[In Depth] How the body learns to hurt
After 50 years, the neuroscience of pain has a new player. In 1966, researchers traced how the brain learns from repeated stimulation. They found that triggering neurons in one part of the hippocampus—a sliver of brain tissue key to memory—can make linked, distant neurons more likely to fire for many hours afterward, a phenomenon now known as long-term potentiation (LTP). LTP leaves its mark by strengthening some connections between synapses–the connections between brain cells—and not others. Now, researchers have found a new type of LTP that may explain how pain itself "teaches" the brain. The pain-related LTP is driven not by neuronal activity, but by glia—nonneuronal cells that protect neurons from injury, among other duties. Author: Emily Underwood