Fig. 3.

Calcium and excitatory neuroblast migration. Excitatory neuroblasts undergo radial migration along RGC fibers to reach their final laminar destination. Migratory neuroblasts exiting the VZ display high frequency spontaneous calcium transients. As they enter the SVZ, neuroblasts adopt a multipolar morphology and exhibit low amplitude calcium events. Calcium transients during neuroblast migration are largely mediated by extracellular agonists like BDNF, which activates TrkB, by neurotransmitter receptors (e.g. NMDARs, GABARs), and by downstream activation of VGCCs. Glutamate influences radial migration by inducing calcium influx primarily through NMDARs. Depolarization via GABARs and calcium influx via VGCCs also control radial migration. Emerging evidence suggests that calcium transients propagating through RGC fibers may also contribute to the regulation of neuroblast migration into the cortical plate.