Schizophrenia and the Neglect Syndrome: Parietal Contributions to Cognitive Dysfunction in Schizophrenia

Many of the positive symptoms of schizophrenia, including hallucinations and passivity phenomena, have been related to dysfunction within association cortices. In addition, many of the cognitive deficits observed in patients with schizophrenia can also be characterised as impairments of higher level cognitions known to depend on these same association cortices. While most attention has been directed towards dysfunction of the frontal and temporal cortices, there is mounting evidence for impaired functioning of the parietal cortices as well. That is, there is a substantial body of research demonstrating impaired spatial and motor behaviours in patients with schizophrenia - behaviours known to depend on the parietal cortex. In this selective review we contrast some of these impairments with a neurological syndrome that commonly arises from damage to the right parietal cortex, known as unilateral neglect. Although the spatial impairments characteristic of neglect are far more severe than those observed in patients with schizophrenia, there are some important parallels that make the comparison worthwhile. We intend to outline those parallels and highlight ways in which they may inform models of schizophrenia.