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Abstract:
Mismatch negativity (MMN) is considered to be an automatic
discriminative response since it can be elicited while a subject's
attention is directed elsewhere (e.g., reading a book). Recently,
however, studies have shown that attention can modulate MMN
amplitude (e.g., Woldorff et al., 1991; Szymanski et al., 1999). A
study with children has reported an enhancement of MMN to tones
with active discrimination (Gomes et al., 2000). The purpose of the
present study was to further assess the effect of attention on MMN
in school-age children and adults. MMN was recorded to vowel sounds
(/I/-/e/) in passive vs. attend test conditions. In the attend
condition, subjects were asked to detect an infrequently presented
target tone among the deviant and standard vowel sounds. Behavioral
data (i.e., identification and discrimination) were also collected.
In general, behavioral findings were similar across age groups,
with the exception that reaction times were slower for the
children. MMN amplitude increased more for the children than the
adults in the attend condition compared to the passive condition.
The greatest increases in amplitude for the children were observed
over the right hemisphere. These data suggest that under certain
test conditions, the processes indexed by MMN continue to mature
during the school-age years, even though behaviorally the children
and adults show similar performance levels.
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