Schizophrenia patients show eye movement abnormalities that suggest dysfunction in neocortical control of the oculomotor system. Fifteen never-medicated, first episode schizophrenia patients and 24 matched healthy individuals performed eye movement tasks during functional magnetic resonance imaging studies. For both visually guided saccade and smooth pursuit paradigms, schizophrenia patients demonstrated reduced activation in sensorimotor areas supporting eye movement control, including the frontal eye fields, supplementary eye fields, and parietal and cingulate cortex. The same findings were observed for an oculomotor delayed response paradigm used to assess spatial working memory, during which schizophrenia patients also had reduced activity in dorsolateral prefrontal cortex. In contrast, only minimal group differences in activation were found during a manual motor task. These results suggest a system-level dysfunction of cortical sensorimotor regions supporting oculomotor function, as well as in areas of dorsolateral prefrontal cortex that support spatial working memory. These findings indicate that a generalized rather than localized pattern of neocortical dysfunction is present early in the course of schizophrenia and is related to deficits in the sensorimotor and cognitive control of eye movement activity.
Bibliographical noteFunding Information:
This publication was supported by funds received from NIH grants MH62134, MH45156 and MH01433, the NIH/NCRR/GCRC grant #M01 RR00056, and a grant from the National Alliance for Research on Schizophrenia and Depression. We thank Drs. Cameron S. Carter, Gretchen Haas, and Debra Montrose and the clinical core staff of the Center for the Neuroscience of Mental Disorders (MH45156) for their assistance in clinical assessments.
- Cingulate cortex
- Dorsolateral prefrontal cortex
- Frontal eye fields
- Intraparietal sulcus
- Spatial working memory