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Wednesday, January 30, 2013

The brain

At previous posts I've always have made reference to the brain and here I´ll intend to describe it grosso modo, in a very humbly way because I think to describe it would need a library with the size of New York City. 

What can I say about it? It weights between 1300 and 1400 grams on average. The volume is estimated at 1375 cm3 approximately, has more or less an area of two square meters, Yes, you read well!, it fits perfectly inside the skull because it is folded in a very peculiar way, to increase the surface area of the cerebral cortex to the maximum,  this is the reason it has so many  creases.

Now, the brain works thanks to approximately 30 billion neurons (nobody has count them, this is only an estimate), each one of which is interconnected with each other by a number of synapses (connections) ranging from several hundred to more than 20,000, forming a structural network that is about 100 times more complex than the global telephone network.

Some neuroscientist describe this super structure explaining that if we put a one millimeter  square on the brain, it would be estimating the position of 100 000 neurons.

It has been calculated that 70% of the amount of neurons (approximately 14 x 1013 neurons) are found in the cerebral cortex, which is the mantle of nervous tissue that covers the surface of the cerebral hemispheres, Dr. David Susuki calls it our think Cap .

The cerebral neocortex (whose literal definition is new brain) is a complete and external coating of the cerebral hemisphere, is composed between 100 billion and 11.5 billion neurons. This represents a connection between neurons around capacity of 10 x 1013 possible synapses in the human brain.The bark surface area is increased by its folding in spins separated by grooves. The thickness of the neocortex varies from 1.5 to 4.5 mm and is organized in units of functional activity known as areas.

The neocortex is characterized by its development in mammals and, particularly, in non-human primates and human, thus the proportion of the volume of the cortex in humans is higher than in other mammals.
One of the major occupations of the neocortex is the sequence of patterns to make auto processes associated invariant forms and storage hierarchies in order to abstract the world in the best way.
Through interactions between regulatory systems and projection fibers, the cerebral cortex has direct influence on planning, intentions, and the voluntary implementation of the movement. Also it relates with the conscious field, language, thinking, memory, emotional function, and in general all those activities distinguished as higher mental functions.

In order to ensure the cognitive success of the human as specie, the newborn possesses a very large brain in proportion to the size of the body (12% more or less) and during the first 3 years of life, children must learn more quickly the action over the environment; However, the brain, and especially the neocortex continue growing very rapidly, and around at six year of age, the child already owns 90% of the brain mass that will have as an adult. However, current studies show that neural connections continue connecting throughout life.

Some anthropological studies explained that our brain has evolved and increased its complexity and informative content over millions of years, this because its structure reflects all the phases by which has passed, so it´s possible to observe how the brain has evolved from the inside outwards, in the more central areas is the oldest part, the brain stem, which directs the biological core functions, including breathing and heart rate, while emotions are governed by the limbic system, which is shared by the development of the rest of the mammals and finally the cerebral cortex moves around what Carl Sagan described once as an uneasy truce between the brains more primitive, since that's where the matter is transformed into consciousness, and is therein where ideas and inspirations are created and where carries out the process of understanding and learning.


Bear, M., Connors, B.W and Paradiso, M.A. (2001) Neuroscience: Exploring the Brain. Baltimore: Lippincott.
Buritica – Ramírez, E. y Pimienta- Jiménez, H. (2007) Corteza frontopolar humana: área 10. Revista Latinoamericana de Psicología. Volumen 39, No 1, 127-142
Dick, U. and Roth, G. (2008) Intelligence evolved. Scientific American mind. Vol. 19. num. 4. 70-77.
Hawkins, J., and Blakesleem, S. (2004) On intelligence. Times Books. USA.

Sakal, T., Matsui, M., Mikami, A., Malkova, L., Hamada, Y., Tomonaga, M., Suzuki, J., Tanaka, M., Miyabe-Nisiwaki, T., Makishima, H., Nakatsukasa, M., and Matsuzawa. T. (2013) developmental patterns of chimpanzee cerebral tissues provide important clues for understanding the remarkable enlargement on the human brain. Proceedings of the Royal Society Biological Science. Disponible en:

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