The nervous systems are developed by the proliferation of progenitors in the epithelium, the specification of neurons and glia, the growth and guidance of axons and dendrites, and the development and refinement of electrical and chemical synapses. In the central nervous system (CNS), stem cells reside throughout life in the forebrain, continuing to generate neurons and glia in the subventricular zone (SVZ) surrounding the lateral ventricle and in the dentate gyrus of the hippocampus. The SVZ is known to be the major site of Neurogenesis in the adult mammalian brain. Throughout life neurons spawn from the neural stem cells that are localized in specialized niches. The apical ependymal niche and the basal vasculature niche are …show more content…
There are many similarities between axon guidance and synapse formation. Axons targeting a specific region is essential for proper neural circuit formation, which makes axons a require partner for synaptogenesis. During axon guidance, growth cones navigate the microenvironment and encounter interaction with receptor proteins and cell surface bound ligands in route to their target field. Their ultimate goal upon arrival is to create functional synaptic connections. Synapse formation involves organized cell morphological and structural modifications that are carried out through ligand-receptor interactions, intracellular signaling cascades, and complex filamentous actin remodeling. Studies have revealed that axon guidance molecules play an important role in regulating synapse formation. These signaling molecules are able to determine synaptic sites and regulate the pre-or post-synaptic differentiations …show more content…
Additionally, its postnatal roles include maintaining synaptic plasticity, control of neurotransmission, and regulation of nerve-muscle connectivity. GABA-ergic interneurons during adulthood express reelin. Reelin is known to provide a stop signal at the marginal zone for later born neurons that migrate from the ventricular zone towards pial surface. Reelin in radially migrating neurons of the cerebral cortex and hippocampus serves as a powerful stop signal. The protein has also been noted to be crucial in tangentially migrating cortical interneurons and necessary in regulation of Purkinje cells migration during development of cerebellum