Comparative cytoarchitectural analyses of striate and extrastriate areas in hominoids.
The visual cortex is the largest sensory modality representation in the neocortex of humans and closely related species, and its size and organization has a central role in discussions of brain evolution. Yet little is known about the organization of visual brain structures in the species closest to humans--the apes--thus, making it difficult to evaluate hypotheses about recent evolutionary changes. The primate visual cortex is comprised of numerous cytoarchitectonically distinct areas, each of which has a specific role in the processing of visual stimuli. We examined the histological organization of striate (V1) and 2 extrastriate (V2 and ventral posterior) cortical areas in humans, 5 ape species, and a macaque. The cytoarchitectural patterns of visual areas were compared across species using quantitative descriptions of cell volume densities and laminar patterns. We also investigated potential scaling relationships between cell volume density and several brain, body, and visual system variables. The results suggest that interspecific variability in the cytoarchitectural organization of visual system structures can arise independently of global brain and body size scaling relationships. In particular, species-specific differences in cell volume density seem to be most closely linked to the size of structures in the visual system.
de Sousa
Alexandra A
AA
Center for Advanced Study of Hominid Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA. a.sousa@ucl.ac.uk
Sherwood
Chet C
CC
Schleicher
Axel
A
Amunts
Katrin
K
MacLeod
Carol E
CE
Hof
Patrick R
PR
Zilles
Karl
K
D000818:Animals; D005075:Biological Evolution; D001931:Brain Mapping; D002452:Cell Count; D048429:Cell Size; D015186:Hominidae / Q000033:anatomy & histology* / Q000145:classification*; D006801:Humans; D009474:Neurons / Q000502:physiology; D013045:Species Specificity; D014793:Visual Cortex / Q000166:cytology*; D014794:Visual Fields; D014795:Visual Pathways