Latencies of the Sensory and Cognitive Components of Event-Related Potentials on Perception of Verbal Stimuli in Health and Schizophrenia

Abstract

We report here studies of the early and later stages of cerebral information processes during passive reading of concrete words in healthy subjects and patients with schizophrenia using an event-related brain potentials method. Comparative analysis of the P100, N170, P200, and P300 components in the implicit situation showed that the latencies of the early components P100 and N170 were shorter in schizophrenia patients, while the latencies of the later P200 and P300 components were longer than those in healthy subjects. This suggests that schizophrenia involves a deficit in automated sensory processing of the stimulus, apparent as a shorter latency for the sensory components of the event-related potential, with the result that sensory analysis of the stimulus was incomplete and imprecise. The negative correlations between the latencies of the P100 and P200 components (“recognition potentials”) detected here in healthy subjects supported the hypothesis that the longer-lasting sensory processing of verbal stimuli shortens the time taken for its recognition. In schizophrenia patients, the ratio of the durations of the sensory and cognitive components of the event-related potential was impaired. A positive correlation was found between measures of the early and late components of potentials, perhaps because of the presence of nonsensory elements in the structure of the early components of event-related potentials.