Neural Plasticity: “Change Your Brain” part 2
Continuing with my overview of Sharon Begley’s book Train Your Mind Change Your Brain, I’d like to proceed toward a discussion about the human implications of neuroplasticity research. In the last post, we left off with the realization that the human brain is a malleable system whose functionality is patently not fixed by genetic predeterminsim: regions such as the visual cortex which would normally process visual information are commandeered, for example, by the tactile sensations in blind Braille readers in order to create enhanced sensitivity in discrimination of fine touch.
As the paradigm of the non-deterministic human brain began to emerge, a major question that naturally came to the fore is whether or not an adult brain—one that has already gone through its most dramatic periods of development—could or could not manifest significant physical change based upon experience. Two sets of experiments serve as clear illustrations to the affirmative. In a PNAS-published study comparing the brains of London cab drivers to non-cab driving control subjects, it was demonstrated using structural MRI that the hippocampal brain regions—involved in spatial memory and orientation—were significantly enlarged in the cab-driver population, giving weight to the idea that the cab-drivers’ brain had actually physically adapted to better suit them for the demands of their occupation.
A second study with similar conclusions involved the sensorimotor regions of the adult brain. A group of adult subjects was given the opportunity to learn to play the violin for a period of several weeks. Following their foray into violin-playing, the brain regions in the sensorimotor cortex connected to the four fingers of the left hand that actively finger the violin strings had expanded their “real estate” in the brain. Or in other words, the increased use of the four fingers most active in violin playing caused a clear enlargement in the brain regions that communicate with these fingers. Taken in concert, the London cabbies and the beginner adult violinists play to the same tune: namely, the perspective that in both the cognitive and the sensorimotor domains, even the adult brain can rewire to better accommodate the experiences that it undergoes. It cannot be overemphasized how dramatically this conclusion breaks from decades of established neuroscience dogma, i.e., that once the human brain develops it is an organ that is fixed and unchanging.
In the next post, I will wrap up the summary of Train Your Mind Change Your Brain, and segue into open-ended questions about human nature, and the implications of neuroplasticity in a collective effort to create a more positive social context.
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