The most popular myth about the brain is that we “use only 10% of the brain” or: “we use only 10% of the brain” or something similar. Sometimes the percentage changes. The idea is similar.
The brain is made up of about 86 billion neurons, among other things. We are talking about an adult person. Children have about 120 billion of them and lose them during adolescence. However, neurons are only 10% of the cerebral cortex. The majority of the neurons are glial cells.
BRAIN DAMAGE
Almost every brain injury results in impairment of brain function. It is also possible to temporarily produce this effect by affecting specific areas of the cerebral cortex. If we used only 10% of the brain, this effect would not be noticeable. Most of the damage would not give visible symptoms. Often as a result of brain damage, there is a total or partial loss of the ability to perform specific activities – speech, writing, hand movement. Fortunately, it happens that other areas of the brain compensate for the loss.
You probably know how severe changes occur when – as it seems – the oxygen supply to the brain is temporarily cut off.
NEURODEGENERATIVE DISEASES
There are a number of neurodegenerative diseases that cause neuronal loss. Parkinson’s disease, Alzheimer’s disease are more well-known examples. If only 10% of the brain were actually used, most neurons would die. Basically, an older person with this disease would have to use even less than the mythical 10%. It is difficult for him to be able to do anything.
ADOLESCENCE
Children have around 120 billion neurons and have 86 billion remaining by adulthood. Basically, those that are not used disappear. Part of this (apart from the effect of “hardening” of myelin sheaths in neurons in adulthood) is related to the easier acquisition of certain skills at an earlier age. If unused neurons disappear, and we would use 10% of the brain, which is probably only 10% of the neurons, the rest would die. There would not be as many as 86 billion left.
NEUROIMAGING THE BRAIN
Studies using functional magnetic resonance imaging (fMRI), positron emission computed tomography (PET), or electroencephalography (EEG) confirm that for 24 hours, 7 days a week, the brain remains fully active. Even when you sleep, the brain works. Only that it is in different phases of sleep in different cycles of bioelectric activity. A graphic representation of brain activity does not show which regions of the brain are working, but which are working more intensively. We see, for example, how the activity in the speech center increases while speaking.
EVOLUTION
There is no evolutionary justification for such a large brain (about 1.5 kilograms) if we only need 10% of it. Representing 2% of the total body weight, an adult’s brain covers 20-30% of glucose production, children 50%, and infants 60%. If you hear that you can use more, ask where to get the energy for it. For example, the brains of dogs and rodents use only about 5% of the total energy requirement.
EINSTEIN HAD NO BIGGER BRAIN
Also, don’t believe it when someone tells you that Einstein’s genius is in using most parts of the brain than other people. First of all, his brain was smaller than average, and secondly, it is not quantity that matters, but quality. In the population, the distribution of intelligence represents a normal distribution. We can consider 2 % of the population as outstanding individuals in this respect. The same is true at the other end, where we have a similar percentage of people with the lowest IQ. Besides, homo sapiens cannot boast the largest brain. We are outnumbered by elephants (5 kg), whales (9 kg), and even slightly dolphins (1.6 kg). The advantage is the dense packaging of 86 billion neurons. However, it seems that people dominate in terms of cognitive functions, or at least those that have allowed other species to dominate.
YOU DON’T REALLY WANT THIS
Anyway, it doesn’t seem that someone – knowing the consequences – would want his or her brain to work as intensively as the speech center while speaking. First of all, a person would go crazy, because it would be a real Matrix only without Keano Reeves. Imagine that a cosmonaut’s brain in a state of weightlessness could be congested causing a chase of thoughts. Secondly, it would require an extremely high energy expenditure, which with the knowledge that the brain, which accounts for about 2% of body weight, consumes as much as 20-30% of energy, seems even impossible.
GENESIS
The main catalyst for the spread of this myth was the lack of knowledge about the functions of massive frontal lobes or parietal lobe. Now we know that even if their damage does not cause e.g. loss of motor functions, it will mainly affect the ability to think logically and abstractly, make decisions, or plan.
SWINDLERS, NEUROLIFEHACKS
The myth is sometimes used by swindlers who offer to reveal mysterious methods to hack and increase the potential of your brain. Do not let yourself be stretched. When you read this entry, the F-16 will fly over your head, your neighbor will turn on the vacuum cleaner and your neighbor’s child will demand attention, whether you want it or not, you will be distracted. You can’t do everything at once. The energy resources of the brain are limited.