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October 1, 1997

Researchers Dissect the Tick and Tock of the Human Body's Master Clock

JAMA. 1997;278(13):1049-1051. doi:10.1001/jama.1997.03550130015006

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KNOWLEDGE about the body's biological clock may help both those who can't sleep and those who can't stay awake. It may permit travelers to avoid jet lag, improve workplace productivity, and reduce industrial and traffic mishaps caused by dips in alertness in the early morning hours. Clock research also may enable physicians to improve patient care by adding a new dimension—body time—to clinical decision making. Researchers recently reflected on what they know and where they're going.

A 2-day symposium to mark the 25th anniversary of the discovery that the biological clock resides in a pair of islands of neurons within the hypothalamus, collectively called the suprachiasmatic nucleus (SCN) for its location just above the optic junction, drew 150 scientists and students to Harvard Medical School in August. Some 19 authors of key SCN papers agreed to discuss their work and recent advances in the field—every one of those invited to