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Abstract:
It is well known that late cognitive components of the ERP
show prolonged developmental changes. Recently, we demonstrated
that the N1, an early component, also underwent extensive
developmental changes when evoked by speech consonants. Considering
the simplicity of a speech consonant, this finding was surprising
and raised the question of whether the N1 to an even simpler
stimulus, a tone, would show comparable maturational changes.
We examined 70 children (3-16yrs, grouped in 2yr intervals) and 10
adults. Tones were 2KHz, 36ms, 77dB with a 600ms ISI. We recorded
from 26 electrodes and re-calculated an average reference.
As expected, the children showed a prominent N1c at the
midtemporal sites. However, considerable age-related changes were
observed in the N1 along the midline chain and the posterior
temporal electrodes. At both Fz and Cz, the N1b increased in
amplitude and decreased in latency with age, whereas at posterior
temporal sites, the N1a decreased in both amplitude and latency
with age. The developmental pattern between speech and tonal
stimuli was comparable although the response to tonal stimuli seems
to mature earlier.
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