Variations in the fissural pattern of the cerebral neocortex of the spider monkey (Ateles).

Data are reported on the range and variety of fissural patterning in 40 cerebral hemispheres from 22 specimens of spider monkeys (Ateles). The hemispheres are categorized according to a number of criteria, including proximity of the central sulcus to neighboring sulci, whether certain other sulci are joined or separated from each other, and the presence and location of idiosyncratic fissures. Interhemispheric variability was found to be as pronounced within as between specimens. The study revealed a wide variability in fissural patterns of primate brain specimens and a topological significance of many sulci in that they demarcate functional subdivisions of either somatosensory or somatomotor cortex.