ABSTRACT
Philosopher-scientists as far back as Galen (see Changeux, 1986, p. 8) understood that one of the most fundamental organizing principles of the mammalian neocortex is its parcellation into anatomically and functionally distinct areas. Neocortical areas are similar in many ways, including types of cellular constituents, the presence of six cell layers, and the laminar organization of inputs and outputs. Neocortical areas differ from one another as well, along several structural and functional dimensions, including connectivity, topography, and response properties (Seitz, this volume). During evolution, neocortical parcellation produces new areas where they did not previously exist. Although major advances in understanding the brain have certainly been made in the last two centuries, it remains unclear what factors drive the appearance of distinct neocortical areas during either development or evolution (Pallas, 2001). Why has this issue remained so refractory to resolution?
