ABSTRACT
The organization of the prefrontal cortex can hold important clues to understanding its functioning. The Cebus apella present cerebral particularities and behavioral and cognitive flexibility, possessing abilities that demonstrate an overlap with those of big primates. Objectives: To provide evidence of correlations between anatomical particularities of the brain areas analyzed and some cognitive abilities previously described in these simians. Methods: The relative size of the cerebral hemispheres and prefrontal areas (PFA) were measured using a Universal caliper, in 24 hemispheres of C. apella fixed with 10% formaldehyde and kept in 70% alcoholic solution. Results: Data gathered allowed the calculation of the approximate volume (cm3) of the areas under study: right antimere 35.2 cm3 (±5.3), left antimere 31.3 cm3 (±5.4) and of the left PFA 6.0 cm3 (±1.5) and right PFA 6.9 cm3 (±1.7). Conclusions: We concluded that the PFA represents about 20% of the cerebral volume of this primate. No significant differences were found in the antimeres in terms of volume and area of the hemispheres and likewise for the PFA. These animals have a proportionally bigger brain than that of other neotropical primates in the literature. This allows us to infer that the frontal lobe of C. apella is also larger; possibly related to its maturity and developed cognitive functions indicative of the culture transfers characteristic of this species.
A organização do córtex pré-frontal pode conter dados importantes para a compreensão de seu funcionamento. Os Cebus apella apresentam particularidades cerebrais e flexibilidade comportamental e cognitiva, possuindo habilidades que demonstram destacada sobreposição sobre grandes primatas. Objetivos: Fornecer subsídios para realização de correlações entre particularidades anatômicas das regiões encefálicas analisadas e algumas habilidades cognitivas já descritas nestes símios. Métodos: Analisamos o tamanho relativo dos hemisférios cerebrais e da região pré-frontal (RPF), utilizando paquímetro universal, em 24 hemisférios cerebrais de C. apella fixados em formol a 10% e conservados em solução alcoólica a 70%. Resultados: Os dados obtidos permitiram-nos calcular o volume (cm3) aproximado das áreas estudadas: antímero direito 35,2 cm3 (±5,3), antímero esquerdo 31,3 cm3 (±5,4) e das RPF esquerda 6,0 cm3 (±1,5) e a direita 6,9 cm3 (±1,7). Conclusões: Concluímos que a RPF representa aproximadamente 20% do volume cerebral deste primata. Não constatamos diferenças significativas nos antímeros em relação aos volumes e às áreas tanto dos hemisférios cerebrais como das RPF. Estes animais apresentaram tamanho cerebral proporcionalmente maior que os demais primatas neotropicais quando comparamos nossos achados com a literatura disponível, permitindo-nos inclusive inferir que há uma grande amplitude do lobo frontal em C. apella; possivelmente relacionada à maturidade e às funções cognitivas elaboradas indicativas de transferência de cultura características deste animal.
Subject(s)
Humans , Cerebral Cortex , Cerebrum , Cognition , Dementia , Frontal LobeABSTRACT
BACKGROUND: We aimed to study the regional cerebral PET activation patterns during memory tests in medial temporal lobe epilepsy (mTLE) patients and to see whether the activation study could lateralize memory dominance. METHODS: Participants included 6 right mTLE patients, 6 left mTLE patients, and 6 controls. Language was dominant in the left hemisphere in all the participants. PETs were performed while presenting a set of 30 line drawings of com-mon objects with 4 second intervals between each drawing. After 30 minutes, PETs were repeated while presenting a set of drawings with half of the obejcts changed. RESULTS: During the encoding, activated areas were dispersed in mTLE in the superior frontal gyrus, the primary sensory cortex, the premotor area, the supramarginal and angular gyri ipsilaterally or contralaterally, in addition to the inferior and middle frontal gyri activated in the controls. During the retrieval, activated areas were localized in the bilateral inferior frontal gyri and the right medial temporal area in the controls, but also in the premotor area, the primary sensory cortex, and the angular gyrus in mTLE. In the encoding and also in the retrieval, the activated fields of the prefrontal areas contralateral to the epileptogenic zone became wider compared to the controls and those ipsilateral to the epileptogenic zone became smaller. CONCLUSIONS: Cortical areas involved in the encoding and retrieval of the episodic memory are dispersed and contralaterally lateralized to the epileptogenic zone. Lateralization is most prominent in the prefrontal areas.