Geometric principles governing regional organization of the mammalian brain

COEX 

Brain development is driven by numerous physiological processes, such as cell migration and neuronal differentiation, which ultimately shape the cellular, anatomical, and functional properties of the brain. Classically, spatial variations in these properties are delineated using discrete boundaries to subdivide anatomically and/or functionally homogeneous cortical and subcortical areas. However, there is no consensus to date as to which specific property should be prioritized in defining these regional boundaries, and the reliance on largely descriptive approaches has resulted in a plethora of different brain parcellations. In this talk, I will describe a new unified geometric-based approach that uses brain geometry to define regions in both the cortex and subcortex of human and various non-human mammalian species. I will show that the resulting geometric parcellations produce regions that are more homogeneous than most existing parcellations in terms of capturing diverse anatomical, functional, cellular, and molecular brain properties, and that the approach can easily be generalized to other mammalian species (e.g., primates, rodents, rabbits, treeshrews) for which no parcellations exist. Finally, I will show that the geometric approach underpinning this parcellation is tied to a generative reaction-diffusion mechanism that describes how the concentration of chemicals (e.g., morphogens) diffuses in space to enable the formation of patterns that shape regional organization.