Caracterização morfoquantitativa e neuroquímica do complexo coclear no encéfalo de morcego (Artibeus planirostris)

Abstract

The auditory system is extremely important for the survival of the species. Those that live in your natural environment, as well as those created under controlled conditions of laboratory need the hearing to detect dangers such as predators and motor vehicles, respond to vocalizations of animals of the same or other species. The ear is called a vestibulocochlear organ, because it participates directly in hearing and in maintaining balance. Spatial navigation by chiroptera is widely associated with the mechanism of echolocation, which consists of the emission of sound waves by the vocal apparatus and consequent echo reflex, captured by the vestibulocochlear apparatus. Although several studies address the functional dynamics of the chiroptera echolocation systems, few papers are dedicate to a morphological analysis of the neural centers involved in the processing of such information. The present study aims to describe the morphoquantitative and neurochemical organization of the cochlear complex in bat Artibeus planirostris brains. Using the Nissl’s method all classical subdivisions described up to the present in other species were identified: ventral cochlear nucleus (anterior part, posterior part and granular layer) and dorsal cochlear nucleus (deep layer, fusiform layer and molecular layer). The neurochemical analysis of the calcium binding proteins by means of the immunofluorescence technique allowed to identify the presence of immunoreactive terminals and pericals to CB, CR and PV in different ways, presenting specificities in each part of the cochlear complex. Comparing vertebrates, the present study provides a first detailed description of the morphoquantitative aspects of the bat Artibeus planirostris, which was very similar to the characteristics found in rodents, specifically the rat and the chinchilla. The neurochemistry is different to human and non-human primates, and may be a direct relation with the echolocation used by the experimental model.