During the Power Hour Reading, I read an excerpt from The Brain That Changes Itself by Norman Doidge, M.D. I found this book quite fascinating, so I took it home and read the whole thing to learn more about brain plasticity. The first chapter, which we read in class, discusses how a woman named Cheryl regains the ability to balance. See more about the first chapter of this book in my previous blog post about it here. Similarly, the rest of the chapters in his novel detail different people and their stories about how their brains managed to adapt to and compensate for various brain injuries. The major claim/thesis that the author, Norman Doidge, makes throughout this book is that the brain can adapt to overcome injuries and take over the jobs of parts of the brain that die or are affected by the injury - a phenomenon known as neuroplasticity.
It’s funny how I’ve been learning so much in AP Biology about how the animals around us have been adapting for millions of years to fit the changing environment and conditions on Earth. It’s interesting to see how this same principle of evolving and changing is evident in our own brains as well. Doidge draws a direct parallel to this when he says, “the brain is a far more open system than we ever imagined, and nature has gone very far to help us perceive and take in the world around us. It has given us a brain that survives in a changing world by changing itself.” In much the same way that organisms evolve to the changing conditions on Earth, our brains change and adapt to the conditions of our body. This quote articulates the principle of neuroplasticity quite perfectly. In addition, Doidge personifies the brain a little bit to reiterate his main point when he says, “We must be learning if we are to feel fully alive, and when life, or love, becomes too predictable and it seems like there is little left to learn, we become restless - a protest, perhaps, of the plastic brain when it can no longer perform its essential task.” This is another great quote that quite beautifully illustrates this principle of elasticity. He compares our human desire to constantly learn to that of the brain. When a part of the brain dies, it stops learning. However, the brain cannot stand to be plastic and so it will retaliate and do what it needs to in order to keep learning. Thus, the brain will get restless and reorganize its neural pathways to try to regain whatever function was lost from a brain injury. A common thread throughout the anecdotes shared in these chapters is that the individuals all “have senses [that they] didn't know [they] have until [they] lose them.” This quote, although seemingly unrelated to the main point of neuroplasticity, really resonated with me. It echoed the same principle that we’ve been taught since we were children that “you never know what you’ve got until you don’t have it anymore.” This is ever more apparent with the brain injury patients that are discussed in this novel - they all take the functions of their brain for granted until something goes wrong and they are forced to reteach their brains to do something. They realize how every sensation and neural pathway is important for them to function and live normally. This just goes to show how we need to appreciate the power of our brains and take care of ourselves. But if and when something does go wrong, we owe it to ourselves to bear grueling therapy to reteach our brains the functions that were lost.
In Chapter 5 (one of my favorite chapters), for example, Doidge discusses how a stroke patient regained the ability to move and speak. As I’ve mentioned before in previous blog posts, reading about this is always very personal and fascinating for me because my grandmother had a stroke 3 years ago and I also did research on this topic this past summer. Michael Bernstein - the patient discussed in this chapter - had a stroke to the same side of the brain that my grandmother did and the stroke initially paralyzed the entire left side of his body. This is because when a person has a stroke, the tissue on the side of the brain that doesn’t get blood permanently dies. Similarly, when my grandmother had her stroke, her speech, the mobility of her left arm, and her ability to walk properly were all affected. Slowly but surely, with physical and occupational therapy, she was able to train other parts of her brain to take over the functions that the right side of her brain was once responsible for. In doing so, she was able to regain the ability to speak without a slur and walk without hobbling even though the right side of her brain never actually recovered. She never regained sensation or the ability to control her left arm and it has become permanently paralyzed, demonstrating how even though the brain is elastic, it’s ability to adapt is not perfect. The chapter also discusses how a man by the name of Edward Taub experimented with monkeys to see how positive reinforcement in what’s he coined “shaping” during the period after a stroke known as “spinal shock” (when the neurons have trouble firing) could make it easier to relearn actions that were lost during the stroke. He concluded that use of the limb that’s been paralyzed made it much easier for the brain to adapt, not slings and disuse.
Chapter 5 in particular did an excellent job of demonstrating how what we’ve been learning in class can be applied to and seen in the real world. This chapter tied together a previous unit from this class with our most recent unit, specifically the Cardiovascular Diseases (Part 2) Vodcast - in which we learned about how strokes occur - with the Brain Division, Specialization, and Adaptation Vodcast - in which we discussed brain plasticity and how the brain can reorganize neural pathways to make up for brain injuries. Bernstein suffered from a stroke, in which (as we learned in the Cardiovascular Diseases Vodcast) a blood clot forms in a blood vessel going to the brain. Thus, that part of the brain died, preventing the neurons in that section of the brain from receiving input and sending output. The neural pathways to that part of the brain had to (as we learned in the Brain Vodcast) reroute themselves to send sensory input to a different part of the brain that would then take over that particular function. Thus, this book really managed to bring together the various topics we’ve learned throughout the year regarding injuries to the brain and how neurons work to send signals to the brain.
Though - as seen from the inability of my grandma to regain the function of her left arm - the brain cannot self-heal every single brain injury for every single person, it most definitely does have plasticity. The plasticity is just limited. If I were to get the opportunity to ask author Norman Doidge two questions about his work I would ask him (1) what factors play a role in those limits - if a person has a healthier lifestyle, does their brain have more potential to reroute the neural pathways when they suffer an injury? What about age - do younger people have greater brain plasticity? Are there ways to modify one’s lifestyle in order to maximize the chances of having your brain self-heal when it gets injured? Also, (2) do genetics play a role in how elastic your brain is? If so, what factors in one’s family history or genetic makeup would make the brain have more plasticity? How could we design experiments or studies to find answers to these two questions?
I especially enjoyed reading the various ideas Doidge presents in this novel regarding Pascual-Leone’s theory that the brain’s anatomy can be changed with one’s imagination and the use of a transcranial magnetic stimulator (TMS) and the chapter about how neuroplasticity can be a curse when it comes to phantom pain from phantom limbs, in particular, because of how mysterious they are. Take the latter for example. Not much is known about phantom limbs but it was exciting to read how neurologists like V.S. Ramachandran have been working to try and see if phantom paralysis and pain can be “unlearned.” Doidge's work is most definitely not just theoretical because evidence of the phenomenon of neuroplasticity is clear and evident in the cases he discusses throughout the book.
This book is very credible and realistic because it is composed of actual stories and anecdotes from the lives of real people.The ideas about neuroplasticity that Doidge discusses in his novel have also been widely discussed by others in the medical world as it may have incredible practical implications for the future of neuroscience and neurosurgery. If we can figure out how to harness the power of the brain to reorganize neural pathways and then create surgeries and procedures modeled after it, we can make it much easier for people with brain injuries to regain functions that the injury ruined. In the future, such procedures could even render physical and occupational therapies useless. Such procedures and advancements in medicine made based on neuroplasticity would greatly benefit individuals in our society that have been handicapped by brain injuries and could soon have even greater applications when it comes to other mental disorders in which certain sections of the brain aren’t functioning properly.
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