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Brain signal cheers us on, researchers say NEW YORK (Reuters Health) - Scientists have identified a brain signal that serves as our own personal cheerleading squad. In an experiment in monkeys, as the animals came closer and closer to completing a task for which they would be rewarded, the brain signal, generated in a region called the anterior cingulate, increased in intensity. Abnormalities in this signal could contribute to disorders related to motivation, such as obsessive-compulsive disorder (OCD) and drug abuse, according to the study's authors. When participating in an activity, we are constantly comparing our current progress with our expectations of achieving a goal, and our expectation increases the farther along we go toward reaching the goal, according to Dr. Munetaka Shidara of the National Institute of Advanced Industrial Science and Technology in Japan and Dr. Barry J. Richmond of the National Institute of Mental Health in Bethesda, Maryland. This implies that there are signals in the brain that are involved in this expectation, the researchers note in a report in the May 31st issue of the journal Science. The anterior cingulate was a good place to look for such signals, Shidara told Reuters Health, since it has connections to other parts of the brain believed to be involved in reward-seeking behavior. The Japanese researcher added that there is some evidence that the anterior cingulate is abnormal in cases of OCD and drug addiction. In the study, monkeys received a reward after completing a series of tasks. The only way the monkeys knew that they were getting closer to the reward was a set of light cues that became brighter as the monkeys advanced. Shidara and Richmond detected a signal coming from a set of neurons in the anterior cingulate, which increased as the monkeys got closer to the prize. "We found that the anterior cingulate neurons responded more strongly as the reward approached, indicating the signal is related to reward expectancy," Shidara said. The animals also made fewer errors as they came closer to getting their reward. But when the researchers changed the schedules of light cues so the monkeys could not tell how close they were to getting the reward, the signal from the anterior cingulate disappeared, the report indicates. The researchers speculate that the signals from this part of the brain are disturbed in disorders that involve motivation and reward, such as OCD and drug abuse. "We can imagine that abnormally high activity would lead to a constant feeling of expectancy without resolution no matter what action is taken," Shidara said. The findings could lead to new treatments for patients with low motivation, OCD and drug abuse problems, according to the Japanese scientist. Understanding signals like the one produced in the anterior cingulate should help scientists understand more about what controls both normal and abnormal actions in people, according to Dr. Laura L. Peoples of the University of Pennsylvania in Philadelphia. It is possible, Peoples notes in a related editorial, that drug addicts may experience diminished activity in this part of the brain, making it difficult to control their actions in a way that maximizes benefits and minimizes harm. SOURCE: Science 2002;296:1709-1711. Last Updated: 2002-05-30 16:12:15 -0400 (Reuters Health) By Merritt McKinney Copyright 2002 Reuters Limited. http://www.reutershealth.com/archive/2002/05/30/eline/links/20020530elin003. html janet paterson: an akinetic rigid subtype, albeit primarily perky, parky pd: 55/41/37 cd: 55/44/43 tel: 613 256 8340 email: [log in to unmask] smail: 375 Country Street, Almonte, Ontario, Canada, K0A 1A0 a new voice website: http://www.geocities.com/janet313/ ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn