Ontwikkeling en ontwikkelingsstoornissen van het humane brein. II. Ontwikkeling van de hersenschors en de grote baansystemen

- In the development of the cerebral cortex, two phases can be distinguished: (a) the formation of the preplate, a superficial layer essential for a normal lamination of the cerebral cortex; (b) the formation of the cortical plate. - The cortical plate divides the preplate into a superficial marginal zone (the future layer 1) and the subplate. The transient subplate is important for the formation of thalamocortical projections. - Most cortical neurons arise in the ventricular zone of the pallium and migrate along radial glial cells (radial migration) to the cortical plate. - The gamma-aminobutyric acid (GABA)ergic cortical interneurons, however, originate from the ganglionic eminences and reach the cerebral cortex through tangential migration. - The thalamocortical projections and the pyramidal tract are formed late in the embryonic period, whereas the corpus callosum only arises during the foetal period. Myelinization begins in the second trimester of pregnancy.