Is everyone’s brain the same?

In this brief article we are going to answer the question: ‘’Is everyone’s brain the same?’’ We will discover what it is that makes our brains unique and unrepeatable.

Is everyone’s brain the same?

No, everyone’s brain is not the same. Each person develops the brain differently, according to their genetics and experiences obtained during their life.

For the neurosciences, in the brain, which is the physical, organic structure that sustains the mind; resides everything that a person was, is and can become; what you have experienced, learned, and memorized, your consciousness and your meta-consciousness.

There are also her abilities and her difficulties, what she accepts and what it rejects, what it loves and how she loves, what it remembers and what it thinks she has forgotten.

This clearly depends on that, although all humans come into the world with an extraordinary launching pad. Its development will depend on what each one perceives, experiences and processes throughout his life, since at the moment of birth – with the exception of what is inscribed in the genes – for the neurosciences all brains are biologically programmed to perform the same functions.

What will differentiate the brain of one person in relation to that of another is the intricate structure of neural networks that will be formed as these cells communicate with each other as a result of the stimuli they receive from the environment.

This phenomenon, the neurosciences calls it neuroplasticity, and refers to a natural property by which the brain modifies itself minute by minute, second by second.

For this reason, the brain of a biologist is different from that of an engineer, that of a conservative to that of a liberal, that of an atheist differs from that of a religious and that of a taxi driver has areas with different development compared to that of a musician.

Factors influencing brain development

The brain forms during embryonic development, as a thickening located at the end of a tube, the neural tube. Initially, it is nothing more than a large balloon filled with liquid, but little by little, layer by layer, the cells that give it such special characteristics, the neurons, are structured.

This whole process is guided by specific genes, which shape the complex fabric of this organ. Therefore, from the outset, as with our factions, we inherit the genes that direct their basic construction and functional characteristics, which will translate into specific aspects of behavior.

However, the basic word must be qualified, because the plasticity of the human brain is enormous and also depends on complex interactions with the environment.

Genetics

To begin with, although we all have the same genes, these can present alternative forms, gene variants that influence the construction of the brain and its functioning in different ways. It is the same that happens, for example, with hair color. We all have genes that determine that hair has color, but there are people who are blondes, redheads, brown…

On the other hand, each individual neuron can be connected to thousands of other neurons, a process that generates neural networks in whose activation our mental life resides. To communicate, neurons use a biochemical language, based on the secretion of neurotransmitters and their reception by other neurons.

Both neuronal receptors and the enzymes that control the production of neurotransmitters are genetically encoded, and they also have gene variants. To cite some of the many known examples, we know that serotonin, one of the various neurotransmitters produced by our neurons, acts on mood and anxiety.

In general, people whose brain produces a lot of serotonin or whose neuronal receptors are very sensitive to it tend to have a calm and optimistic character, while people with low levels are more prone to anxiety and depression. Genes are also known whose different variants predispose to a greater or lesser extent the development of artistic, numerical, or verbal creativity.

The mind, between genes and the environment

But it is not that simple, since not everything depends on these neurotransmitters and their receptors, but also on neuronal connections. And many of them not only do not follow a pre-established pattern, but can also change during an individual’s life.

When the brain is formed, from the fetal stage and up to adolescence, neurons genetically predisposed to establish connections emit exploratory processes. If they find an active neuron and the connection is beneficial for brain function, it is maintained.

Otherwise, return. And this depends, to a large extent, on environmental stimuli, on the experiences of each one, which in this way contribute to shaping the brain.

Also, if a certain connection is activated often, it tends to be reinforced by parallel connections. This plasticity is much more pronounced before birth and during childhood, but it is maintained throughout life, which explains that in many cases the loss of mental abilities due to brain injuries can be compensated by other neurons.

Therefore, the neural structure not only is, it is made and remade. And from this relatively plastic structure our mental life is born, and with it our behavior patterns.

Finally, the environment also regulates the level of functioning of, at least, some of these genes, introducing, still not very well known, what are called epigenetic modifications.

These consist of the addition of certain molecules in the genetic material, which regulate their functioning, activating or inhibiting the activity of certain genes, without altering the message they encode.

They would be like traffic signs on a highway, regulating the speed and the passage of vehicles without altering the route. For example, the presence of one of these modifications in a specific neuronal receptor has been related to negative experiences during childhood, which increases the predisposition to commit suicide.

All these reasons mean that there are not, nor can there be, two exactly alike brains, not even in twins, which implies that there are not two identical minds. Therefore, when we talk about the influence of genes on our behavior, we always talk about predisposition, not absolute determinism.

How does diversity arise in the connections and functions of the brain?

