Neurogenesis, Differentiation, and Cell Fate Specification These studies suggest that temporal regulation of electrical signals is critical for neocortical development ( Figure 1). Further studies revealed that electrical signaling is also crucial for early cortical development including neuronal proliferation, differentiation, and migration ( Spitzer, 2006). The roles of electrical signaling in axonal and dendritic growth and remodeling during late developmental stages have been intensely studied ( Katz and Shatz, 1996 Price et al., 2006). Electrical Signaling During Neocortical Development Finally, we discuss the potential application of emerging optical techniques to address remaining issues related to the physiological mechanisms of neocortical development and the pathophysiology of channelopathies in vivo. Next, we discuss possible links between abnormal electrical signaling caused by dysfunction of ion channels or transporters and neurological disorders. In this review, we summarize how ion channels and transporters regulate electrical properties and Ca 2+ signaling during neocortical development, focusing on excitatory neurons. Recent reports showed that dysfunction of ion channels or transporters disrupts neocortical development by altering electrical properties and Ca 2+ signaling and may be linked to neurological disorders ( Kullmann, 2010 Schmunk and Gargus, 2013 Guglielmi et al., 2015 Heyes et al., 2015 Kahle et al., 2016). As well as genetic programs, electrical activity and Ca 2+ signaling are also crucial for these processes ( Katz and Shatz, 1996 Spitzer, 2006). The molecular mechanisms of neocortical development have been intensely studied ( Tessier-Lavigne and Goodman, 1996 O’Leary and Nakagawa, 2002 Hevner, 2006 Molyneaux et al., 2007 Kawauchi and Hoshino, 2008 Kawauchi, 2012 Marín, 2012). Finally, neurons stop migration below the MZ, and elongate dendrites and axons ( Tissir and Goffinet, 2003 Mizuno et al., 2007, 2014). Then, migrating neurons change their shape at the border between the IZ and the cortical plate (CP) to a bipolar shape with long leading processes and short trailing processes, and migrate along the radial axis toward the cortical surface ( Nadarajah et al., 2003). Neocortical excitatory neurons slowly move in the subventricular zone (SVZ) and the intermediate zone (IZ) with small processes in multiple directions (multipolar migration) ( Tabata and Nakajima, 2003). The newly born neurons migrate toward the marginal zone (MZ).ĭuring migration, neurons dynamically change their morphology. Intermediate progenitors then produce or differentiate into excitatory neurons ( Hevner, 2006). During neurogenesis, intermediate progenitors are produced from radial glia. Neocortical excitatory neurons are produced from neural progenitor cells in the ventricular zone (VZ). Its laminar structure is formed in an “inside-out” manner layer 6 is formed first, followed by formation of upper layers above the lower layers. The cerebral cortex consists of six layers. Precise formation of neocortical circuits is essential for brain function.
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