THE OTHER BRAIN

A detailed exploration of a major part of the brain that has been ignored for decades.

In his first book, neuroscientist Fields, the editor of the journal Neuron Glia Biology, emphasizes that for centuries brain researchers have studied nerve cells, whose long, interconnected fibers exchange electric signals to direct our lives. These neurons make up 15 percent of the brain’s cells, the author writes. The remaining 85 percent cling to neurons, enfold them or drift about. Called glial cells, they don’t conduct electricity, so researchers mistakenly assumed that they only perform modest housekeeping duties or serve as filler. “Dismissed as cellular domestic servants,” Fields writes, “glia were neglected for more than a century after they were discovered.” With lucid prose—and a helpful ten-page glossary—the author reveals their vital role. They may not conduct electricity, but they communicate with each other and with neurons. In fact, the holy grail of brain research—understanding learning, memory, adaptation, mental illness and genius—is tied less to the process of neuron firing than to the mechanics of how glial cells influence them. (Einstein’s brain contained an average number of neurons but a great excess of glia.) Wildly multiplying glia produce brain tumors; neurons rarely turn malignant. When glia malfunction, the outcome can be mental illness or retardation. Scientists long believed that brain neurons were not able to regenerate after an injury. It turns out that they try, but glial cells interfere. Researchers are beginning to see results from preventing this process. Fields enthusiastically delivers the history of brain disease and brain research and travels the world interviewing scientists and explaining their findings. He also goes out of his way to trumpet the miracles that could result from this new knowledge.

So far few have emerged, but Fields makes a convincing case that understanding this “other brain” opens the door to dazzling possibilities.