Wednesday, December 5, 2007

Book Review: The Body Has a Mind of Its Own

Body maps are areas of the brain that represent all areas of your body inside and out. Most of us recall the goofy pictures of homunculi, the distorted figures that represent the relative space our body parts occupy in the somatosensory cortex. Because sensory schemata of the hands and face occupy relatively large areas of our cortex, they are overrepresented in the physical map.

In The Body Has a Mind of Its Own mother-son science writing team Sandra and Matthew Blakeslee write about these and other body maps as revealed by cutting edge neuroscience. My first impression on reading was that neuroscience and, by extension, the authors were overselling body maps and their implications. But after reading a few chapters, I was impressed.
While the authors freely admit, "certain details and caveats that a specialist would consider vital have been condensed, glossed over, or shoehorned into metaphors", their ability to summarize the complex and confusing field of neuroscience is admirable. Granted much of the information is highly speculative, but as an introduction to the field of body maps, I found the book highly informative and entertaining. The take home message is that body maps and the brain are far more plastic than most of us are aware of.

Some of the best topics include:

Can sports players improve their "games" by mental means alone?
How do body maps figure into eating disorders?
What causes phantom limbs?
Can you fool your body into regaining body areas lost to strokes?
What are the "yips"?
Why do video game players move their bodies to the action on the screen?
What happens when you have an "out of body" experience?
Can inanimate objects become part of your "body"?

The book contains many interesting anecdotes, such as:

“Carter” was a master chef at a well-known New York restaurant when, in late 1994, a blood clot in his brain almost cost him his livelihood. Rushed to the hospital in time to receive state-of-the-art clot dissolving care, Carter was left with a potentially devastating problem: He could no longer recognize fruits and vegetables. He couldn’t tell a banana from a leek, though he could still tell a bread knife from a butcher knife and a hawk from a handsaw. He could use English fluently, and his senses were all intact. He had no discernible problems naming or thinking about any other categories of object—just fruits and veggies.

It sounds like a career killer for a chef, but Carter managed to get by. You see, his brain's network body maps still knew what to do with each item. There was nothing wrong with the body maps containing his visual-motor templates for how to manipulate objects. And there was nothing wrong with the body maps that storehoused his library of well-practiced motor sequences involved in food prep. He could still peel a carrot, slice a tomato, or dice an onion—but first he had to be told what each thing was. He would simply query the kitchen staff: “Hey, Jane, is this a cucumber?

"Yeah? Thanks.” Chop chop chop.

On the whole, this book is an excellent introduction to a complex and important topic of science. The prose is lively and easy to read, and once I got going, I was able to finish it in a matter of days. The book is intended for a wide audience, and other than the occasional jargony neuroanatomy term, it is accessible to anyone with a high school education. The only notable failure of this book is to make clearer distinctions on the science that is well-established and the science that is pure speculation. I'm no specialist, yet I would have liked to have seen more pointers to primary sources; an appendix containing citations and/or pointers for further reading would have been highly appropriate and useful.

Clay model on display at the Natural History Museum in London.

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