This chapter is a continuation of our previous study of the forebrain evolution in vertebrates using some new tests allowing evolutionary transformations to be revealed. As such tests, we chose the expression of calcium-binding proteins as neuronal functional markers and the metabolic activity of cytochrome oxidase, characterizing the level of neuronal activity. Here, we report the results of our study of the thalamic visual and auditory centers in reptiles (turtles, Emys orbicularis and Testudo horsfieldii) and birds (pigeon, Columba livia) with a special focus on differences in their parallel visual thalamofugal and tectofugal channels and auditory lemniscal and extralemniscal channels. A comparison with data obtained in other Sauropsida amniotes was drawn to elucidate the role of phylogenetic and functionally adaptive factors determining variable distribution of calcium-binding proteins and metabolic activity, as well as to identify evolutionary conservative and plastic traits in the organization of these thalamic sensory centers.
Part of the book: Evolutionary Physiology and Biochemistry