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Abstract:
Stimulus repetition improves performance and modulates
event-related brain potentials in word recognition tasks. We
recorded cortical magnetic responses to determine the brain area
related to the word repetition effect. Subjects were 14 Japanese
volunteers (right-handed). They read visually presented words or
pronounceable nonwords, some of which occurred twice with a lag of
eight items. Recordings were taken over the bilateral temporal site
of the brain with dual gradiometers with 37 sensors (BTi Inc).
Clear magnetic responses were observed in the responses from both
hemispheres. In the left hemisphere, the range of 300-500 ms after
stimulation. The effect was not observed in the responses to the
nonwords. In the right hemisphere, the effect in the latency range
of 300-500 ms was found neither in the words nor in the nonwords.
The sources of the responses in the left hemisphere were located in
the peri-Sylvian area (mostly adjacent to the auditory area) and
the parietal area (mostly in the angular gyrus). The strength of
the peri-Sylvian source was reduced by the word repetition, whereas
it was not by the nonword repetition.
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