The primitive brain of early Homo.

The brains of modern humans differ from those of great apes in size, shape, and cortical organization, notably in frontal lobe areas involved in complex cognitive tasks, such as social cognition, tool use, and language. When these differences arose during human evolution is a question of ongoing debate. Here, we show that the brains of early Homo from Africa and Western Asia (Dmanisi) retained a primitive, great ape-like organization of the frontal lobe. By contrast, African Homo younger than 1.5 million years ago, as well as all Southeast Asian Homo erectus, exhibited a more derived, humanlike brain organization. Frontal lobe reorganization, once considered a hallmark of earliest Homo in Africa, thus evolved comparatively late, and long after Homo first dispersed from Africa.

Patterns of Body Mass Index, Percentage Body Fat, and Skinfold Thicknesses in 7- to 18-Year-Old Children and Adolescents from Indonesia.

BACKGROUND: Body mass index (BMI) and skinfold thickness are widely used to evaluate body composition. Information on patterns of skinfold thickness may help to understand changes in body composition during growth. The objectives of this study were to observe patterns of BMI, percentage body fat (%BF), and skinfold thicknesses of Indonesian children and adolescents aged 7-18 years. METHODS: Weight, height, and four skinfold thicknesses were measured in 2104 school children (924 boys, 1,180 girls) aged 7-18 years from Yogyakarta between 2015 and 2018. BMI and ratios between central and peripheral skinfold thicknesses were determined. %BF was predicted using the equation of Slaughter et al. Data were analyzed using analysis variance (ANOVA), independent sample t-test, and partial correlation (SPSS version 20.0). RESULTS: At 7-18 years, boys and girls showed a comparable gain in BMI. The comparable gain in %BF between boys and girls only occurred till age 10 and total skinfolds till age 11 years. While, %BF and skinfold thicknesses were higher in girls at 12-17 years, central to peripheral skinfold ratio were higher in boys. Partial correlation analyses showed that all skinfold thickness parameters and %BF were significantly correlated with BMI (P < 0.001; r = 0.19-0.87). CONCLUSIONS: The gain in BMI and skinfold thickness between the ages of 7 and 18 years occurred in age- and sex-specific patterns. Instead of comparable BMI, girls showed higher means of total skinfold thickness from age 12 years, while boys had higher central to peripheral adiposity ratio.