The uniqueness of the human brain: a review / A singularidade do cérebro humano: uma revisão

ABSTRACT The purpose of this review is to highlight the most important aspects of the anatomical and functional uniqueness of the human brain. For this, a comparison is made between our brains and those of our closest ancestors (chimpanzees and bonobos) and human ancestors. During human evolution, several changes occurred in the brain, such as an absolute increase in brain size and number of cortical neurons, in addition to a greater degree of functional lateralization and anatomical asymmetry. Also, the cortical cytoarchitecture became more diversified and there was an increase in the number of intracortical networks and networks extending from the cerebral cortex to subcortical structures, with more neural networks being invested in multisensory and sensory-motor-affective-cognitive integration. These changes permitted more complex, flexible and versatile cognitive abilities and social behavior, such as shared intentionality and symbolic articulated language, which, in turn, made possible the formation of larger social groups and cumulative cultural evolution that are characteristic of our species.

RESUMO Esta revisão se propõe a relatar os aspectos mais importantes da singularidade anatômica e funcional do cérebro humano. Para isso, faz-se uma comparação entre o nosso cérebro e os de nossos parentes evolutivos mais próximos (chimpanzés e bonobos) e os ancestrais humanos. Durante a evolução humana ocorreu aumento absoluto do tamanho do cérebro e do número de neurônios corticais cerebrais, maior grau de lateralização funcional e assimetria anatômica cerebral, citoarquitetura cortical mais diversificada e aumento das redes neurais intracorticais e do córtex cerebral para as estruturas subcorticais acompanhada de mudança em direção ao investimento de redes neurais na integração multissensorial e sensório-motora-afetiva-cognitiva. Essas mudanças possibilitaram capacidades cognitivas e comportamentos sociais complexos, flexíveis e versáteis, destacando-se a intencionalidade compartilhada e a linguagem articulada simbólica, que permitiram a formação de grupos sociais maiores e a evolução cultural cumulativa característica de nossa espécie.

Morphological affinities of Homo naledi with other Plio-Pleistocene hominins: a phenetic approach

ABSTRACT Recent fossil material found in Dinaledi Chamber, South Africa, was initially described as a new species of genus Homo, namely Homo naledi. The original study of this new material has pointed to a close proximity with Homo erectus. More recent investigations have, to some extent, confirmed this assignment. Here we present a phenetic analysis based on dentocranial metric variables through Principal Components Analysis and Cluster Analysis based on these fossils and other Plio-Pleistocene hominins. Our results concur that the Dinaledi fossil hominins pertain to genus Homo. However, in our case, their nearest neighbors are Homo habilis and Australopithecus sediba. We suggest that Homo naledi is in fact a South African version of Homo habilis, and not a new species. This can also be applied to Australopithecus sediba.

El dilema obstétrico / Obstetric dilemma

Resumen: La teoría darwiniana indica que los seres humanos somos producto de la evolución y la selección natural, que ha tomado millones de años para traernos a nuestra situación actual. En el transcurso de ese tiempo el cuerpo de los animales que nos precedieron y del humano mismo cambiaron en varias formas, y una de los cambios más trascendentales fue el paso de la locomoción cuadrúpeda a bípeda. Ese cambio requirió numerosas adaptaciones entre las que están las del esqueleto de la pelvis y las extremidades inferiores, que redujeron el tamaño del anillo pélvico, por lo que si el feto esperara a nacer hasta que su cerebro madurara completamente, su gran cabeza no pasaría por ese anillo. La solución a este problema, que se ha llamado el dilema obstétrico, fue que el nacimiento ocurriera cuando la cabeza del feto aún no es demasiado grande, lo que implica que el cerebro todavía no está completamente maduro; aun así, el feto pasa con dificultades por el canal y el anillo pélvico. Al momento del nacimiento el cerebro del neonato no está completamente desarrollado y tiene que terminar de madurar fuera del útero, lo que toma tomar alrededor de 20 años. Esto puede explicar no solamente el comportamiento desorganizado de los adolescentes en general, sino también el inicio temprano de algunas enfermedades neurológicas cuyas consecuencias no se ven hasta la edad adulta, cuando la maduración del cerebro ha terminado.

Abstract: Darwinian theory indicates that human beings are products of evolution and natural selection, processes that have taken millions of years. During that time animals and humanoids changed in many ways and one of the most remarkable is the transition of a quadrupedal to a bipedal gait. Such a change required numerous adaptations, many of which are in the skeleton and lower limbs, that reduced the diameter of the pelvis in such a way that if the fetus had to wait to be completely developed to be born his large head would not pass through the pelvic channel. This problem is known as the 'obstetrics dilemma' and its solution was to allow the birth of an immature fetus, which implies a long process of extra uterus development. Even so, to be born the fetus has many difficulties to negociate the pelvic channel. At birth the fetus brain is incompletely developed and has to finish developing out of the uterus, a process that takes about 20 years. This delay might explain no only some unpredictable adolescent behaviors, but also the onset of some diseases whose consequences are seen until the adult years, when brain development has finished.

