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Quantitative analysis of somatosensory cortex development in eutherians, with a comparison with metatherians and monotremes.

Authors :
Ashwell KW
Source :
Somatosensory & motor research [Somatosens Mot Res] 2015; Vol. 32 (3), pp. 137-52. Date of Electronic Publication: 2015 Apr 17.
Publication Year :
2015

Abstract

Extant eutherians exhibit a wide range of adult brain sizes and degree of cortical gyrification. Quantitative analysis of parietal isocortical sections held in museum collections was used to compare the pace of somatosensory cortex development relative to body size and pallial thickness among diverse eutherian embryos, foetuses, and neonates. Analysis indicated that, for most eutherians, cortical plate aggregation begins at about 6-18 mm greatest length or about 120-320 µm pallial thickness. Expansion of the proliferative compartment occurs at a similar pace in most eutherians, but exceptionally rapidly in hominoids. Involution of the pallial proliferative zones occurs over a wide range of body sizes (42 mm to over 500 mm greatest length) or when the cerebral cortex reaches a thickness of 1.2-9.8 mm depending on the eutherian group. Many of these values overlap with those for metatherians. The findings suggest that there is less evolutionary flexibility in the timing of cortical plate aggregation than in the rate of expansion of the pallial proliferative compartment and the duration of proliferative zone activity.

Details

Language :
English
ISSN :
1369-1651
Volume :
32
Issue :
3
Database :
MEDLINE
Journal :
Somatosensory & motor research
Publication Type :
Academic Journal
Accession number :
25884290
Full Text :
https://doi.org/10.3109/08990220.2015.1004046