Origin and Evolution of the Vertebrate Telencephalon, with Special Reference to the Mammalian Neocortex

1 Introduction There is little doubt that the vertebrate brain is the most complex structure we know. As with any complex structure, there is the immediate question about its origins. Howcouldsuchacomplexdesigndevelopfromthesimplestmulticellular animals? This problem has pervaded the study of evolutionary biology since its beginnings. Although Darwin (1859, 1871) proposed an impeccable mechanism (natural selection) for the gradual transformation of species including human origins, even he s...