A study of perceptual binding in schizophrenia

Abstract

Recent neuroimaging evidence suggests that schizophrenia may involve dysfunction in cooperative activities between brain areas. One potential mechanism for coordination is the phenomenon of neural synchronisation. Cognitively, such coordination is reflected in perceptual binding. We used a contour integration test to investigate if perceptual binding dysfunction occurs in schizophrenia. Twenty-eight DSM-IV diagnosed chronic schizophrenic patients were compared with normal controls. They were requested to identify contours comprised of Gabor elements separated from one another with a constant density. The amount of misalignment in orientation was manipulated so that the more misalignment the more difficult the task. Stimuli were presented either in a completely randomised order or in increasing levels of difficulty. Patients' performances were below those of control subjects when stimuli were presented sequentially. However, in random presentation, patients' performance was similar to controls. We conclude that schizophrenic patients do not show evidence for perceptual binding impairment. In addition, they benefit less from prior exposure to the easier items compared with controls.