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Abstract:
Words (primes) presented briefly before a target facilitate
the subsequent lexical decision task (word or pseudoword) if they
are semantically related to the target words. This phenomenon is
known as semantic priming. A semantic priming effect can also be
observed electrophysiologically. However, the neural network
subserving semanting priming is not yet fully known. We conducted
an event-related fMRI with six healthy male subjects performing a
lexical decision task with short stimulus onset asynchrony (200 ms)
between prime and target. Semantic distance between prime and
target was graded. Subjects showed a typical semantic priming
effect behaviorally as measured by reaction times (non-related >
indirectly related > directly related). A fMRI semantic priming
effect was found bilaterally in the temporo-parietal cortex. In
these regions non-related words elicted a stronger BOLD-signal than
indirectly related words and indirectly related words elicited a
stronger signal than directly related words. Our study provides the
first fMRI evidence that regions known to be involved in semantic
processing contribute to the behavioral semantic priming effect in
a graded fashion.
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