| |
Abstract:
Abstract: We investigated the influence of lexical and
semantic factors on word-evoked MEG responses. There were four
stimulus groups, function words, action verbs, and two groups of
nouns, one primarily eliciting visual associations the other
associations related to both the visual and action modality. Thus,
there were three lexical categories (function, verb, noun), and we
classified word into three semantic groups, depending on the number
of modalities relevant for word meaning (amodal, unimodal,
multimodal). All stimulus groups were carefully matched for word
length and frequency. Already 100 ms after onset of visual stimuli,
the noun group with multimodal associations evoked stronger
neuromagnetic fields compared to all other word categories.
Subsequent to this early difference, MEG responses to words from
the different lexical categories diverged. These findings are
important for both language and brain theories. Word meaning
appears to become relevant for neuromagnetic activity at an
unexpectedly early point in time, and even before MEG traces of the
lexical categories separate. Activity spreading in distributed
cortical networks can influence brain responses already shortly
after activity reaches the cortex. The most widely distributed
networks and, correspondingly, the words whose semantic
associations involve the largest number of modalities, produce the
most pronounced brain response around 100-150 ms.
|
