Impaired modulation of the saccadic contingent negative variation preceding antisaccades in schizophrenia

Background: The contingent negative variation (CNV) is considered to reflec t prefrontal functioning and can be observed before manual and ocular motor responses. Schizophrenic patients exhibit reduced CNV amplitudes in tasks requiring manual motor responses. A number of studies has also found normal prosaccades, but delayed antisaccades and an augmented rate of erroneous p rosaccades during the antisaccade task in schizophrenia. In this study we e xamined the CNV during pro- and antisaccade tasks in schizophrenic patients and healthy control subjects. Methods: Data of 17 medicated schizophrenics (IICD-10, F20) and 18 control subjects, matched with patients for age, gender, and education were analyze d. Horizontal pro- and antisaccades were elicited in four blocks, each cons isting of 80 trials. Electroencephalogram was recorded from 32 channels wit h a DC amplifier. Results: Patients exhibited delayed correct responses and more erroneous pr osaccades during the antisaccade task than control subjects, but normal pro saccadic reaction times. In control subjects, the vertex-predominant saccad ic CNV was generally larger than in patients, and larger during the anti- t han during the prosaccade task. This task-related amplitude augmentation wa s absent in patients. Analyses of additional components suggested specifici ty of impaired event-related potential modulation to the saccadic CNV. Conclusions: In accordance with the presumed prefrontal dysfunction, our re sults suggest deficient preparation and execution of antisaccades in schizo phrenia. (C) Society of Biological Psychiatry.