The Other Brain: From Dementia to Schizophrenia, How New Discoveries about the Brain Are Revolutionizing Medicine and Science
by R. Douglas Fields.
Simon & Schuster, 2009
Few scientists can boast that they have held Albert Einstein’s brain in their hands, but Marian Diamond, a biologist at the University of California, Berkeley, is one of the lucky ones. In the 1980s she analyzed preserved pieces of Einstein’s cortex and compared them with the same brain regions in other adults. Einstein’s neurons were indistinguishable from those in other brains. The only thing extraordinary about his brain came as a shock: it was a veritable explosion of nonneuronal cells called glia, which scientists had never associated with intellect. Einstein had twice as many glia as is normal—an observation that suggests that they may have been responsible for his genius.
This anecdote is one of many relayed in R. Douglas Fields’s new book The Other Brain, whose title refers to the fact that glia—Latin for “glue,” because scientists had assumed the cells simply held neurons together and nourished them—have historically been an afterthought in scientists’ minds. Now Fields, a neuroscientist and senior investigator at the National Institutes of Health (and a member of Scientific American Mind’s board of advisers), is convinced that a glial revolution is under way. Thanks in part to his own research, glia are now being uncovered as critical players in brain development, learning, memory, aging and diseases, including schizophrenia, epilepsy and Alzheimer’s disease.
According to Fields, glia are like a tortoise to the neuron’s hare: they do not communicate via flashy, linear electrical impulses like nerves do but instead send messages slowly using chemicals that can diffuse broadly throughout the brain, allowing them to influence many regions in complex ways. Fields explains that glia actually control much of what neurons do and, furthermore, that neurons are involved in fewer brain processes than scientists initially thought. “The rapid ‘within an eyeblink’ functions of our nervous system are actually a narrow slice of cognition,” Fields writes. Slower processes—such as emotions, learning and aging—“operate over time scales where glia excel.”
Tackling 300-plus pages about glia may sound like a daunting task, but Fields makes the experience an adventure. The Other Brain reads almost like a mystery: readers start by thinking of glia as witnesses to the various happenings of the brain but then slowly come to realize, through Fields’s colorful anecdotes and descriptions, that they are actually the brain’s primary movers and shakers. Glia have been “hidden in the blind spot of preconceived ideas,” he writes. And now, as scientists learn more about them, “we are glimpsing a far greater universe of brain function than we had ever imagined.”