LOS ANGELES (AP) _ A researcher said Tuesday he believes a breakdown of nerve fibers in the brain cause narcolepsy, a sleep disorder that affects 250,000 people in the United States.
The illness stems from the breakdown of nerve fibers called axons in the forebrain, a region active in inducing sleep, and the amygdala, which is responsible for emotion, said Dr. Jerome Siegel, head of neurobiology research at the Sepulveda Veterans Affairs Medical Center in Los Angeles.
Siegel said at the annual meeting of the Society for Neuroscience that he observed degeneration of axons in the forebrain and amygdala of narcoleptic dogs just before they begin to show symptoms.
``This is the first evidence of degeneration in narcolepsy,″ he said.
Siegel also found connections between groups of cells in the amygdala and the brainstem and between the basal forebrain and the brainstem. These may explain why the disorder involves both sleep and motor symptoms.