Fig. 9.

a. The earliest produced neurons migrate to the deepest cortical layers (dark blue). Subsequently migrating neurons migrate to successively more superficial layers (lighter blues) creating an inside out order of migration. Adapted with permission from Cooper (2008). Trends in Neuroscience, 31(3), 113-19. b. As shown in the first panel, the first neurons migrate from the ventricular zone (VZ) to form the preplate (PP). As shown in the second panel, the next neurons split the PP into the marginal zone (MZ) an the subplate (SP), both transient brain structures. The mature brain, shown in the third panel, has six well developed cortical layers (I-VI), but none of the embryonic structures (MZ, SP, VZ). The intermediate zone (IZ) has become a mature white matter layer (WM). Illustrations by Matthew Stiles Davis reprinted by permission of the publisher from THE FUNDAMENTALS OF BRAIN DEVELOPMENT: INTEGRATING NATURE AND NURTURE by Joan Stiles, Cambridge, Mass.: Harvard University Press, Copyright © 2008 by the President and Fellows of Harvard College