The genetic variability that we inherit from our parents plays an important role. However, even identical twins raised by the same parents can differ markedly in their mental functioning, behavior, and risk of mental or neurodegenerative illness.

In fact, mice bred to be genetically identical and treated in the same way in the laboratory show differences in their ability to learn, in the way they overcome fears and in their responses to stress, even though they are the same age, the same sex and have received the same care. Surely some other process must be intervening.

Certainly, the experiences we acquire in life also matter; they can, for example, affect the strength of connections between certain sets of neurons. But there is increasing evidence that other factors are at play, such as processes that mutate genes or that modify the behavior of a gene, both during the early stages of embryo development and later in life.

These phenomena include alternative splicing, in which a single gene gives rise to two or more different proteins. Proteins do most of the cell’s chores. Therefore, the type of proteins that it synthesizes will affect the functioning of the tissue to which it belongs.

The role of epigenetic changes, DNA modifications that alter gene activity (by increasing or decreasing the synthesis of certain proteins) without changing the information in the genes, is also being investigated.

Fingerprints

Fingerprints, the retina, the iris, the geometry of the palm of the hand or the voice allow the unequivocal recognition of people. But, would it be possible to identify an individual based on the anatomical characteristics of his brain?

Like fingerprints, the anatomy of each human brain is unique, research from the University of Zurich published in Scientific Reports has discovered. This individual characteristic of the brain is the result of each person’s genetic characteristics combined with their life experience, according to the researchers.

It was already known that each person’s experience leaves a mark on the brain, something that has been observed in professional musicians, chess players or golf players: they have particular characteristics in the brain regions that they use the most for their specialized activity.

However, events of shorter duration can also change patterns in the brain: if, for example, the right foot is held still for two weeks, the thickness of the cerebral cortex in the areas responsible for controlling the immobilized foot is reduced.

“We suspect that those experiences that have an effect on the brain interact with genetic makeup so that, over the years, each person develops a completely individual brain anatomy,” explains lead author Lutz Jäncke in a statement.

200 brains analyzed

During their research, Jäncke and her research team examined the brains of nearly 200 healthy older people using magnetic resonance imaging three times over a two-year period. In total, the brains of 191 people between the ages of 64 and 81 were analyzed.

More than 450 brain anatomical features were evaluated, including very general ones such as total brain volume, cortex thickness, and gray and white matter volumes.

The cerebral cortex is the outermost layer of the brain that covers the irregular surface of the cerebral hemispheres.

60% of the brain is made up of white matter, which is what transmits information from different parts of the body to the cerebral cortex. Gray matter occupies 40% of the brain and is found in regions involved in muscle control and sensory perception.

Subsequent analysis revealed that simple measures such as the thickness, surface area or volume of the cerebral cortex are sufficient to discriminate one subject from another. Surprisingly, the volume and total surface of the brain, even more general parameters, were also specific to each individual.

“With our study we were able to confirm that the structure of the brain of people is very individual”, explains Jänckes. “The combination of genetic and non-genetic influences clearly affects not only the functioning of the brain, but also its anatomy.”

That means that the analysis of a person’s brain allows us to know not only their life trajectory, but also their identity, since no two brains are alike in human anatomy.

These data suggest that the human brain has a highly “personalized” architecture, determined by the action of specific genes, environmental factors, and experiences. 

Likewise, the finding shows the existence of a kind of “brain fingerprint” that could complement the use of other biometric measures, in order to verify the identity of a specific subject.

That does not mean, however, that the unique identity of each brain can be commonly used, as is done with fingerprints, to recognize the authorship of a person.

The authors recognized that one of the limitations of the research was the limited number of evaluations performed on the participants. Despite this, the team has plans to continue studying its volunteer population for the next two to three years, and they will use their findings to validate existing results.

Now, you know, you are completely unique.

FAQS: Is everyone’s brain the same?

References

Kolb, B. (2018). Overview of Factors Influencing Brain Development. The Neurobiology of Brain and Behavioral Development, 51–79. https://doi.org/10.1016/b978-0-12-804036-2.00003-0

‌Every person has a unique brain anatomy. (2018). Retrieved October 20, 2020, from ScienceDaily website: https://www.sciencedaily.com/releases/2018/07/180710104631.htm#:~:text=Like%20with%20fingerprints%2C%20no%20two,University%20of%20Zurich%20has%20shown.

Our brains are made of the same stuff, despite DNA differences. (2015, September 18). Retrieved October 20, 2020, from National Institutes of Health (NIH) website: https://www.nih.gov/news-events/news-releases/our-brains-are-made-same-stuff-despite-dna-differences

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