Scientists have discovered a brain signal that, like an encouraging bystander at a marathon, urges us keep working at a task in order to receive a reward.

If these signals are overly active, they might contribute to obsessive-compulsive disorder or drug abuse, according to the study authors. Their research appears in the journal, Science, published by the American Association for the Advancement of Science (AAAS).

"Research over the last decade has shown that addiction is a brain disease--it comes about because drug use distorts the brain's functioning. This research is an important new lead in efforts to understand just how brain changes get translated into the compulsion that characterizes addiction, " said Alan I. Leshner, Chief Executive Office of AAAS, and formerly Director of the National Institute on Drug Abuse.

Science author Munetaka Shidara, of the National Institute of Advanced Industrial Science and Technology, in Ibaraki, Japan, noted that the signal may be part of the biological basis of motivation.

Understanding how this signal works normally, as well as when its activity is abnormally high or low, may shed light on why individuals seem to have different levels of motivation for performing similar tasks," said Shidara.

The signal seems to wind down just before a reward is reached. Understanding that the reward is a sure thing may be more important than actually receiving it, said Barry J. Richmond of the National Institute of Mental Health in the United States.

Imagine youre in a tall building, waiting for the elevator, but it doesnt come. Your anxiety increases, but then you hear a bell ding on the next floor, and you feel better, because youre sure whats going to happen next. The signal we saw is like that, Richmond said.

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Contact: Lisa Onaga
lonaga@aaas.org
202-326-7088
American Association for the Advancement of Science
30-May-2002