Normal and Abnormal Development of the Cortex

In keeping with IPSEN's growing interest in the neurosciences, the Fondation organized a meeting dealing with the topic of normal and abnormal cortical development, which took place in Paris, on October 14, 1996. This was the 7th of a series of colloquia devoted to the neurosciences. The topics covered included pre-migratory events controlling cell proliferation, neuronal migration, early cortical plasticity including cell death and development of axonal connections, and genetic and epigenetic effects on cortical teratogenesis. It is clear that the ultimate structure and functional capacity of the cerebral cortex are determined, at least in part, by developmental events taking place very early, even before neuronal migration. Caviness and colleagues suggest that the regulation of the G, portion of the cell cycle may be an important mechanism for determining neuronal class and pre-migratory positional encoding in the pseu dostratified periventricular germinal zones. Similarly, Kennedy and Dehay emphasize the role of pre-migratory cell cycle kinetics in the cytoarchitectonic differentiation of the cortex, but also consider some post-migratory events important to cortical differentiation. Among the post-migratory events control ling cortical differentiation are these thalamo-cortical connections, lind some of the rules governing this thalamo-cortical interaction was reviewed by Dennis O'Leary at the meeting. ' Three papers deal with the topic of neuronal migration. The paper by Hat ten and collaborators reviews the role of astrotactin and its cellular and molecu lar properties.