Increased semantic and repetition priming in schizophrenic patients

Positive and negative priming (PP and NP) in schizophrenia were studied with a lexical-decision task. Probe words, presented 800 ms after the response to the prime (containing a word and a nonword), were either identical to, semantically related to, or unrelated to the prime target word (PP) or to the prime distractor word (NP). Schizophrenic patients displayed stronger semantic and repetition PP than controls after controlling for their slower responses. Significant NP was observed in both groups for word repetition only. The PP findings contrast with results from studies with similar prime-probe intervals but without prime responses. It is proposed that schizophrenic patients, because of impaired (controlled) processes of response selection, strongly benefit from (or rely on) the automatic retrieval of processing episodes containing response information. Related findings indicating automatic response facilitation in schizophrenia are discussed.     

BIOFEEDBACK OF EVENT-RELATED SLOW POTENTIALS OF THE BRAIN

A biofeedback paradigm was developed for self-regulation of cortical DC-shifts. Subjects received continuous visual feedback of their actual DC-shift during six sec. intervals. Feedback trial series alternated with transfer test trial series. Several studies demonstrated that subjects are able to achieve cortical self-regulation which is maintained and even improved in transfer test trials. This method is used to investigate the covariation of DC-shifts and performance in reaction time tasks, mental tasks and signal detection by varying DC-shifts systematically. The procedure was also applied to different patient groups to test the functional significance of distinct brain regions and to explore deficits in patient groups.