The Body: A Guide for Occupants

by Bill Bryson

The nucleus accumbens, a region of the forebrain associated with pleasure, grows to its largest size in one’s teenage years. At the same time, the body produces more dopamine, the neurotransmitter that conveys pleasure, than it ever will again. That is why the sensations you feel as a teenager are more intense than at any other time of life. But it also means that seeking pleasure is an occupational hazard for teenagers. The leading cause of deaths among teenagers is accidents—and the leading cause of accidents is simply being with other teenagers. When more than one teenager is in a car, for instance, the risk of an accident multiplies by 400 percent. Everybody has heard of neurons, but not so many are familiar with the other main brain cells, glia or glial cells, which is a little odd because they outnumber neurons by ten to one. Glia (the word means “glue” or “putty”) are the cells that support neurons in the brain and central nervous system. For a long time,