The organization of neural systems in the primate cerebral cortex

The primate cerebral cortex is a sheet composed of many distinct areas. Each of these areas receives a large number of afferent inputs from other cortical areas (and elsewhere) and in return issues a large number of output projections. The cortex is thus innervated by a very large number of cortico-cortical connections, so that the areas and their interconnections form a network of startling complexity. The complexity of this network presents a formidable topological problem that hinders understanding of its organization. Recently, however, an optimization analysis has been applied to the connections between visual cortical areas. This optimization analysis derived a structure for the cortical visual system, a system whose organization has been extensively explored, that is consistent with known organizational features. This paper concerns an application of the same approach to the cortico-cortical connections of other major sensory systems in the primate brain, and to the connections of the entire cerebral cortex, whose organizations have not been extensively explored. The latter analysis suggests the gross topological organization of the cortical information processing system of this animal, and shows the 'place' of individual areas within this organization. The results may be suggestive for further theory and experiment.