Brain development

Mouse models have been central to achieving our current understanding of the molecular and cellular mechanisms governing brain development. Brain morphogenesis follows an integrated series of developmental steps: neural induction, neurulation, proliferation, migration, differentiation, regionalization, axonal outgrowth, synaptogenesis, and apoptosis. Newly generated cells migrate radially and tangentially from their sites of origin in primordial brain divisions to generate increasingly mature structures through pre- and postnatal development, with emphasis here given to the cerebral cortex and cerebellum. Immense neuronal diversity is achieved by graded and combinatorial gene expression in various sectors of proliferative cell populations over time. Complex intrinsic and extrinsic factors, such as thalamocortical and corticofugal signaling, update and adapt the brain's functional architecture particularly during critical periods. Studies using transgenic mouse models and advances in both adult and developmental mouse brain atlases will continue to elucidate mechanisms governing normal and pathological mammalian brain development.