Neurodevelopment and degeneration

Abstract

highlight these contributions in subcategories, to provide our readers with a comprehensive overview. Basic Unit AssemblyAs the recognized building block of the nervous system, the neuron is compartmentalized into axons and dendrites that mediate information processing. Another major cell type, glia, though they do not exhibit major polarized features, play significant roles in regulating neuronal development and function. The origin of these cells and how they are generated from NSCs have long been an active area of research. Song et al. describe the development of adult hippocampal NSCs and their progeny [1] . These NSCs exhibit distinct features during different developmental stages. Understanding the mechanism of their specifi cation, development, and regulation provides cues to their therapeutic potential in regard to neuronal regeneration and degeneration. In addition, activity-dependent mechanisms and the required elements from the niche microenvironment for regulating the development of these NSCs are illustrated [1] . Regulatory factors such as neurotransmitters, morphogens, and transcription factors are thoroughly discussed [1] .Once specifi ed and polarized, neuronal compartments such as axons and dendrites begin to undergo differentiallyregulated growth. Ye et al., using both mammals and fl ies as models, discuss the underlying mechanisms regulating axon and dendrite growth [2] . Two models, dedicated and bimodal mechanisms, have been proposed and are reviewed. Whereas the dedicated regulators like BMP7 or Rac1 affect only the growth of either axons or dendrites, bimodal regulators like Sema3A execute binary functions that promote axon or dendrite growth while inhibiting the other [2] . Accompanying growth, differentiated axons exhibit guidance properties that Liu et al. review in great detail [3] . A subject of interest for many years, axon guidance is crucial for neuronal function and the microtubule dynamics at the growth cone of axons has been considered as a classical paradigm for understanding cell motility and dynamics [3] .In addition to neurons, a plethora of evidence has suggested that glia play pivotal roles during