The brain, evolution, and function By Tomás Núñez, ThD

The brain, evolution, and function
By Tomás Núñez, ThD
Since the true importance of the brain was discovered, its study has been
advancing by leaps and bounds. For this article, I will give an updated view of the
knowledge about this organ in terms of function and capabilities.
The modern human brain is the result of relatively rapid and constant evolution
from the first hominids to Homo sapiens.
It has been possible to corroborate that this evolution was favored by other
advances in body parts, among which the opposable (graspable) thumb and bipedalism
stand out.
In ancient times, scientists had digressed on the functions that this organ
developed, but today, through techniques such as computer tomography or
electroencephalography, we can better understand its structure and dynamics. This
detailed study of the nervous system has also allowed us to learn more about its
functional and structural unit: the neuron.
These cells (neurons) have the ability to generate and transmit electrical
impulses to other cells of the same type by secreting neurotransmitters in a contact
called a synapse. Drugs change the chemical balance of synaptic junctions.
The brain develops various activities of a certain complexity: among these
functions, memory, language, speech, praxis, gnosis, and intelligence stand out.
Today, the study of the brain continues to be very active due to the complexity of
the organ, and although we have a broad vision of its role within the organism, we still
have many unknowns to resolve.

The human brain as we know it today has undergone a process of evolution of
2.5 million years since our most primitive ancestor. It is considered that it began to
increase significantly in size in Australopithecus africanus – a possible predecessor of
our genus with a brain volume of approximately 500 cubic centimeters – and it did so at
an estimated rate of 150,000 neurons per generation.
Despite being similar in size to chimpanzees, the brains of these individuals
began to show significantly larger brain volumes. The first members of the genus Homo,
on the other hand, had a median size of 700 square centimeters and evolved gradually
and almost linearly – without any gaps – until reaching the 1,400 cubic centimeters of
today's Homo sapiens.
Throughout our evolution, improvements in the brain and the body have
complemented each other: when one advanced, it drove the improvement of the other
following a positive feedback loop. Thus, standing up was one of humanity's first
transcendental events, and it is proven that this happened before the appearance of
prehensile thumbs, the ability to make tools, or the development of language.