Substrato neuroanatômico dos circuitos cognitivos e visceromotores dos córtices pré-límbico e infralímbico do córtex pré-frontal medial: descrição das suas projeções anterógradas e interações com complexos subcorticais no primata Callithrix jacchus

Abstract

The interest of science, and particularly of the fields of biology and neuroscience, is in understanding the functioning of the nervous system in relation to the products of brain activity, such as cognition and behavior, has led to the development of several investigations that put their focus of study in the frontal lobes, especially in the prefrontal regions. The cortex has been functionally studied; however, the anatomical projections of the axons and the description of the neural networks that originate in these areas of the brain have brought more interest in some than in others. The medial region of the prefrontal lobes has not received sufficient attention in the approach and detail of its projections and relations with the subcortical structures of the brain. Therefore, this research proposal is aimed to descrive the neuroanatomic substrate of the cognitive and visceral-motor circuits of the prelimbic and infralimbic cortex of the medial prefrontal cortex and their projections and interactions with subcortical complexes in Callithrix jacchus primate (knows like marmoset); delimited to areas and nucleus of the diencephalic, amygdaloid and hippocampus complexes. The common marmoset is a neotropical primate of the new world, and the absence of telencephalic gyrus in its brain structure favors the mapping of neuronal fibers. The biotinylated dextran amine was employed as an anterograde tracer; deposited in the pre-limbic (PL) and infralimbic (IL) cortices. Among the planned hypotheses, it was proposed that there is an organized and exclusive distribution in the directionality of the fibers towards the subcortical regions associated with the three complexes of interest, in primates, a fact that was possible to corroborate from the results obtained. There was an evident pattern of rostrocaudal distribution of the fibers within the subcortical nuclei, with medial orientation. Within this distribution, the fibers coming from the infralimbic cortex were found to be more clustered within the areas than those originating in the prelimbic cortex, which was more dispersed. Most areas of the amygdala received fibers from both cortices. In the diencephalon, the four regions received projections from the prelimbic region, while the infralimbic fibers were restricted to the thalamus, hypothalamus, and epithalamus in general at different densities. However, it was observed that within the hippocampal complex there were restricted fibers, exclusive to the prelimbic cortex projections. Our data contribute significantly to the description and understanding of the specific connectivity of the limbic regions of the medial prefrontal cortex. These and other findings in this research stand out for their originality, as well as the pioneering methodological characteristics in achieving their objective; facts that, as a novelty, contribute to the study of the morphological correlates of the anatomical-functional activity in the brain.