Research Highlight: A new actor in cortical wiring
ENP team leader Alessandra Pierani and her group in collaboration with ENP team leader Thierry Gally reported of a new mechanism controlling the size and wiring of cortical areas devoted to complex functions via the fine regulation of migration and distribution of the first-born cortical neurons, the Cajal-Retzius cells (CRs). Surprisingly, this work revealed that exocytosis dependent on VAMP3, whose function was previously considered to be restricted to non-neuronal cells of the mature brain, modulates the speed of migration of these neurons and orchestrates their signaling activity. This work, published in Current Biology, opens new perspectives that a strict control of migration kinetics of CRs subtypes contributes to the evolution of cortical connectivity.
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Barber, M., Arai, Y., Morishita, Y., Vigier, L., Causeret, F., Borello, U., Ledonne, F., Coppola, E., Contremoulins, V., Pfrieger, F.W., Tissir, F., Govindan, S., Jabaudon, D., Proux-Gillardeaux, V., Galli, T. and Pierani, A. Migration speed of Cajal-Retzius cells modulated by vesicular trafficking controls the size of higher-order cortical areas. Current Biol. (2015), 25, 2466-2478. Epub 2015 Sep 17.
Research Highlight in Nature Reviews Neuroscience (2015), 16, 644-645
Figure 1: The migration speed of Cajal-Retzius (CR) subtypes governs their distribution and signaling activity in cortical areas and, thus, the size of higher-order cortical areas. CR subtypes migrate from signaling centers at the borders of the developing cerebral cortex to cover complementary territories (S-CRs (green), CH-CRs (blue) and PSB-CRs (red)) and emit signals that control the mode of division of progenitor cells (Griveau et al., 2010). Increasing the speed of S-CRs and CH-CRs migration (++) through VAMP3 inactivation results in their invasion of more distant cortical areas (double pointed green and blue arrows). This changes the composition and activity of CRs signaling in embryonic territories at E11 and hence the size of higher-order cortical areas in the postnatal animal (P8). CRs are also involved in the guidance of thalamic afferents (TCA: thalamo-cortical axons).