Development and plasticity

Authors: Rémy Pujol
Contributors: Sam Irving

Whilst the human cochlea has completed its development by birth, the brain’s auditory pathways and centres develop more slowly and progressively, from the brain stem to the auditory cortex.

Table I: timing of maturation of the organ of Corti in different species

This table gives comparative timings of stages 2 (onset of hair cell morphological differentiation), stage 4 (onset of cochlear potentials), and stage 5 (end of maturation) in different mammals (see next page).

wg = weeks of gestation (humans) ; ed = embryonic days ; pnd = postnatal days

Espèces

Stade 2

Stade 4

Stade 5

Human

10 wg 18 wg  30 wg

Rat, Mouse

 16-17 ed  8-10 pnd  16-20 pnd

Cat

 ? (ed)  3 pnd  20 pnd

Guinea-Pig

 34 ed  54 ed  6 pnd

Gerbil

 ? (ed)  12 pnd

 20 pnd

Table II: comparative development of the cochlea and the auditory brain in both humans and rats

This table recalls stages 2,4, and 5 (see above) of cochlear maturation and highlights the late development of the auditory brain.

Actually, to mature properly, the brain requires the cochlea to be fully mature and functional. An early detection and rehabilitation of a peripheral (ear) impairment is thus essential !