Antisaccade performance of schizophrenia patients: evidence of reduced task-set activation and impaired error detection.

The antisaccade task is well suited to study the interplay between environmental stimuli and action goals in controlling behavior. It requires subjects to look to the mirror position of visual stimuli. Schizophrenia patients usually show enhanced rates of erroneous saccades toward the stimulus. The present study was designed to investigate the role of task set activation and error detection for this impairment. Fifteen patients with a diagnosis of schizophrenia and 15 control subjects made antisaccades under standard conditions and under precue conditions. In the precue conditions the imperative visual stimulus was immediately preceded by short precues on either the same or the opposite side. Subjects had to evaluate their performance on each trial. Schizophrenia patients showed enhanced error rates on the standard condition and after same side precues but not after opposite side precues. Opposite side precues entailed increased errors in both groups, but the increase was weaker in schizophrenia patients. This lower precue effect in schizophrenia is proposed to reflect reduced activation of the task set for antisaccades in schizophrenia. The study also revealed strongly impaired error detection in schizophrenia. The relative roles of task-set activation and error detection for poor antisaccade performance in schizophrenia are discussed.