The possible importance of the inferior colliculi
for language development is based on four
major considerations:
Maturation of the cerebral cortex continues after birth guided by
trophic neurotransmitters produced in neurons of brainstem nuclei
[96-98].
1.
The brainstem
auditory pathway
is fully myelinated
and functional in
the human fetus
by 29 gestational
weeks [97, 98].
2.
Myelin in the
human brainstem
auditory pathway
at 25 gestational
weeks (sagittal
view).
Myelin in the
human brainstem
auditory pathway
at 29 gestational
weeks (horizontal
view).
Myelination of the later maturing target areas for the
brainstem auditory pathway (the temporal and frontal
language areas of the cortex) continues over the first four
years of post-natal life.
3.
Thus children normally learn to speak “by ear” before the
language areas of the cortex are fully developed.
4.
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October 2006
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