A quantitative approach to cytoarchitectonics. I. The areal pattern of the cortex of Tupaia belangeri.

The cortical map of Tupaia belangeri, evaluated with an automatic quantitative procedure using the Micro-Videomat (Zeiss), shows a well differentiated allocortex and periallocortex with 19 areas, and proisocortex and isocortex with 20 areas. The boundaries of the different areas are based on quantitative differences and the areal pattern of the cortex is, in most cases, compatible with physiological results found in the literature. Tupaia belangeri has a cortex which is largely dominated by primary and secondary sensory areas in its iscortical part and by the impressive visual system. The well differentiated allo- and isocortex show conditions more similar to prosimians than to insectivores, especially when considering the occurrence of primary and supplementary regions. Quantitative analyses of the separate areas with a higher resolution (Zilles et al., in prep.) are necessary in order to provide a basis for further comparative investigations of the Tupaia cortex.