[Neuroanatomical basis of behavior: history and recent contributions]

Abstract

Considering the most recent contributions, the limbic cortical areas, originally known as the greater limbic lobe, besides the cingulated and the parahippocampal gyri also includes the insula and the posterior orbital cortex. In contrast to the nonlimbic cortical areas that project to the basal ganglia (particularly over the dorsal aspects of the striatum, constituted by the caudate nucleus and by the putamen), the limbic cortical areas are characterized by projecting to the hypothalamus and also to the ventral striatum (particularly to the nucleus accumbens). Once all the striatum projects to the globus pallidus which projects to the thalamus and then to the cortex, generating cortical-subcortical reentrant circuits, while the dorsal striatum and pallidum related cortico-subcortical loops are involved with motor activities, the ventral cortical-striatal-pallidal system is particularly related with behavior functions. The extended amygdala (central medial amygdala, stria terminalis or dorsal component, ventral component, and bed nucleus of stria terminalis) receives inputs primarily from the limbic cortical areas, is particularly modulated by the prefrontal cortex, and receives also direct connections from the thalamus that enables the amygdala to generate nonspecific and quick responses through its projections to the hypothalamus and to the brainstem. The ventral striatal-pallidal and the extended amygdala are then two basal forebrain macro-anatomical systems, that together with the basal nucleus of Meynert and with the septal-diagonal band system, constitute the main structures that are particularly connected with the limbic cortical areas, and that altogether project to the hypothalamus and to the brainstem which give rise to the autonomic, endocrine and somatosensory components of the emotional experiences, and that regulate the basic activities of drinking, eating, and related to the sexual behavior.