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Abstract:
We report an event-related fMRI study of cerebral activity in
sixteen healthy participants during the reading of sentences that
end with a word that was either a congruent or incongruent with the
previous sentence context. This task is similar to that used to
elicit the N400 scalp electrical potential. Processing of both
congruent and incongruent sentence endings was associated with
activation in bilateral inferior frontal gyrus, cingulate gyrus,
insula, superior, middle, and inferior temporal gyri, thalamus,
fusiform gyrus and left inferior parietal lobule. The amygdala
showed significant activation during the processing of incongruent
words but only a trend towards activation for processing congruent
words. A direct comparison of the activation for incongruent words
versus that for congruent words revealed significantly greater
activation for incongruent words than congruent words in the left
lateral frontal cortex and a trend for greater activation
bilaterally in the anterior temporal lobes. These results are
consistent with data from intracranial electrical recording studies
of the N400. The results are discussed as they relate to the
localization of the cerebral sites underlying semantic
processing.
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