Early and late components of visual categorization: an event-related potential study

We examined the characteristics of early and late components of event-relat ed potentials (ERPs) accompanying the visual categorization of natural scen es. In the first experiment, ERPs were recorded in an animal-non-animal cat egorization task (CT), whereas the second experiment included a spatial fre quency discrimination task (DT). In the CT, there were more negative potent ials for non-animals in the time windows of 150-250 ms (N1) and 350-500 ms (N2), and a more positive potential for animals in the time window of 250-3 50 ms (P2). In the DT, spatial frequency gratings evoked only a short-durat ion difference N1 at the frontal sites. Our results suggest that N1 may be related to higher-level categorization processes. (C) 2000 Elsevier Science B.V. All rights reserved.