US, WASHINGTON (ORDO NEWS) — The cerebral cortex provides perception, thinking, speech and many other functions. To the surprise of scientists, it turned out that a developed prototype of this area of the brain, which actually makes us rational, existed more than half a billion years ago in the common ancestor of man and lamprey.
The discovery is described in a scientific article published in the journal Nature Ecology & Evolution.
The development of the cerebral cortex has become an evolutionary trump card in the sleeve of mammals and especially humans. In our species, the cortex occupies 80% of the brain volume. It is here that the main functions that actually make us people are localized: thinking, speech and so on.
Other animals also have a brain region similar to the human cerebral cortex. Depending on the particular species, it is usually called the cortex, mantle or cloak of the brain, combining all these terms with the general name “pallium”.
In all mammals, reptiles and birds in pallium, information from all sensory organs is processed, movement control is carried out, conditioned reflexes are formed. Having concentrated all these most important functions in himself, he became a kind of “brain of the brain.”
It is believed that in other vertebrates, pallium is responsible primarily or even exclusively for the sense of smell. This means that the “elevation of pallium” occurred only in amniotes.
Recall that amniotes are a treasure (a group united by a common ancestor) of vertebrates in which germ shells form . Of modern animals, it includes mammals, birds and reptiles. The last common ancestor of all amniotes lived about 250 million years ago.
However, a new study calls into question the monopoly of this group on developed pallium. Having studied the lamprey brain, which does not belong to amniotes, neuroscientists found a lot of curiosity.
So, researchers found pallium zones responsible for processing visual information and signals from other senses. An area responsible for motion control was also discovered.
It is worth remembering that the last common ancestor of lampreys and amniotic lived about 560 million years ago.
“This shows that the birth of the cortex should be carried over 300 million years ago,” summarizes the head of the research team, Sten Grillner of the Karolinska Institute in Sweden.
“This, in turn, means that the overall structure of the human brain has developed over 500 million years ago, that is, before the lampreys separated from the evolutionary line that led to mammals and humans.”
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