A quantitative approach to cytoarchitectonics. VII. The areal pattern of the cortex of the Guinea pig.

The cerebral cortex of the guinea pig has been examined by means of a quantitative cytoarchitectonic method (Schleicher et al. 1978; Zilles et al. 1978a). In this method, a computer-controlled automatic image analyzer determines the grey level index of microscopic fields measuring 50 X 50 mu m in Nissl-stained sections by a systematic scanning procedure. Computer plots of serially sectioned histological slides from three hemispheres were produced by printing selected ranges of grey level indices. The delineation of cortical areas was worked out in these plots based on quantitative criteria. Cortical maps of the areal pattern were reconstructed graphically. The resulting cortical map of the guinea pig differs from that of Rose (1912), but it corresponds to the results of Friede (1960) and is in agreement with neurophysiological studies. In general, the areal pattern of the guinea pig is similar to that of the rat (Zilles et al. 1980), but there are also some differences. These differences are discussed with respect to functional considerations.