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Researchers localize brain region that anticipates reward

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  • Ian Pitchford
    Public release date: 3-Aug-2001 amatush@mail.nih.gov 301-443-0469 NIH/National Institute on Alcohol Abuse and Alcoholism http://www.niaaa.nih.gov/ Alcohol
    Message 1 of 1 , Aug 3, 2001
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      Public release date: 3-Aug-2001
      amatush@...
      301-443-0469
      NIH/National Institute on Alcohol Abuse and Alcoholism
      http://www.niaaa.nih.gov/

      Alcohol researchers localize brain region that anticipates reward

      Researchers at the National Institute on Alcohol Abuse and Alcoholism have
      found that anticipation of increasing monetary rewards selectively activates
      the human nucleus accumbens of the ventral striatum. Since this brain region is
      implicated in animal studies of alcohol and drug self-administration, the
      research may help lead to methods for understanding the biological basis of
      alcohol and drug craving in humans.

      Researchers in the laboratory of Daniel Hommer, M.D., measured changes in blood
      oxygen level dependent contrast in a functional magnetic resonance (FMRI)
      scanner in order to track changes in brain activity that occurred while eight
      volunteers participated in a videogame task involving real money. In this
      monetary incentive delay (MID) task, participants saw cues that indicated that
      they might win or lose money, waited for a variable anticipatory delay period,
      then tried to either win or avoid losing money by pressing a button in response
      to a rapidly presented target. The researchers examined the response of the
      nucleus accumbens during anticipation of different amounts of potential rewards
      (i.e., gains of $0.20, $1.00, and $5.00) or punishments (i.e., losses of $0.20,
      $1.00, and $5.00). They found that nucleus accumbens activity increased as
      volunteers anticipated increasing monetary rewards but not punishments. Another
      nearby brain region, the medial caudate, showed increased activity not only
      during anticipation of increasing rewards but also during anticipation of
      increasing punishments.

      After playing the game, volunteers rated their reactions to the various cues.
      Increasing reward cues evoked increasing self-rated happiness as well as
      nucleus accumbens activity. At the $5.00 level, volunteers who were happiest to
      see the reward cue also showed more anticipatory activation in the nucleus
      accumbens. "Our findings provide the first hint that activity in the nucleus
      accumbens may be related to the types of positive feelings that occur when
      people expect natural rewards," said principal investigator Brian Knutson,
      Ph.D. "This is an important step towards demonstrating that the brain circuitry
      underlying positive and negative feelings may not be the same in humans."

      Using a different FMRI task and analytic method, another group of researchers
      at Harvard funded by the National Institute on Drug Abuse recently observed
      activation of the nucleus accumbens and other brain areas as volunteers
      anticipated a single level of monetary gain or loss, as documented in the May
      issue of Neuron. By varying the amount of anticipated reward, the NIAAA
      researchers extended this work to show that the nucleus accumbens responds
      proportionally to increasing rewards but not punishments. In addition, the
      NIAAA study links reward-related feelings to nucleus accumbens function.

      “Today’s report emphasizes the specific importance of the nucleus accumbens in
      the anticipation of reward and adds valuable new information toward
      understanding the role of reward in addiction,” said NIAAA Director Enoch
      Gordis, M.D. “Since craving is a major problem that many alcoholics face on an
      ongoing basis, NIAAA is committed to understanding brain mechanisms related to
      craving and developing interventions that can help alcoholics to withstand the
      urge to drink.”

      In a given year, about 8 million adult Americans meet clinical diagnostic
      criteria for alcohol dependence (alcoholism) and about 6 million meet clinical
      criteria for alcohol abuse. At some time during their lives, 13 percent of
      Americans experience alcoholism and about 6 percent experience alcohol abuse.


      ###
      The study was conducted at the NIAAA Division of Intramural Clinical and
      Biological Research, Laboratory of Clinical Studies, Section of Brain
      Electrophysiology and Imaging and will appear in the August 15 issue of the
      Journal of Neuroscience (Volume 21, RC159, pp. 1-5, 2001). The research report
      is available online at http://www.jneurosci.org/cgi/content/full/20015472 after
      midnight on August 3.

      A description of work underway in the Division of Intramural Clinical and
      Biological Research and additional alcohol research information are available
      at http://www.niaaa.nih.gov For interviews with Dr. Knutson, please telephone
      the NIAAA Press Office (301-443-0469).

      The National Institute on Alcohol Abuse and Alcoholism, a component of the
      National Institutes of Health, U.S. Department of Health and Human Services,
      conducts and supports approximately 90 percent of U.S. research on the causes,
      consequences, prevention and treatment of alcohol abuse, alcoholism, and
      alcohol problems and disseminates research findings to science, practitioner,
      policy making, and general audiences.
      http://www.eurekalert.org/pub_releases/2001-08/nioa-arl073001.php
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