Anticipating incoming events: an impaired cognitive process in schizophrenia

Intentions are central to guiding actions to their completion because they generate expectations which precede the realization of a task. This ability to manage time was investigated by using a cognitive task which involves s everal highly integrated processes: sequential learning explicit processing , and working memory. In this task, participants are required to explicitly learn a repeating color sequence before receiving an instruction to give a n anticipatory motor response concerning the next element. Two types of seq uences (temporal and spatial) and three experimental conditions were tested in both a group of normal participants and a group of schizophrenic patien ts. Schizophrenics were included because their condition is known to alter conscious executive function. Our results showed that schizophrenic patient s have a strong deficit in performing anticipation tasks. Although they lea rned the sequences almost normally, their anticipatory ability was reduced in comparison to normal participants in all the tested conditions. These re sults expand the notion of a working memory deficit in schizophrenia and be ar strong implications for understanding executive disorders observed in su ch patients. (C) 2001 Elsevier Science B.V. All rights reserved.