The brain of the raccoon (Procyon lotor) in stereotaxic coordinates. I. Macroscopic studies.

Comparative anatomical and physiological studies revealed that the different sensory modalities are represented in the neocortex in topographically determined areas. Comparison of the representation field of the forepaw in different species of carnivores reveals an exceptional enlargement of these area in the somatosensory cortex of the raccoon. In this species the forepaws are of primary importance for the exploration of the environment and of the food. The peculiar structural organization of the somatosensory area initiated detailed studies by physiologists. There are now sufficient maps obtained after stimulation of circumscript areas in the forepaw. In order to study the somatosensory cortex by morphological methods (espec. degeneration and tracer methods) the aim of the present study was to establish in a first step stereotaxic data for the raccoon brain, especially for the neocortex in the macroscopic level. We gave information about the fixation of the raccoon head in a David-Kopf-stereotaxic-instrument and about the position of the brain in the skull. At least the raccoon brain in a dorsal and lateral view related to stereotaxic coordinates is demonstrated. The zero-plane is positioned in the interaural line.