Basic Organization of Territories That Become Sequentially Involved After Initial Involvement of Brainstem Nuclei with Diffuse Projections

Abstract

The cerebral cortex is the overarching superordinate structure of the human CNS. It is not a uniform entity but consists of two fundamentally different types of gray matter, i.e., the expansive and, for the most part, uniformly composed neocortex (Fig. 6.1a, yellow, light and deep orange, light and deep blue shading) and a small and heterogeneous allocortex (Fig. 6.1a, red shading). A transition region mediates between the two (Fig. 6.1a, green shading) (Braak 1980; Nieuwenhuys 1994; Amunts and Zilles 2001; Zilles and Amunts 2010). The neocortex is chiefly responsible for processing and planning the interactions with the external world. It receives abundant somatosensory, visual, and auditory data, and it influences, at the same time, somatomotor activity that impinges on the organism’s environment (Fig. 6.1c). The neocortex, which takes up approximately 95 % of the total surface area of the human cerebral cortex, generally shows a six-layered organization, with the exception of a few regional variations.