Reciprocal evolution of the cerebellum and neocortex in fossil humans.
Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and Cro-Magnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.
Weaver
Anne H
AH
Department of Arts and Sciences, Santa Fe Community College, 6401 Richards Avenue, Santa Fe, NM 87508, USA. aweaver@sfccnm.edu
D005075:Biological Evolution; D002531:Cerebellum / Q000502:physiology*; D003071:Cognition; D005580:Fossils; D006801:Humans; D019579:Neocortex / Q000502:physiology*
Neuropsychologia. 1995 Apr;33(4):407-19
7617152
Nature. 1997 May 8;387(6629):173-6
9144286
Neuroimage. 1998 May;7(4 Pt 1):368-76
9626676
Z Anat Entwicklungsgesch. 1974 Jul 5;144(1):61-73
4851103
Am J Phys Anthropol. 2000;Suppl 31:61-115
11123838
J Hum Evol. 2000 Feb;38(2):317-32
10656781
Curr Anthropol. 2000 Aug-Oct;41(4):569-607
11624671
Ergeb Anat Entwicklungsgesch. 1970;43(4):3-70
4928801
Brain Behav Evol. 1981;18(1-2):60-71
7237105
Am J Phys Anthropol. 1994 Jan;93(1):1-34
8141238
Nature. 1997 Jan 23;385(6614):333-6
9002516
Nature. 2003 Mar 27;422(6930):395
12660770
Nature. 2000 Jun 29;405(6790):1055-8
10890446
Nature. 2000 Jan 13;403(6766):192-5
10646603
J Hum Evol. 2003 Apr;44(4):401-29
12727461
Prog Neurobiol. 1998 Oct;56(2):191-210
9760701
Trends Neurosci. 1993 Nov;16(11):448-50; discussion 453-4
7507615
Cereb Cortex. 2003 Sep;13(9):943-9
12902393
Brain Behav Evol. 1998;52(6):308-14
9807015
Learn Mem. 2002 Nov-Dec;9(6):376-86
12464697
Proc Natl Acad Sci U S A. 2003 Apr 29;100(9):5461-6
12704240
J Anat Physiol. 1916 Jan;50(Pt 2):111-30
17233054
Trends Neurosci. 1993 Nov;16(11):444-7
7507614
J Hum Evol. 2003 Jan;44(1):3-10
12604300
Nature. 2002 Jan 10;415(6868):134-5
11805823
Behav Neurosci. 1993 Jun;107(3):411-9
8329131
Brain Behav Evol. 2000 Oct;56(4):204-11
11154999
Behav Brain Sci. 2001 Apr;24(2):263-78; discussion 278-308
11530543
Rev Neurol. 1999 Dec 1-15;29(11):1075-82
10637875
Prog Brain Res. 1997;114:553-66
9193166
Curr Biol. 2003 Jan 21;13(2):R65-7
12546808
J Biomech. 1982;15(3):141-54
7096367
Nature. 2001 May 10;411(6834):189-93
11346794
Brain Behav Evol. 1990;35(4):185-94
2379080
Science. 1999 Apr 23;284(5414):629-35
10213683
J Hum Evol. 1997 May;32(5):423-48
9169992
Am J Phys Anthropol. 2001 Feb;114(2):163-5
11169906
Folia Primatol (Basel). 1996;66(1-4):209-25
8953761
J Anat. 1987 Feb;150:191-210
3654333
Behav Neurosci. 1986 Aug;100(4):443-54
3741598
Proc Natl Acad Sci U S A. 2001 Mar 13;98(6):2979-84
11248017
Prog Brain Res. 1997;114:227-49
9193147
Brain Behav Evol. 1998;51(4):230-8
9553695
Folia Primatol (Basel). 1981;35(1):1-29
7014398
Philos Trans R Soc Lond B Biol Sci. 1992 Aug 29;337(1280):185-91
1357693
Nature. 2001 Feb 8;409(6821):710-4
11217859
Science. 1995 Jun 16;268(5217):1578-84
7777856