Neuroplasticity, which is the brain’s ability to adapt and change, has always aroused the interest of the scientific community and the general public. Some truly extraordinary stories have helped shape the idea that the brain unleashes untapped potential and reorganizes itself to acquire new skills when faced with challenges. However, further analysis calls into question this dramatic depiction of neuroplasticity.
Really exceptional cases?
Our brains are adaptable, as demonstrated, for example, by reports of blind people developing extraordinary echolocation skills so that they can navigate complex spaces using only their sense of hearing.
Some stroke survivors also report stories of miraculous motor recovery.
Our brains also appear to show some ability to reorganize after physical insults, including changes in the brain’s representation of limbs after amputation or alterations in sensory maps after injuries.
These stories are often interpreted as examples of the brain’s amazing neuroplasticity, but are we actually able to tap into unused brain potential reserves after injury or have these captivating stories led to a misunderstanding of the brain’s true plastic nature?
A careful review of classic studies on brain reorganization after neurological problems suggests that the brain rather than creates new functions Improve or modify its current structure. In other words, it appears that these latent abilities have been present from birth and that our brain will use them strategically in response to challenges.
Let’s take a concrete example. In a previous study, researchers observed how the brains of mice responded to injury to a specific part called the “barrel” of the primary sensory cortex.
A controlled hit destroyed one of the shell drums. After this process, the researchers expected that the remaining neighboring cells from the destroyed barrel would be used to resume the function of the damaged part. They then considered that the reorganization might involve a change in the part of the body to which the cell responds, which could occur through the creation of new brain connections.
However, the researchers found that neighboring cells did not develop new connections. Instead, cells that had already adapted to the damaged part were “strengthened,” or strengthened, to compensate for the loss. Hence, this enhancement does not require a fundamental structural change in the brain. It’s more than a Functional modification rather than comprehensive reform.
A few decades ago, Nobel Prize-winning neuroscientists David Hubel and Torsten Wiesel conducted experiments on ocular dominance in kittens. By suturing a cat’s eyelid, they observed changes in the visual cortex. Contrary to expectations, neurons in the visual cortex, initially designated for the closed eye, began to interact more with the open eye. These findings have been interpreted as evidence of the brain’s ability to reorganize its sensory pathways in response to changing sensory experiences early in life.
However, subsequent tests showed that the change in eye control in kittens did not represent the creation of new visual abilities. Alternatively, there could have been a modification of contralateral eye preference within the existing visual cortex. Neurons that initially adapted to the closed eye would not have acquired new visual abilities, but rather would have increased their response to information from the open eye.
Multiple abilities capable of seizing
As part of this news published in eLifeIn this study, researchers examined ten of the most common examples of reorganization in neuroscience, reevaluating published evidence from a new perspective. They say that much of the basic work purported to explain brain reorganization has been misinterpreted over the years.
” In our opinion, the term reorganization, if it deserves the name, implies a “redesign of functional structure”, i.e. a clear change in local processing in an area leading to a new functional role.“We can read in the study.” As such, reorganization assumes that experience can transcend the genetic model of brain function. At the heart of this idea is the idea that the cortex possesses, to varying degrees throughout life, multiple latent capacities that can enable a particular cortical area to perform the new tasks assigned to it.“.
Thus it is ultimately this pluripotency that will allow a particular brain region to “take over” the missing region that it initially filled in due to profound changes in behavioral abilities and needs.