Fig. 1: Overview of brain development.
From: Neurodevelopmental disorders—high-resolution rethinking of disease modeling
A The schedule of major developmental processes during brain development in mice (upper part) and humans (lower part). B Anatomical correspondence between developing brain regions in the early embryonic brain and the postnatal brain. C Schematic representation of differentiation strategy during brain development, starting from undifferentiated neuroepithelial cells (gray) to more differentiated radial glia cells, intermediate progenitors, and neurons. The timeline in gestational weeks (GW) is not-to-scale. Subtype differentiation within brain regions (such as upper/deeper layer principal neurons in the cortex or different neuropeptide-specific neurons in the hypothalamus) is organized rather orthogonally to areal signatures (such as rostro-caudal differentiation) and have strong temporal dependence. For instance, in the cortex, deeper layer principal neurons are produced as early as GW9, whereas switch to upper layer principal neurons happens at GW14-16. Colored cells that appear before the actual branching indicate that the cell fate is primed, mainly by epigenetic mechanisms. D Schematic representation of differentiation strategy for the ganglionic eminence that generates telencephalic inhibitory neurons. The medial ganglionic eminence is expanded to show an example for differentiation into classes, families, and subtypes of neurons.
