A Universal Scaling Rule for the Morphology of the Cerebral Cortex
Prof. Bruno Mota
Federal University of Rio de Janeiro, Brazil

The mammalian cerebral cortex is probably the most complex structure ever studied by science. At first glance, any attempt to model it from first principles, would seem doomed to failure. Morphologically, there seems to be a clear distinction between folded, or gyrified, cortices, on one hand, and smooth, or lissencephalic, ones on the other. And yet, the fundamental building blocks for the nervous system and its developmental neuro-proliferative program are largely conserved, and comparative neuroanatomical studies strongly suggest the existence of a universal scale-invariant mechanism for the folding of the cortex as a whole.

In search for such mechanism, we have shown that cortical folding in mammals follows a single power-law relation between three morphological variables. This relation in turn is derived from a simple physical model, based on known mechanisms of axonal elongation and the self-avoiding nature of the cortical surface. The model is in excellent agreement with data obtained from the cortices of dozens of diverse mammalian species, as well as hundreds of human subjects. ?Furthermore, preliminary evidence suggests this scaling is also present in individual cortices: when disaggregated into lobes; or across different length scales.

All this regularity implies that, in spite of all the apparent morphological and functional diversity, evolution has in fact only a few degrees of freedom with which to shape a cortex in response to the various constraints and adaptive pressures. In fact, a simple model can be shown to predict all major coarse-grained morphological features of the cerebral cortex from variations in only three developmental parameters: the number of symmetric and asymmetric divisions of progenitor cells in early development, and the average volumetric density of neurons. It is thus possible that much of the diversity in cortical morphology occurs simply through a small number of adjustments in the various rates that characterize neuro-proliferation in mammals.

About the Speaker

Prof. Bruno Mota has a background in cosmology and recently has been working in biophysics, with applications in neuroscience. BA in Physics from Universidade Federal de Minas Gerais (1999), MSc in Physics from Universidade Federal de Minas Gerais (mathematical physics, 2001) and PhD in Physics from Centro Brasileiro de Pesquisas Físicas (Cosmology, 2007). Expertise in two main areas: cosmology, with an emphasis on cosmic topology, general relativity and cosmic microwave background anisotropies; and theoretical physics methods applied to neuroscience, with emphasis on allometry, comparative neuroanatomy, neuronal networks and algebraic measures of connectivity, and morphological and developmental models for the cerebral cortex. Currently an adjunct professor (tenure-track) at the Physics Institute of the Federal University of Rio de Janeiro.

2018-02-05 10:00 AM
Room: A203 Meeting Room
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