Morphometric study on the postnatal growth of non-cortical brain regions in Australian aborigines and Caucasians.

In an autopsy study on 29 male and 27 female Aborigines and 57 male and 37 female Caucasians the volumes of a large number of brain regions were determined and fitted to logistic growth functions. For Aboriginal adults significantly smaller values were found for weight and volume of the whole brain, cerebrum, and cerebellum and for the volumes of cerebral white matter, thalamus, amygdaloid body (females only), and globus pallidus (males only). No significant differences were found for caudate nucleus, putamen, amygdaloid body (males only), and globus pallidus (females only). Almost every region studied showed later half-value times, slower growth rates, and prolonged growth phases for Aborigines compared to Caucasians. These results are discussed in relation to secular changes of growth parameters of the human brain during the last century, timing of growth phases for each area, and the socioeconomical and health status of Aborigines.