Cognitive subprocesses and schizophrenia. B. Maze tasks

In a companion paper we demonstrated that in reaction-time tasks the response selection stage is selectively disturbed in schizophrenia. The aim of the present study is the investigation of subprocesses, which are incorporated into repeatedly activated loops of cognitive processes and need additional information from working memory.

Maze tasks of varying complexity (with and without bifurcations) were presented to drug-naive and treated first-onset schizophrenic patients. The tasks had to be solved under easy and difficult motor-conditions. Both patient samples were compared with healthy control groups matched by age, sex, education and experience with the experimental setting.

In mazes with alternative routes patients exhibited the expected decrease of performance. However, untreated patients improved under difficult motor conditions. This improvement is smaller after neuroleptic treatment.

Under difficult motor conditions attention is focused on the execution of movements and thus withdrawn from perceiving irrelevant response alternatives, i.e. the effects of disturbed response selection are reduced.