Event-related brain potentials evoked by verbs and nouns in a primed lexical decision task

We investigated whether verbs and nouns evoke comparable behavioral and N40 0 effects in a primed lexical decision task. Twenty-nine students were test ed, 13 in a pilot study in which only response times and error rates were c ollected and 16 in a study in which ERPs were recorded from 124 scalp elect rodes. Stimuli were noun-noun and verb-verb pairs with the targets bearing either a strong, a moderate, or no semantic association to the prime or bei ng a pseudoword. Behavioral data revealed comparable priming effects for bo th word categories. These proved to be independent from the SOA (250 and 80 0 ms) and they followed the well-known pattern of decreasing response times and error rates with increasing relatedness between target and prime. ERPs revealed pronounced N400 effects for both word categories with a larger am plitude for noun than for verb pairs. A systematic analysis of topographic differences between noun- and verb-evoked ERPs and N400 effects, respective ly, gave no convincing support to the hypothesis that the two word categori es activate distinct neuronal networks.