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Abstract:
Abstract: The N400 has been well documented to reflect
semantic processing. This wave, when elicited by words, typically
peaks at about 400 msec after stimulus onset. The present study
predicted that if the range of possible target-words is restricted,
then the early stages of word processing (e.g. visual feature
analysis) should be completed faster, and therefore semantic
processing would occur earlier, leading to an earlier peak of the
N400. ERPs were recorded to two target words (tool and animal) that
were presented repetitively and were preceded either by
semantically matching or mismatching words. The results showed that
targets following the mismatching primes elicited larger
negative-going component that peaked at about 325msec post-stimulus
onset than the matching targets. Importantly, this N325 was
obtained in a paradigm closely similar to the semantic priming
paradigm traditionally used to elicit N400s. Moreover, this early
component was sensitive to a semantic manipulation. These results
suggest that the observed N325 is likely to be a member of the
N400-component family, therefore supporting our hypothesis that
under certain conditions processing of word meaning may occur
unusually early.
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