Minicolumn size and human cortex.
Minicolumns in primates are small when compared with those of other mammals, both in absolute and relative terms. The data suggest that minicolumns in the earliest primates were especially narrow and increased in accordance with encephalization so that the largest minicolumns in this mammalian order are found in apes and humans. Among the evolutionary strategies that led to the successful human brain was a combination of enhanced cortical volume based on increases in the number of ontogenetic units, along with enlargement of the individual minicolumns. However, continued encephalization of the large human brain presents serious problems that may limit future growth. When further increases in brain size can no longer be sustained, the alternative for further adaptations will have to be done at the level of brain organization. A downsizing of minicolumns may be among those responses. This has the advantage of permitting increases in the number of processing units without adding surface area. However, it is argued that narrow minicolumns process information differently, which raises questions about the relation between minicolumn size and behavior. There is evidence that minicolumns may be smaller in extant humans within selected populations, and the implications of this are briefly considered.
College of Social Work and Department of Anthropology, University of South Carolina, Columbia, SC, USA. buxhoeve@gwm.sc.edu
Daniel P
DP
Buxhoeveden
D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans