Manipulation of Event-Related Potential Manifestations of Information Processing Stages

Abstract

The timing of two event-related potential components was differentially affected by two experimental variables. The earlier component (NA) was affected by degradation of the stimuli and the later component (N2) by the nature of a classification task. The results support the hypothesis that NA and N2 reflect sequential stages of information processing, namely, pattern recognition and stimulus classification.

Event-Related Potential Components Analysis of Cognitive Impairment in Patients with Multiple Lacunar Infarcts.

“…In addition, the delay of visual N2 was not due to a delay of the preceding NA, although NAis known to occur in the latency range of the N2 peak of the ERP (8,9). NAand N2 reflect sequential stages of information processing, namely, pattern recognition and stimulus classification (8). The peak latency of N2 varies as a function of the difficulty of discrimination, and precedes and correlates with the timing of discriminative behavioral responses (9).…”

“…The present study showed that the visual N2 latency was delayed in patients with multiple lacunar infarcts. In addition, the delay of visual N2 was not due to a delay of the preceding NA, although NAis known to occur in the latency range of the N2 peak of the ERP (8,9). NAand N2 reflect sequential stages of information processing, namely, pattern recognition and stimulus classification (8).…”

“…One possible explanation for the lack of an inter-group difference in P3 may be that different strategies were used for the patients and the normal subjects. P3 reflects aspects of cognitive information processing that follow the decision that an unexpected though significant event (stimulus) has occurred (8). According to the 'context updating' hypothesis (18), the postdecision process is involved in an updating of current representations in working memory.…”

“…Figure 1 shows an example of the ERPwave forms in a normal subject. NAand N2 were elicited according to the method reported by Ritter et al (8,9). To more clearly delineate N2, the ERPs to the frequent stimuli were subtracted from those to the infrequent stimuli for each subject in each discrimination tasks.…”

“…However, there are few detailed analyses of the N2 component. Ritter et al (8,9) demonstrated that the timing of two event-related potential (ERP) components was differentially affected by two experimental variables. The earlier component (NA) was affected by degradation of the stimuli and the later component (N2) by the nature of a classification task.…”