Prefrontal and Cerebellar Abnormalities in Major Depression: Evidence from Oculomotor Studies

Background: Neurobehavioral studies have identified multiple cognitive and motor system disturbances in depressed patients. Neuroimaging studies have identified abnormalities in neocortex, striatum, and cerebellar vermis that are probable causes of these impairments. Methods: To further clarify the origins of motor and cognitive disturbances in major depression, unmedicated depressed inpatients (n = 29) and an age- and gender-matched healthy comparison group (n = 19) were tested with a battery of oculomotor tasks selected to assess the functional integrity of frontostriatal circuitry and the cerebellar vermis. Results: Depressed patients demonstrated increased rates of response suppression errors on an antisaccade task, less accurate memory for spatial location information in a spatial delayed response task, dysmetric visually guided saccades, and increased rates of saccadic intrusions during visual fixation. Conclusions: These results provide quantitative documentation of significant disturbances in neurophysiological processes subserved by prefrontal cortex and the cerebellar vermis during episodes of major depression.