Resumo

MUZIO, Rubén N.. Aprendizaje en Anfibios, el eslabón perdido: Un modelo simple cerebral en el estudio de conductas complejas. Cuad. herpetol. [online]. 2013, vol.27, n.2, pp.87-100. ISSN 1852-5768.

The brain of phylogenetically older groups (such as fish and amphibians) does not present neocortex, taking a simpler organization than that observed in mammals. Particularly, amphibians are a key group in vertebrates as they represent the transition from water to land. From the perspective of brain-behavior evolution, this group is especially useful to elucidate what the implications of such a transition might have had on brain organization. Therefore, amphibians offer the unique opportunity to find basic mechanisms of a wide variety of behaviors without a strong cortical modulation. This article includes a description of three procedures in amphibians that we have developed in our laboratory to study several aspects of learning, both appetitive as aversive, and their neural basis. First, learning in a runway situation, in which the medial pallium (homologous to the mammalian hippocampus) is functionally involved in the extinction of response. Second, spatial learning, where activation of the medial pallium also play an essential role. Finally, several aversive learning situations of avoidance, where the striatum (homologous to the mammalian amygdala) would assume an important functional role. As a whole, the study of the amphibian model is beginning to provide keys about the basic neural mechanisms of these learned behaviors. Moreover, all these data show that these learning processes are very general among different groups of vertebrates, suggesting that these characters have been highly conserved in the course of evolution.

Palavras-chave : Amphibians; Rhinella arenarum; Learning; Pallium medial-hippocampus; Striatum-amygdala; Brain-behavior evolution.