This book examines the role of the nervous system in movement and bodily activity. It describes how one’s body is able to perform extraordinarily complex maneuvers that we often take for granted because they feel effortless. It investigates some of the ways in which the interface between body and brain go awry, as well as the various effects this can have. It also offers insight into how we can be deceived because we are experiencing the world less directly and more through the shaping activities of the brain than we feel is true.
The book contains ten chapters, plus a little forward and back matter. The first chapter is entitled “the body mandala” and it provides an overview of how the nervous system can be thought of as a series of maps layered upon maps that routes various input from outlying areas to the brain and commands from the brain to the outlying areas. A “mandala” is a symbolic representation of the universe [from Hindu and Buddhist traditions], and this notion is repeatedly revisited throughout the book.
Chapter 2 explores the mapping of the homunculus and its ramifications. If you’ve ever seen a 2-D or 3-D image /model of a human being that has gigantic lips and hands and disproportionately small torso and thighs, you’ve seen said homunculus (as the term is used in neuroscience.) The reason it’s scaled this way is that body part size is reflective of space in the nervous system dedicated to said parts and not their actual size. If you’ve ever seen one of those maps–called cartograms–in which the size of a country reflects a statistic, say, population (thus India, China, and Singapore are much larger than their physical size, but Canada is much smaller than its), you get the drift. This chapter also answers the question everyone wants to ask (and many do) which is “why–if the lips are so large because of their dedicated territory in the brain—are the genitals unexpectedly small in the homunculus?
Chapter 3 describes how body maps can be in conflict and what effect this can have. It talks about why people who lose weight often still feel fat and move in ways that are not reflective of their actual figure. It also gets into anorexia (and the lesser known bigorexia) which reflect mismatches between perceived body image and actual body schema.
Chapter 4 investigates a fascinating phenomenon in which visualization can often result in strength and performance gains. Said gains aren’t on the same scale as among those who actually exercise or practice, but the fact that one can make gains without moving a muscle is certainly intriguing. Of course, the takeaway is that one can get the best of both worlds by augmenting physical conditioning and practice with visualization—one has a more finite number of feasible physical training hours in a day (i.e. there are diminishing returns on physical training at some point.)
Chapter 5 is the first of two chapters that deal with problems related to improper interaction between the nervous system and the body. Here we learn about “the yips” that plague golfers and other occupational dystonias. When one begins practicing any physical activity, the objective is to build up muscle memory so that the movements can be completed purely unconsciously. This works through neuroplasticity—the fact that sequences of neurons that frequently fire together become more strongly linked—but neuroplasticity can have a dark side at the extremes.
Chapter 6 considers the way in which the system of maps can fail such that one fails to recognize one’s own limbs, one recognizes extra ones, or the like. Chapter 7 is about peripersonal space—i.e. the physical bubble of space that one needs to feel comfortable, and which varies both culturally and individually.
Chapter 8 delves into the role that upcoming technology may have in changing how we look at the body-brain connection. Mirror neurons are the subject of the penultimate chapter. You’ve probably heard of these neurons which fire when we see someone else perform an action. Usually there is an inhibitory signal to keep our body from actual mimicry, but sometimes you may find yourself unconsciously mimicking the position or body language of another person when one is engaged in an engrossing conversation. (Yawning contagiousness is a featured example.) Mirror neurons play a role in how we learn so quickly, how we sometimes anticipate the behavior or emotions of others, and deficient activity in these cells has been speculated to be responsible for autism.
Chapter 10 describes the role of the insula in human activities. The insula has been found to be involved in emotion and rewards system by which humans are motivated to engage in a number of bodily activities.
The book has many graphics to clarify technical points, many of these being line drawings of the brain and other physiological structures. There is also a glossary of key scientific terms.
I found this book to be fascinating. It was highly readable despite its technical subject matter, and it described these systems and the research about them in a clear manner. I’d highly recommend it—particularly if one is interested in movement, fitness, and optimal human performance.