The evolution of contralateral control of the body by the brain: is it a protective mechanism?
Contralateral control, the arrangement whereby most of the human motor and sensory fibres cross the midline in order to provide control for contralateral portions of the body, presents a puzzle from an evolutionary perspective. What caused such a counterintuitive and complex arrangement to become dominant? In this paper we offer a new perspective on this question by showing that in a complex interactive control system there could be a significant net survival advantage with contralateral control, associated with the effect of injuries of intermediate severity. In such cases an advantage could arise from a combination of non-linear system response combined with correlations between injuries on the same side of the head and body. We show that a simple mathematical model of these ideas emulates such an advantage. Based on this model, we conclude that effects of this kind are a plausible driving force for the evolution of contralateral control.
a Department of Physics and Astronomy , University of British Columbia , Vancouver , Canada.
Lorne
L
Whitehead
Saleh
S
Banihani
D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000502:physiology*; D007839:Functional Laterality; D006801:Humans; D008954:Models, Biological; D017711:Nonlinear Dynamics; D013534:Survival / Q000502:physiology*; D014947:Wounds and Injuries / Q000503:physiopathology