This complex and mysterious organ fascinates us. Thanks to the new medical imaging devices, functional MRI in particular, it has revealed itself a little more in recent years. Here are 5 of its amazing facets!
1. Malleable at will
It has long been thought that the brain is an immutable, static organ. We now know that by creating, undoing or reorganizing neural networks, it adapts according to our experiences.
It is largely this mechanism that allows us to learn and memorize throughout our lives: while information takes the form of a network of neurons, its connections can be strengthened after a number of repetitions. This “neuroplasticity” also allows the brain to recover and, in some cases, restructure itself as a result of a disorder or injury.
2. Grows by removing connections
This is one of the mechanisms of neuroplasticity: when a connection is ineffective or unused, it is removed. For the brain to develop normally, removing connections is as important as creating them.
The brain knows two stages during which its connections multiply massively: one during childhood and the second, during adolescence. These stages are followed by “big housekeeping,” where the connections that are no longer used are eliminated, which protects the brain from the assault of an excess of signals. In short, for the brain to develop normally, removing connections is as important as creating them.
3. Mixed senses: the fault of the neurons?
Have you always and unintentionally associated a letter with a specific color or smell? You could be part of the 1% of the population “affected” of synesthesia, the neurological (but not pathological) condition that makes a person perceive a – more rarely two – additional sensation in an area of the body other than the one receiving the stimulus.
Since we normally have 5 senses and a minimum of 10 combinations of senses are possible, this equates to 20 potential base combinations. Since it is now known that children are “synaesthetized” until about two years old, and in their development, the brain eliminates superfluous connections, researchers suggest that synesthesia could come from connections that should have been destroyed early in life and have persisted. The “synesthetes” could have a better memory but could be a little less skillful at the motor level.
4. Adolescence: major remodeling
In adolescence, the brain lives a major and fast remodeling in both its structure and its operation. Its nerve transmissions are multiplied, its connections are reinforced, and it becomes globally more complex and efficient.
However, the adolescent’s brain is only 80% developed, and it is only when it’s around 25 or even 30 years old that it reaches maturity. The remaining 20% concerns the prefrontal cortex, this area associated with the control of our behaviors, from which reasoning, judgment, planning, and deduction emanate. Very malleable, this adolescent evolving brain reacts with intensity, is quicker to take risks, but it also has a great capacity for learning!
5. No new neurons in adulthood?
This was the conclusion of a recent study from the University of California, San Francisco (UCSF). The opposite has been the case since the 1960s, particularly because of the birth of new neurons (neurogenesis) in adult animals, including rats. At the turn of the 2000s research reported the presence of neurogenesis in humans, and in 2013 another study estimated that in adults 700 new neurons emerged each day.
With the latest development in research, however, it will be necessary to revisit these assumptions once again.
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