Ácido docosahexaenoico (DHA), un ácido graso esencial a nivel cerebral / Docosahexaenoic acid (DHA), an essential fatty acid at the brain

Docosahexaenoic acid (C22: 6 -3, DHA) is a long-chain polyun-saturated fatty acid of marine origin essential for the formation and function of the nervous system, particularly the brain and the retina of humans. It has been proposed a remarkable role of DHA during the human evolution, mainly on the growth and development of the brain, effect that allowed the emergence of the first cognitive skills that differentiated our specie from other animals. Currently, DHA is considered a critical nutrient during pregnancy and breastfeeding due to it active participation at both, the structural and functional development of the nervous system in early life. DHA and specifically one of its derivatives known as neuroprotectin D-1 (NPD-1), has neuroprotective properties against brain aging, neurodegenerative diseases and injury caused by the damage generated during brain ischemia-reperfusion episodes. This paper reviews and discusses the importance of DHA in the human brain given the importance of this fatty acid in the development of the tissue and as neuroprotective agent. It also includes a critical view about the use of this noble fatty acid in the population.

El ácido docosahexaenoico (C22:6 ω-3, DHA) es un ácido graso poliinsaturado de cadena larga de origen marino fundamental para la formación y funcionalidad del sistema nervioso, especialmente para el cerebro y la retina de los humanos. Es destacable el rol trascendental que se propone tuvo este ácido graso en la evolución humana, principalmente en el crecimiento y desarrollo cerebral, efecto que permitió el surgimiento de las primeras habilidades cognitivas y de inteligencia que diferenciaron a nuestra especie de otros animales. Actualmente se considera al DHA como un nutriente crítico durante el embarazo y la lactancia debido a su activa participación en el desarrollo del sistema nervioso tanto a nivel estructural como funcional en los primeros años de vida. DHA y específicamente uno de sus derivados conocidos como neuroprotectina D-1 (NPD-1), presenta propiedades neuroprotectoras frente al envejecimiento cerebral, algunas enfermedades neurodegenerativas y a la injuria causada por el daño durante episodios de isquemia-reperfusión cerebral. En este trabajo se revisa y discute la relevancia del DHA a nivel cerebral, considerando la importancia de este ácido graso tanto en el desarrollo cerebral como en los efectos neuroprotectores que presenta. Se incluye, además, una visión crítica sobre el consumo de este noble ácido graso en la población.

Where and When Human Viral Epidemics First Emerged.

Aims: This article attempts to date the conditions, terms and places of the first emergence of the main human viral epidemics (HIV, influenza, measles, smallpox). Place and Duration of Study: Department of Evolutionary Immunology Andent, Inc., between May 2002 and July 2012. Methodology: The investigation was based on the integration and consequent sensing of relevant recent achievements of evolutionary branches of immunology, epidemiology and anthropology. The main focus was on the integration of up-to-date achievements of both evolutionary and historic anthropology with the data regarding inter-ethnic differences in hereditary immunity to relevant infections and the traces of the aforementioned epidemics. Results: In contrast to rabies infection the considered epidemics emerged nonsimultaneously between 14,000 and 10,000 years ago on the Eurasian territories. They were introduced into America and Australia as well as Sub-Saharan Africa during the Great Geographical Discoveries and consequent Colonization. Conclusion: After their origin, both the epidemics and the traits of hereditary immunity against them continued to exist among humankind to the present, supported by genetically mitigated heterozygous forms of infections.

Lactam nonanic acid, a new substance from Cleome viscosa with allelopathic.

Cleome viscosa L. (Capparidaceae) is well known for its medicinal properties. Lactam nonanoic acid (LNA) [2-amino-9-(4-oxoazetidin-2-yl)-nonanoic acid; C12H22N2O3, mol. wt. 242] has been isolated and purified from the root exudates of Cleome viscosa. The aqueous solution of this pure compound has been tested on bacteria (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) and fungi (Aspergillus fumigatus, A. niger and A. tamarii). At a dosage of 500 ppm and above, P. aeruginosa and S. aureus were totally inhibited while E. coli remained unaffected. On the other hand, growth of A. niger and A. tamarii was stimulated while there was no effect on A. fumigatus. This pure compound showed concentration-dependent inhibitory activity on rice, gram and mustard seeds.