Does the brain stop growing?

“It is not the strongest or the fastest that survive, but the one that best adapts to change”, had postulated Charles Darwin in The Origin of Species. And the brain had a lot to do with it: a larger size allowed man to evolve and, although he had no claws, no wings, no strength or speed, he was able to survive and ultimately imposed his will on the planet.

In this post we are going to answer the question ‘’Does the brain stop growing?’’ We will discover at what pace the brain grows, at what age and under what circumstances it stops growing. In addition, we will detail how the brain grows at the macroscopic and microscopic level.

Does the brain stop growing?

Yes, the brain stops growing at about 10 years. Although it has been discovered that it is not fully mature until we are over 30 years old.

During the gestation period, brain development has rapid growth that continues into postnatal life for a long time. Thus, it increases in size four times in the preschool stage; However, the main structural changes occur during childhood and adolescence, a period in which it reaches about 90% of the volume it will have in adulthood.

With few exceptions, the head grows towards 10 years of age, at which time a cap will serve us forever. Now, it is necessary to distinguish between the region of the skull that houses the brain and that which corresponds to the face, since they grow at different rates.

In the newborn, the size of the cranial box does not exceed 25% of what it will be in adulthood. By the age of 7 or 8, it will have grown to 95% of its final size and growth ceases in most boys before reaching puberty.

In general, and without taking into account details such as weeks of gestation or sex, after nine months of pregnancy we are born with an average weight of 3,400 g and a height of 50 cm. The average measurement of the head contour is 34 cm while in the adult it is about 56-58 cm.

The cranial perimeter grows more than 20 cm during our development, and it is an indirect measure of brain growth that increases from 350 g of weight in the newborn to 1,350 g at 20 years of age.

The brain never stops growing: neural networks

We are born with millions of neurons but they are poorly communicated with each other. After being born, of course, the number of neurons increases, but above all, what increases is the number of connections between them.

The formation of neural networks is the factor that contributes the most to brain growth after birth and most of them are already well established by 2-3 years of age.

Unlike that of other mammals, human neurodevelopment is very primitive at birth. While the control of vital functions is highly developed, higher brain functions are barely outlined.

From birth, continuous interaction with the environment contributes to the formation of new neural connections that, based on repetitions, will gradually consolidate into stable networks that will allow them to acquire and perfect the skills that will give them autonomy.

In the long process that leads us to adult life, simultaneously but successively, motor, cognitive and emotional abilities will develop.

Now, a team of neurologists from Columbia University (USA) has discovered that the brain does not stop growing, a finding that could help treat degenerative diseases such as Alzheimer’s.

Previously, researchers believed that the brain did not develop any new cells after childhood, making it much more difficult for adults to acquire new skills or learn a foreign language, for example.

More recent studies suggested that if specific areas of the brain were hyperstimulated, new cells could form. However, a new study published in the journal Cell Stem Cell has concluded that thousands of new brain cells or neurons form all the time, even when people are very old.

Synapse

The work suggests that age-associated memory and mental problems are not due to loss of neurons, but rather to failures in the neurons themselves to communicate appropriately with each other.

“We found that older people have a similar ability to generate thousands of new hippocampal neurons from progenitor cells, as younger people do. However, older people had less vascularization (formation of blood vessels) and perhaps less capacity of the new neurons to establish connections “, explains Maura Boldrini, leader of the study.

This advance could help scientists better understand the causes of dementia and how to prevent it from occurring, as the numbers of people with these neurodegenerative disorders continue to increase.

For their experiment, the experts looked at the hippocampus in 28 healthy individuals between the ages of 14 and 79 who had died suddenly. None of them had cognitive impairment or depression, which can affect the development of neurons.

They found that even in the most mature brains neurons were forming up to the time of death. It is the first time that scientists have observed newly created neurons and the state of blood vessels throughout the human hippocampus shortly after death.

“We found similar numbers of intermediate neuronal progenitors and thousands of immature neurons,” the authors concluded.

