Organization of the diencephalon ventrothalamic area in the sturgeons

Cytoarchitectonics of ventrothalamic area of the diencephalon of the sturgeons was studied in four species of the sturgeons, the great sturgeon Huso huso L., the Kura sturgeon Acipenser guelden-staedtii persicus n. Kurensis Belyaeff, the Caspian sturgeon, Ac. stellatus Pall., and the barbel sturgeon Ac. nudioventris Lov. using Nissl staining and Bilschowski impregnation techniques in Viktorov’s modification. The ventral thalamus of the sturgeons was found to include seven nuclei: ventromedial, ventrolateral, intermediate and ventral thalamic nuclei, thalamic eminence, and nuclei of ventral and medial optic tracts. The main attention was paid to comparative analysis of this area in the sturgeons and other actinopterygian fish. The structures common to all ray-finned fish or only to the lower teleosts and ganoids as well as characterizing only the sturgeons.