Abstract

I agree with the view expressed in the target article that the early structural organization of the mammalian neocortex (the primordial neocortical organization) is different from its final one and resembles the more primitive organization of reptilian cortex. During the early development of the neocortex, a distinctly mammalian multilayered pyramidal-cell plate is introduced within a more primitive reptilian-like cortex, establishing simultaneously layer I (marginal zone) above it and layer VII (subplate zone) below it. This multilayered pyramidal-cell plate represents a recent mammalian innovation in the evolution of the cerebral cortex of vertebrates. Hence, the term neocortex is preferable to isocortex.