parietal Association Areas in Patients with Schizophrenia Characterised by Passivity Delusions.

Abstract:
In patients with schizophrenia passivity delusions are characterised by a difficulty in determining the agency of purposive actions. Neuropsychological and functional neuroimaging data suggest that passivity delusions are associated with dysfunction of parietal lobe association cortex. We compared the ability to generate motor and visual imagery, the abilty to make saccades on the basis of forward models of efference copy and volume of grey matter in the parietal lobe between 12 patients with schizophrenia characterised by somatic passivity delusions was compared statistically and 12 patients without passivity delusions. Compared to patients without passivity delusions, the patients with somatic passivity showed impaired motor imagery, normal visual imagery, impaired saccadic function and reduced cortical volume in the parietal and frontal association cortices. These data provide direct evidence for the involvement of the parietal lobe in the pathophysiology of schizophrenia.