RESUMO
The cuneiform nucleus (CUN) is a midbrain structure located lateral to the caudal part of the periaqueductal gray. In the present investigation, we first performed a systematic analysis of the afferent and efferent projections of the CUN using FluoroGold and Phaseolus vulgaris leucoagglutinin as retrograde and anterograde neuronal tracers, respectively. Next, we examined the behavioral responses to optogenetic activation of the CUN and evaluated the impact of pharmacological inactivation of the CUN in both innate and contextual fear responses to a predatory threat (i.e., a live cat). The present hodologic evidence indicates that the CUN might be viewed as a caudal component of the periaqueductal gray. The CUN has strong bidirectional links with the dorsolateral periaqueductal gray (PAGdl). Our hodological findings revealed that the CUN and PAGdl share a similar source of inputs involved in integrating information related to life-threatening events and that the CUN provides particularly strong projections to brain sites influencing antipredatory defensive behaviors. Our functional studies revealed that the CUN mediates innate freezing and flight antipredatory responses but does not seem to influence the acquisition and expression of learned fear responses.
Assuntos
Formação Reticular Mesencefálica , Substância Cinzenta Periaquedutal , Substância Cinzenta Periaquedutal/fisiologia , NeurôniosAssuntos
Humanos , Pneumonia Viral/prevenção & controle , Pneumonia Viral/epidemiologia , Telemedicina , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/epidemiologia , Administração de Caso/organização & administração , Pandemias/prevenção & controle , Transtornos Mentais/psicologia , Saúde Mental , Betacoronavirus , SARS-CoV-2 , COVID-19 , Transtornos Mentais/terapia , Serviços de Saúde Mental/organização & administraçãoAssuntos
Administração de Caso/organização & administração , Infecções por Coronavirus , Transtornos Mentais/psicologia , Pandemias , Pneumonia Viral , Telemedicina , Betacoronavirus , COVID-19 , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Humanos , Transtornos Mentais/terapia , Saúde Mental , Serviços de Saúde Mental/organização & administração , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , SARS-CoV-2RESUMO
BACKGROUND: According to several lines of evidence, the great expansion observed in the primate prefrontal cortex (PfC) was accompanied by the emergence of new cortical areas during phylogenetic development. As a consequence, the structural heterogeneity noted in this region of the primate frontal lobe has been associated with diverse behavioral and cognitive functions described in human and non-human primates. A substantial part of this evidence was obtained using Old World monkeys as experimental model; while the PfC of New World monkeys has been poorly studied. In this study, the architecture of the PfC in five capuchin monkeys (Cebus apella) was analyzed based on four different architectonic tools, Nissl and myelin staining, histochemistry using the lectin Wisteria floribunda agglutinin and immunohistochemistry using SMI-32 antibody. RESULTS: Twenty-two architectonic areas in the Cebus PfC were distinguished: areas 8v, 8d, 9d, 12l, 45, 46v, 46d, 46vr and 46dr in the lateral PfC; areas 11l, 11m, 12o, 13l, 13m, 13i, 14r and 14c in the orbitofrontal cortex, with areas 14r and 14c occupying the ventromedial corner; areas 32r, 32c, 25 and 9m in the medial PfC, and area 10 in the frontal pole. This number is significantly higher than the four cytoarchitectonic areas previously recognized in the same species. However, the number and distribution of these areas in Cebus were to a large extent similar to those described in Old World monkeys PfC in more recent studies. CONCLUSIONS: The present parcellation of the Cebus PfC considerably modifies the scheme initially proposed for this species but is in line with previous studies on Old World monkeys. Thus, it was observed that the remarkable anatomical similarity between the brains of genera Macaca and Cebus may extend to architectonic aspects. Since monkeys of both genera evolved independently over a long period of time facing different environmental pressures, the similarities in the architectonic maps of PfC in both genera are issues of interest. However, additional data about the connectivity and function of the Cebus PfC are necessary to evaluate the possibility of potential homologies or parallelisms.