A.M. Guihard-Costa (guihard@CIMRS1.MNHN.FR)
Mon, 6 Feb 1995 12:36:47 -0500
I am very delighted with the current discussion on brain development. I am
working on fetal growth and development, and have recently published
several papers about brain growth (see : Early Hum. Dev., 1990; Biol.
Neonate, 1992, 62 : 309-316). I would like to contribute to Holloway's
argument concerning the relationship between brain mass and brain
functionality. I have just published a paper ("Fetal growth and human
evolution. An hypothesis of heterochrony", C.R. Acad.Sci.Paris, t.319,
s=E9rie 2 : 839-843)), in which I state the hypothesis of a possible
dissociation between the growth in size, and the maturity of brain
neonate, during human evolution. This hypothesis is not unlikely.
Biological arguments come from the study of modern fetal pathology : in
case of intrauterine growth retardation, the maturity of the brain is equal
to that of eutrophic fetuses with identical gestational age. Furthermore,
the production of pulmonary "surfactant factor" is accelerated in
intrauterine growth retardated infants. Moreover, this process of
dissociation between brain maturation and growth was the most advantageous
for the fetus, because his neurophysiological development was not retarded.
What part this process played in human evolution is still arguable. ..
A bient=F4t, j'attends vos commentaires !
Laboratoire d'Anthropologie, Mus=E9e de l'Homme, Paris