Room 128 - 129, 16:30
With Bruno Mota, Instituto de Física - Universidade Federal do Rio de Janeiro
Abstract:
The mammalian cerebral cortex is a morphologically complex structure spanning a wide range of sizes and shapes across species. I will show that, in spite of all this diversity, cortical shape can be universally and explicitly expressed as the hierarchical composition of folded structures of different sizes. Using a new set of theory-inspired morphological variables that capture shape and size as functions of length scale, I show that for cortices of 11 different primate species, this composition process recapitulates in all cases a common scale-invariant morphometric trajectory. This indicates these cortices are approximations of a single archetypical fractal shape, differing solely on the range of length scales for which the approximation holds. These results suggest the existence of a universal gyrification mechanism operating on all scales, and that there is only a small number of effective degrees of freedom through which Darwinian natural selection can select cortical shapes. This new way of expressing morphology can be used to parametrize stages of cortical development and aging, and to characterize different conditions such as Zika-induced microcephaly and Alzheimer's. We thus hope that in the future this systematic approach may help elucidate the processes underlying cortical gyrification in health and disease.