RESUMO
OBJECTIVE: This study aimed to compare cortex thickness and neuronal cell density in postmortem brain tissue from people with overweight or obesity and normal weight. METHODS: The cortex thickness and neuron density of eight donors with overweight or obesity (mean = 31.6 kg/m2 ; SD = 4.35; n = 8; 6 male) and eight donors with normal weight (mean = 21.8 kg/m2 ; SD = 1.5; n = 8; 5 male) were compared. All participants were Mexican and lived in Mexico City. Randomly selected thickness measures of different cortex areas from the frontal and temporal lobes were analyzed based on high-resolution real-size photographs. A histological analysis of systematic-random fields was used to quantify the number of neurons in postmortem left and right of the first, second, and third gyri of frontal and temporal lobe brain samples. RESULTS: No statistical difference was found in cortical thickness between donors with overweight or obesity and individuals with normal weight. A smaller number of neurons was found among the donors with overweight or obesity than the donors with normal weight at different frontal and temporal areas. CONCLUSIONS: A lower density of neurons is associated with overweight or obesity. The morphological basis for structural brain changes in obesity requires further investigation.
Assuntos
Encéfalo/patologia , Contagem de Células/instrumentação , Lobo Frontal/anormalidades , Obesidade/diagnóstico , Lobo Temporal/anormalidades , Adulto , Autopsia , Contagem de Células/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/patologia , Lobo Temporal/patologiaRESUMO
We report brain electrophysiological responses from 10- to 13-month-old Mexican infants while listening to native and foreign CV-syllable contrasts differing in Voice Onset Time (VOT). All infants showed normal auditory event-related potential (ERP) components. Our analyses showed ERP evidence that Mexican infants are capable of discriminating their native sounds as well as the acoustically salient (aspiration) foreign contrast. The study showed that experience with native language influences VOT perception in Spanish learning infants. The acoustic salience of aspiration is perceived by both Spanish and English learning infants, but exposure provides additional phonetic status to this native-language feature for English learning infants. The effects of early experience and neural commitment as well as the impact of acoustic salience are further discussed.
RESUMO
We report a Principal Component Analysis (PCA) and the scalp distribution of the normalized peak amplitude values for speech-related auditory Event-related Potentials (ERP) P150-250 and N250-550 in 7-, 11-, and 20-month-old American infants learning English and in 10-13-month-old Mexican infants learning Spanish. After assessing the infant auditory ERP P-N complex using PCA, we evaluated the topographic distribution of each of the discriminatory phases to native and non-native CV-syllabic contrasts used in Spanish and English. We found that the first two Principal Components for each contrast type across ages showing a maximization of differences between the P150-250 and the N250-550 waves, explain more than 70% of the variance. The scalp distributions of the P150-250 and N250-550 components also differed, the P150-250 showing a frontal and anterior temporal distribution, and the N250-550 a more posterior distribution. The older infants showed a broader distribution of responses, particularly for the N250-550. There were no differences in the topographies of the components between same-aged Mexican and American infants. We discuss the perceptual/linguistic functions that each component may reflect during development and across the two cultures.