Tuesday, August 24, 2010

CBRII: The Brain that Changes Itself by Norman Doidge.

As a science-loving geek, I was absorbed by this book, especially the first few chapters. Doidge has put forward a remarkable argument in favour of brain ‘plasticity’, even into adulthood.

For some time, science has held the theory that brains are all 'set up' during the first year or so of life, and for the most part, every person's is arranged the same way. You’ve probably seen the cartoons, with the ‘language’ section and the ‘gross movement’ area set out and coloured in like a child learning to keep inside the lines. According to this theory, damage to the brain will essentially kill off whatever function that part of the brain looks after. You have a stroke that damages the ‘hearing’ part of your brain, you’re hearing impaired for the rest of your life. Plasticity advocates, on the other hand, claim that your neurons have a ‘use it or lose it’ policy, and any that are not utilised are ‘repurposed’ for a different use. The mind does ‘map’ functions to specific locations, but, according to Doidge, the regions are fluid, and the borders are blurred.

Doidge begins his book with woman called Cheryl and a researcher called Bach-y-Rita. Cheryl suffered a rare side-effect of the antibiotic gentamycin, the degeneration of the vestibular apparatus, the delicate arrangement of three tiny organs behind the ear that control our sense of balance. Cheryl became a ‘Wobbler’, and so severe were her symptoms that she literally could not stand still and steady. It was worse in darkness – if you turned out the lights, she would immediately fall to the ground.

Bach-y-Rita designed a hat to replace the complex with signals sent to, of all things, the tongue. If Cheryl leant forward while wearing the hat, she'd feel small bubbles at the front of her tongue. If she leant to the left, she’d get bubbles on the left side, and so on. While wearing the hat, Cheryl could jump, dance, and simply stand still. The idea was to eventually replace the bulky hat with something small and discrete, something like an under the tongue version of a hearing aid.

Only something odd happened to Cheryl. She discovered that she retained her balance after the hat was removed. Initially, the residual effect lasted one-third of the time she was wearing the hat. When she wore the hat for 20 minutes, the residual effect expanded to three times the wearing time, and increased with each session. On the day that Doidge witnessed the experiment, twenty minutes with the hat resulted in over three hours of residual effect. Eventually, Cheryl was no longer a Wobbler, and was able to return to work, and much of her old life. The theory was that her damaged vestibular apparatus was still sending warped signals to the brain, effectively overloading it. By providing the brain with a new input for balance, it recalibrated, utilising the few remaining healthy signals, and possibly some ‘underlying’ mechanisms.

How the brain changes itself is filled with stories like this. My personal favourite is the explanation of the phenomenon of phantom limbs. As I said before, the brain maps during development, assigning places according to use and related activities (the area for the thumb, for instance, is next to the nerves that control your index finger, because when grasping an object, these two digits work together). And, of course, it’s ‘use it or lose it’. If somebody loses a limb, the neuronal real estate responsible for that limb is quickly repurposed for use by the areas around it.

With phantom limbs, there’s a kind of crossed signal – the brain nerves are still active, despite the absence of the periphery nerves, which leads to the sensation of the limb still being there, moving, or even itching. Two ways of getting around this were presented.

Firstly, that neuronal repurposing may mean that signals received from the areas that took over the amputated limb’s neuronal space will affect the phantom limb. A man who experienced chronic itching in his phantom limb found that it was relieved by scratching his face (the nerve map placed the face nerves next to the area that used to control his arm).

The second technique was more effective in people who, for various reasons, had their limb restrained for some time before amputation. With these people, a feeling of ‘deadness’ often remains, like a neuronal ghost, and they reported some relief thanks to a bit of smoke and mirrors. Literally. Put the ‘good’ limb in a mirrored box that created the illusion of two healthy limbs, then tell the patient to lay their phantom limb over the reflected image. Moving the good limb could fool the mind into believing the phantom limb was moving, and ‘reset’ the trapped ‘un-moving’ signal.

I’m using a lot of quote marks in this review. Frankly, I could be using a lot more. Although the science-loving geek side of me loved this book, the trained scientist was not so excited. There’s a lot of pseudo-science in this book, especially the later chapters, which tend to dissolve into vague, untested theories and conjecture. It’s as though Doidge has fallen into the trap of, having made believers out of us, going on to make whatever claim springs to mind. I actually cringed when Doidge used a scene from a work of fiction as an example, weakly justifying it with the author’s ‘years spent on college campuses’. There are plenty of legitimate studies on pornography and college-aged men, there’s really no need to reference My name is Charlotte Simmons. Yes , those legitimate studies won’t produce a phrase as evocative as ‘cum-dumpsters’, but that’s what happens when you step away from artistic licence.

Of course, this book was written for the layperson and perhaps those evocative but inaccurate references were included to avoid boring them. Whatever the trained scientist thinks of the ‘proof’, there’s no doubting the breadth of Doidge’s research. He has chapters on everything from learning disabilities to pornography. There’s so much information that I’m not sure it wouldn’t have worked better as two books containing more specific explanations and studies. Then again, according to Doidge, that feeling could simply be due to a lifetime of media influence severely shortening my brain’s ability to maintain attention.

Ultimately, read this book for the fascinating experiments and an insight into just how amazing our brain actually is. Read it because there will be at least one chapter that will apply to you in some way, even if only to confirm that PETA were always underhanded. But while I whole-heartedly recommend this book, I feel compelled to add that outside of the fascination factor, it is, at best, a source of hope and a good reason to try something completely new for the sake of the grey matter, not a Bible for Better Brains.

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