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Previous issue date: 2011-05-02 === Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico === Cortical interneurons are characterized by their distinct morphological, physiological and
biochemical properties, acting as modulators of the excitatory activity by pyramidal
neurons, for example. Various studies have revealed differences in both distribution and
density of this cell group throughout distinct cortical areas in several species. A particular
class of interneuron closely related to cortical modulation is revealed by the
immunohistochemistry for calcium binding proteins calbindin (CB), calretinina (CR) and
parvalbumin (PV). Despite the growing amount of studies focusing on calcium binding
proteins, the prefrontal cortex of primates remains relatively little explored, particularly in
what concerns a better understanding of the organization of the inhibitory circuitry across
its subdivisions. In the present study we characterized the morphology and distribution of
neurons rich in calcium-binding proteins in the medial, orbital and dorsolateral areas of the
prefrontal cortex of the marmoset (Callithrix jacchus). Using both morphometric and
stereological techniques, we found that CR-reactive neurons (mainly double bouquet and
bipolar cells) have a more complex dendritic arborization than CB-reactive (bitufted and
basket cells) and PV-reactive neurons (chandelier cells). The neuronal densities of CR- and
CB-reactive cells are higher in the supragranular layers (II/III) whilst PV-reactive neurons,
conversely, are more concentrated in the infragranular layers (V/VI). CR-reactive neurons
were the predominant group in the three regions evaluated, being most prevalent in
dorsomedial region. Our findings point out to fundamental differences in the inhibitory
circuitry of the different areas of the prefrontal cortex in marmoset === Os interneur?nios do c?rtex cerebral s?o caracterizados por suas diferentes propriedades
morfol?gicas, fisiol?gicas e bioqu?micas, atuando como moduladores da atividade
excitat?ria cortical dos neur?nios piramidais, por exemplo. V?rios estudos revelaram
diferen?as na distribui??o e densidade deste grupo celular ao longo de diferentes ?reas
corticais em diversas esp?cies. Uma classe particular de interneur?nios intimamente
relacionada ? modula??o cortical ? revelada pela imunohistoqu?mica para as prote?nas
ligantes de c?lcio calbindina (CB), calretinina (CR) e parvalbumina (PV). Em que pese a
quantidade crescente de estudos focando nas prote?nas ligantes de c?lcio, o c?rtex pr?frontal
de primatas ainda permanece relativamente pouco explorado, especialmente no que
se refere a um melhor entendimento da organiza??o do circuito inibit?rio ao longo de suas
subdivis?es. No presente estudo caracterizamos a morfologia e a distribui??o desse grupo
neuronal nas regi?es medial, orbital e dorso-lateral do c?rtex pr?-frontal do sagui
(Callithrix jacchus). Utilizando par?metros morfom?tricos e t?cnicas estereol?gicas,
evidenciamos que os neur?nios reativos a CR (especialmente c?lulas em duplo-buqu? e
bipolares) possuem arboriza??o dendr?tica mais complexa quando comparados aos
neur?nios reativos a CB (neur?nios de tufos duplos e c?lulas em cesto) e PV (c?lulas em
candelabro). A densidade dos neur?nios reativos a CB e CR ? mais elevada nas camadas
supragranulares (II/III), enquanto os neur?nios reativos a PV se concentram
predominantemente nas camadas infragranulares (V/VI). Os neur?nios reativos a CR foram
o grupo predominante nas tr?s regi?es avaliadas, sendo mais prevalente na regi?o
dorsolateral. Nossos achados apontam para diferen?as cruciais no circuito inibit?rio ao
longo das diferentes ?reas do c?rtex pr?-frontal do sagui
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