Cognitive mechanisms of sensorimotor dysfunction in schizophrenia

The research is aimed at studying the cognitive mechanisms of sensorimotor dysfunction in schizophrenia. 26 patients with schizophrenia and 26 healthy subjects performed the monitoring task of the Multi-Attribute Task Battery (MATB). Participants had to distribute attention between several sources of information and respond to appearing visual signals. Indicators of task performance and parameters of eye movements, heart rate and pupil diameter were recorded during the research. The results of the study showed that patients with schizophrenia demonstrate significantly lower indicators of monitoring task performance than healthy subjects. Low success of task performance in schizophrenia is associated with excessive and ineffective eye movements. Compared with healthy participants, patients with schizophrenia make more high-amplitude saccades and more often look at visual signals, detection of which doesn’t require a focal attention. There was concluded that excessive eye movements in schizophrenia are determined by a deficit of voluntary oculomotor activity. The study also showed that healthy subjects exhibit an abrupt increase of indicators of physiological arousal such as heart rate and pupil diameter during a primary period of performance. This finding reflects a mobilization of cognitive resources and formation of preparatory set for a coming activity. In contrast, patients with schizophrenia demonstrate a low increase of indicators of arousal, which evidences difficulties in resource mobilization and formation of preparatory set during a primary period of performance. Thus, a degree of increase of heart rate and pupil diameter indicators during a primary period of performance is significantly associated with the characteristics of oculomotor activity and efficiency of the monitoring task performance overall. The results are explained from the standpoint of the previously developed theory of cognitive regulation.