[New morphologic findings on the microscopic organization of the inferior colliculus in the cat].

The distribution of different cell types has been studied in the cat inferior colliculus. Morphometry by point counting on semi thin sections led to calculate SN (surface of nucleus), Sc (surface of cell), SN/Sc. Two cell types (small and large neurons) are found, their distribution delimits three nuclear formations (dorso-lateralis, dorso-medialis, ventralis). Craniocaudaly, the volume of the ventral formation decreases, while the volume of the dorsal-medial formation increases. The dorso-lateral formation remains constant. Thus the pattern of the morphological differentiation is similar to that of the functionnal differentiation.