Electrophysiological evidence of a semantic system commonly accessed by animals and tools categories

Some theoretical perspectives propose a semantic system in which categories are represented in different brain regions. Others assume that distinction s are based rather on differences in the demands placed by different catego ries on shared processing systems. In this study semantic categorization pr ocesses were investigated using the recognition potential (RP), an event-re lated brain response that reflects semantic processing, peaks at around 250 ms after stimulus onset and originates in areas subserving perceptual-sema ntic analyses. Results indicate that the RP shows some degree of sensitivit y to categorization processes, but that categories assumed to differ marked ly in their processing demands share, to a large extent, a common neural ge nerator. This provides support for the non-categorical view on the organiza tion of the semantic system, though introducing subtle variations, and sugg esting the existence of a semantic subsystem specializing in the processing of perceptual-semantic features regardless of the semantic category involv ed. (C) 2001 Elsevier Science BY. All rights reserved.