Large-scale cortex-core structure formation in brain organoids
  Brain organoids recapitulate a number of brain properties, including neuronal
diversity. However, do they recapitulate brain structure? Using a hydrodynamic
description for cell nuclei as particles interacting initially via an
effective, attractive force as mediated by the respective, surrounding
cytoskeletons, we quantify structure development in brain organoids to
determine what physical mechanism regulates the number of cortex-core
structures. Regions of cell nuclei overdensity in the linear regime drive the
initial seeding for cortex-core structures, which ultimately develop in the
non-linear regime, as inferred by the emergent form of an effective interaction
between cell nuclei and with the extracellular environment, as mediated by a
dynamic cytoskeleton. Individual cortex-core structures then provide a basis
upon which we build an extended version of the buckling without bending
morphogenesis (BWBM) model, with its proliferating cortex and constraining
core, to predict foliations/folds of the cortex in the presence of a
nonlinearity due to cortical cells actively regulating strain. In doing so, we
obtain asymmetric foliations/folds with respect to the trough (sulci) and the
crest (gyri). In addition to laying new groundwork for the design of more
familiar and less familiar brain structures, the hydrodynamic description for
cell nuclei during the initial stages of brain organoid development provides an
intriguing quantitative connection with large-scale structure formation in the
universe.
