Cellular and molecular introduction to brain development

Abstract

Advances in the study of brain development over the last decades, especially recent findings regarding the evolutionary expansion of the human neocortex, and large-scale analyses of the proteome/transcriptome in the human brain, have offered novel insights into the molecular mechanisms guiding neural maturation, and the pathophysiology of multiple forms of neurological disorders. As a preamble to reviews of this issue, we provide an overview of the cellular, molecular and genetic bases of brain development with an emphasis on the major mechanisms associated with landmarks of normal neural development in the embryonic stage and early postnatal life, including neural stem/progenitor cell proliferation, cortical neuronal migration, evolution and folding of the cerebral cortex, synaptogenesis and neural circuit development, gliogenesis and myelination. We will only briefly depict developmental disorders that result from perturbations of these cellular or molecular mechanisms, and the most common perinatal brain injuries that could disturb normal brain development.

Effects of antenatal glucocorticoids on the developing brain

“…At the onset of neurogenesis in the mouse cortex, neuroepithelial cells divide to form RGCs, which are distinguished by their expression of Pax6 and are located in the ventricular zone (VZ), adjacent to the lateral ventricles 49,56 . RGCs can divide symmetrically to give rise to two RGCs or asymmetrically to give rise to an RGC (inner RGC or iRGC) and to cells in the second proliferative population in the subventricular zone (SVZ) located above the VZ.…”

“…In both human and mice the second proliferative population in the SVZ consists of two distinct cell types, outer RGC cells (oRGCs) and intermediate progenitor cells (IPCs), although the relative proportions of each cell type differs between humans and lower species. IPCs and oRGCs divide to give rise to the majority of neurons in the cortex 49,57–59 . The cells born from progenitors in the VZ and SVZ ultimately migrate and give rise to the exquisitely organized six layers of neurons that populate the cortical plate.…”

“…Essential to the development of the individual layers of the cortex is temporal patterning, which is controlled by intrinsic processes, intracellular communication and environmental influences 60,61 . Throughout brain development, neurons create connections through the process of synaptogenesis, which is essential for the establishment of cortical architecture, and this continues postnatally 49 .…”

“…In addition to neurons, glial cell types, including astrocytes and oligodendrocytes (OLGs), populate the cortex and account for the majority of cells in the brain 49 . These cells are not only responsible for maintaining homeostasis but also play an essential role in cortical development 49,62,63 .…”

21st Century Research in Child Neurology

“…The first paper "Cellular and molecular introduction to brain development" (Jiang and Nardelli, 2016) The second paper "Neuronal migration disorders" (Stouffer et al, 2016) gives an overview of neuronal migration disorders with a focus on the role of cytoskeleton in abnormal migration, and on epilepsy as a major consequence of aberrant neuronal positioning.…”