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Abstract:
Abstract: In a dense-array EEG study where subjects had to
make a difficult self-evaluative decision about trait-descriptive
words, previous stimulus-locked analyses revealed a specific
sequence of neuroelectric events leading up to the response. At 350
ms post stimulus, an interaction effect between word valence
(good/bad trait) and endorsement (yes/no response) was seen over
centromedial frontal cortex. By 450 ms, a highly significant
discrimination was seen over the frontal poles, with greater
negativity for "no" responses and positivity for "yes" responses,
regardless of whether the word described a good or a bad trait.
However, because these events were locked to stimulus onset,
detailed temporal information with respect to the actual response
needs clarification. In this study, we clarify these events and
their temporal relation to the actual response. We were able to
replicate the primary findings, and coupled with the
stimulus-locked findings, we gained greater insight into the
processes that occur between seeing a trait descriptive word and
responding to whether it is an accurate self-description. Given the
connectivity of frontal networks, the temporal sequence of these
electrical effects suggests that the decision first organizes both
motivational and semantic features within the anterior cingulate
gyrus and associated centromedial frontal cortex. The intention to
respond then takes form within more anterior networks of prefrontal
cortex.
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