The caveat in this case was that older people formed fewer new blood vessels within brain structures and possessed a smaller group of progenitor cells, descendants of stem cells that develop into neurons.

According to Boldrini, this brain deterioration in old age could be due to this smaller set of neural stem cells, the decrease in blood vessels and reduced cell-to-cell connectivity in the hippocampus.

“It is possible that ongoing hippocampal neurogenesis supports human-specific cognitive function throughout life and that the declines may be related to compromised cognitive-emotional resilience,” she concludes.

The brain continues to grow into adulthood: On a microscopic level

They show that the brain area responsible for facial recognition increases over time, but not the area that allows us to identify places and landscapes.

We are born with an excess of neural connections. During childhood development, the brain starts a process of pruning the brain in which it slowly sheds them until the structure of the brain becomes relatively stable.

From birth to our death the brain walks in a single direction, from too much tissue to what is just and essential. But new research casts doubt on this established truth for neuroscience. Brain tissue continues to grow (at a microscopic level) in adulthood, at least one area, the one responsible for facial recognition.

This growth favors older people having a better ability to recognize faces than children. However, while the area that helps to recognize other people’s faces increases, the area responsible for recognizing places and landscapes remains stable.

The results from Stanford University are published in the journal “Science” after comparing MRI scans of 22 children and 25 adults. What the images of the brains of living people showed was later confirmed by post-mortem analysis of deceased adults.

This last test showed visible differences in the deepest cellular structure, between the regions in charge of identifying places and faces.

“We really saw the tissue proliferate,” said lead author Jesse Gomez of the research. “We had taken a pessimistic view of the brain, in which tissue is slowly lost as we age, but we have seen the opposite: what is left after pruning in childhood can be used to grow.”

The area of recognition of places does not grow

But why is only the area of facial recognition growing and not that of places? Or why doesn’t it occur at the same time? There is still no clear explanation.

The researchers indicate that changes in myelination, the white fatty substance that surrounds the axons of some neurons, do not appear to be the only explanation for understanding the expansion of a single area of the brain.

The authors propose that it may be caused by an increase in cell bodies, dendritic structures, and the myelin sheath.

The work provides a greater understanding of brain architecture and shows that tissue growth can be measured in vivo, but the research may also have implications for health. It could lead to treatments for a rare condition, called facial blindness, a disorder that robs the ability to recognize faces.

FAQS: Does the brain stop growing?

What age does the brain stop growing in size?

The American pediatrician Jay Giedd has discovered that the human brain is under construction until the end of adolescence, although at this stage the neurons and nerve connections do not grow, but are “pruned” until the reasoning characteristic of age is reached.

Does brain stop developing?

A study from the Institute of Cognitive Neuroscience in London suggests that the brain continues to develop after childhood and puberty and that it is not fully mature until we are over 30 years old, and even after reaching 40.

Can your brain grow bigger?

It doesn’t matter how old you are. A study finds that the elderly have the same number of new neurons as adolescents.

What happens to your brain at 25?

From that age, things begin to change and nothing is ever the same again. Age 25 is the beginning of a brain crisis. Deep changes take place, the stage is changed, the immature brain is left behind and a new path towards decline begins.

At what age will I stop growing?

The development of boys and women is subjected to endocrine control caused by the action of growth hormone. Everything goes through this mechanism. In other words, technically, men stop growing at 18, and women do so at 16. However, their maturation is completed in the next 6 to 8 years.

In this post we answered the question ‘’Does the brain stop growing?’’ We have discovered at what pace the brain grows, at what age and under what circumstances it stops growing. In addition, we have detailed how the brain grows at the macroscopic and microscopic level.

If you have any questions or comments please let us know!

References

University, S. (2017, January 5). Stanford study shows development of face recognition entails brain tissue growth | Stanford News. Retrieved December 2, 2020, from Stanford News website

https://www.facebook.com/verywell. (2020). Do Humans All Have the Same Brain Size? Retrieved December 2, 2020, from Verywell Mind website

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