Organização citoarquitetônica, neuroquímica e morfométrica do Claustro

Abstract

The Claustrum (Cl) forms part of the basal ganglia and is anatomically constituted of two main subdivisions: dorsal or insular Cl, and the medial ventral Cl located in the piriform cortex. The shape of the Cl varies among species and its size increases in proportion to the volume of the neocortex. The Cl nucleus can play a key role in the processing of information in the brain, correlated to different activities developed by the activation of the sensory cortex that interconnects with different sensations. It is divided into three functional components: an anterodorsal connected to the somatosensory cortex and the motor cortex, a posterior dorsal connected to the visual cortex and a ventral area connected to the auditory cortex. While the exact function of Cl remains speculative, studies in rat brains have attributed a multimodal integrating role in relation to the connections attributed between the Cl and the cerebral cortex (cx), as various functions, such as somatosensory, visual and auditory can be associated with this nucleus. It is possible to consider differences among species regarding the neurochemical organization and Cl connections. For the approach on the relationship between the Cl and the Endopiriform nucleus (En) raises some discussion, as this correlation between the two nuclei can be approached in a number of ways, such as some probable functional relations. Thus, with the purpose of describing a cytoarchitecture and the neurochemistry of the nucleus, coronal sections of the brains of the bat Artibeus planirostris, were stained by Nissl method and sections submitted to the immunofluorescence technique presenting calcium binding proteins Calbindin (CB), Calretinin (CR) and Parvalbumin (PV), to delimit and observe the expression of these proteins in the Cl/En. The immunoreactivity to CB was not expressed in the subdivisions of Cl. CR was detected in a few Cl cells at middle level, were as immunoreactivity to PV was perceived conspicuously at the rostral, middle and caudal levels of Cl/En. Over all, in view of the strategic position of the CI, the associated functional and hodologic evidences in several studies, we believe that the study of the morphology of this area in bats can truly help elucidate the role of Cl in the nervous system and at the same time understand the pathways permeated by the evolution of subcortical nuclei.