Metabolic Activity of Pigeon Thalamic and Telencephalic Auditory Centers

Distribution of activity of mitochondrial oxidative enzyme cytochrome oxidase (CO) was studied in the thalamic (Ov) and telencephalic (field L) auditory centers of the pigeon Columbia livia. Different levels of CO activity are found in the core and belt of the centers: the high CO activity in the core of Ov (nCe) and telencephalic field L2 and the much lower or absent in the peripheral regions (Ovl, Ovm, SPO and L1 and L3). Comparison of our data with those of various avian and reptile species confirms the concept of the common plan of rostral auditory centers in sauropsid amniotes by the principle of the center-periphery (core-belt), which is characteristic of the corresponding mammalian centers. The separation of the central and peripheral parts of these centers is better pronounced in birds than in reptiles.