The Power to Change a Mind

What is the difference between the average person and Albert Einstein? If you guessed it was something in his brain, in the traditional sense of the word, you may want to think again. In The Other Brain, R. Douglas Fields suggests that the difference may not lie in nerve cells, but in what were formerly thought of as mere supporting cells for the brain, the brain's cement, or glia. Glia, which is latin for glue, play a much more important role in all aspects of cognitive and nervous function than previously believed, and in this sense Fields describes an ongoing paradigm shift in how we conceive of the brain. Emerging from the other side of this shift, we're given a much more complex, but complete, view of the brain and a new mystery waiting for scientists to unravel.

For those of you not familiar, glia comprise all the cells of the brain that aren't nerves, of which there are many. In fact, there are twice the number of glial cells as there are neurons, yet science has largely overlooked these cells as backstage hands that don't even have a view of the main show.

Fields, chief of the Section on Nervous System Development and Plasticity at the National Institute of Child Health and Human Development and a leading glial researcher, cogently argues that glia are stars in their own right, both literally and figuratively. Astrocytes, a type of glial cell so named for their star-like appearance, can create new connections between neurons that work together as well as breakup connections between neurons that no longer communicate. Such remodeling may play a crucial role in learning and memory formation. This is one of the many tricks up glia's sleeves that scientists are trying to understand.

The strength of this book lies in its novelty. Few books on the market explore the emerging science of glia, and the ones worth reading probably number even less. Fields, clearly a man passionate about his work, is a good navigator of this topic, as he explores the latest research and the lore of glial history with equal verve. He tells of Fridtjof Nansen, a Norwegian explorer who, over a century ago, first hypothesized that glia are at the root of intelligence. Nansen's evidence was that the number of glia roughly increase corresponding to a creature's hierarchical rank in evolution. The lowly amphibian has few, while the human has many. Albert Einstein, we learn at another point in the book, had twice the number of glial cells in certain brain regions compared with the average person.

The glial argument for intelligence is not exactly bullet proof, however. For example, whales have one of the largest percentages of glial cells, but this is supposedly to provide nutrients to their brains during deep sea dives without oxygen. Fields goes on to tell us that although Nansen's career as a neuroscientist was brief, he later went on to win the Nobel Peace Prize for his work helping refugees during World War I. I find these details such as these laudable and interesting in their own right, but I'm not sure they boost Nansen's credibility in discerning the origins of human intelligence.

Fields invokes a glial argument for intelligence again later in the book. He cites a 2005 study by Vincent Schmithorst that found a relationship between intelligence and robustness of white matter in the brain. White matter is the term for glial cells called oligodendrocytes that wrap themselves around neurons and speed the transmission of messages across long distances. Fields introduces the topic by presenting a hypothetical situation where a doctor reassures a parent that her child has normal intelligence as evident from an MRI scan looking at the child's white matter. However, Schmithorst himself acknowledges that the white matter differences corresponded to areas with increased gray matter, the traditional nerve cells we think of in the brain, and "therefore, our findings could be related and secondary to gray matter developmental processes." Hearty white matter may not increase intelligence; it may simply be a side-effect. Fields does not mention this possibility.

Throughout the book, Fields impresses upon us that glial cells are integral to making sense of our brain and cannot be ignored. Indeed, glial cells are at play in nearly all of the functions of the brain, from preparing a female's brain for motherhood during pregnancy to explaining the hearing loss humans suffer after listening to loud music. He enriches the story by letting us know that Eric Clapton and Bono, along with 40% of rock musicians, are hard of hearing and jesting that "the Rock and Roll Hall of Fame could be nicknamed the Hall of Partially Deaf Musicians."

Fields provides the historical context of glial research and characterizes important scientists along the way, painting a vivid and tangible picture of the blossoming flower of science. I am more appreciative of Schwann cells knowing the story of their namesake, Theodore Scwhwann.

As much as a passionate account can enliven a discussion, it can also make it dull if the reader does not share the same passion for the particulars being discussed. Fields often goes into meticulous detail of the precise setup for every discovery, sometimes down to the temperature and size of the room. He explains it well and it is certainly an important part of the scientific process, but poring over the design of each experiment slows the pace of the book. Sometimes I just wanted the punchline: how do glia relate to hearing loss?

By describing the role glia play in a wide-range of abilities, diseases and quirks of the nervous system, Fields makes a strong case for rethinking their place in neuroscience. For me, The Other Brain was like a college elective to fulfill a science requirement. I didn't know what to expect going in, but I had an entertaining professor, the material turned out to be pretty interesting and it left me with a better understanding of the brain. If you're going to take this course, Fields is the person to take it from.