RESUMO
The present study investigates the early stages of selection of meaningful and meaningless verbal-in- formation in an implicit and two explicit tasks by means of the parameters of latency and amplitude of P100 EP component in healthy subjects (n = 99) and in schizophrenia patients with the first psy- chotic episode (n = 102). The obtained results indicate the disturbance of passive perception of meaningful verbal information in psychotic patients. When the instruction is presented patients re- spond similar to norm. The decreased amplitude of P100 component during the,passive perception of words in patients may be related to the severity of hallucinatory behavior. The analysis of changes in the characteristics of the P100 wave in task with instruction as compared to passive perception in the norm revealed a shortening of the time window'of the processing of information regardless to its category and relevance. In schizophrenia patients this feature was found only when reading of the pseudo-words. The results indicate the disturbance of automated attraction of attention to the semantically significant content of the verbal stimulus in the patients' group. The study demonstrat- ed the association between P100 wave characteristics and behavioural responses.