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High note: Music thrills trigger reward chemical

Jan. 10, 2011 - 09:38 By 양승진

People who become euphoric over music unleash dopamine, a brain chemical that also induces the sense of reward that comes from food, psychoactive drugs and money, an unusual study says.

   McGill University researchers in Montreal, Canada, recruited eight volunteers aged 19-24 among 217 people who responded to advertisements requesting people who experienced "chills" -- a marker of extreme pleasure -- when listening to music.

  After careful selection, the volunteers were put into a positron emission tomography (PET) scanner, which is able to spot a tagged chemical, raclopride, that works on dopamine receptors in brain cells.

   They were also wired up to sensors that measured them for heartbeat, respiration, temperature and skin conductance.

   Listening to their favourite piece of spine-tingling music, the volunteers showed a rush of physical activity and also unlocked a release of dopamine in the striatum area of the brain.

   The effect occurred even in anticipation, before the "chill" peak occurred.

   But no such dopamine surge was seen when the volunteers listened to neutral music which, previous tests showed, was known to leave them emotionally cold.

   Seeking to find out more, the scientists then put the volunteers in a frequency magnetic resonance imaging (fMRI) scanner, which highlights flows of blood in the head, thus showing which part of the brain is being activated.

   A part of the striatum known as the caudate was involved during the anticipation phase. But during the peak emotional response, a different striatum area known as the nucleus accumbens was involved.

   The results shed light on the exclusive regard that humans have for music, say the researchers.

   Reward sensation could help explain why music is liked in every society -- but also why appreciation of it is such an individual or cultural thing.

   Scientists consider dopamine to be an ancient chemical that is essential for survival.

   It dishes out feel-good jolts in response for life-supporting actions such as eating and for acquiring "secondary" tangibles such as money. The mechanism can also be triggered by drugs.

   But music is abstract, is not directly essential for survival and is not one of these "secondary" or conditioned sources of reward, says the study.

   "(Abstract) stimuli have persisted through cultures and generations, and are pre-eminent in most people's lives," it says.

   "Notably, the experience of pleasure to these abstract stimuli is highly specific to cultural and personal preferences, which can vary tremendously across individuals."

   One possible explanation for this is because of the emotions invoked by music -- "expectations, delay, tension, resolution, prediction, surprise and anticipation," among others.

   The paper, headed by Valorie Salimpoor and Robert Zatorre, is published online by the specialist journal Nature Neuroscience. (AFP)

<한글뉴스>

좋아하는 음악, 돈 만큼 행복감 준다"<加연구팀>

    자신이 좋아하는 음악을 들으면 행복을 느끼게 하는  신경 전달물질인 도파민이 분비된다는 연구 결과가 나왔다.

    9일(현지시각) 캐나다 몬트리올 맥길대학교 연구팀은 모집광고를 보고 지원한 1 9~24세 성인 가운데 8명을 선정, PET스캐너(양전자방출단층촬영장치) 등을 이용해 이들이 좋아하는 음악을 들을 때의 반응을 살펴봤다.

    그 결과 온몸이 짜릿해질 정도로 좋아하는 음악을 들을 경우  선조체(striatum.

線條體)라는 뇌 부분에서 도파민이 분비되는 등 신체적 반응이 나타나는 것으로  관 찰됐다.

    도파민은 쾌락이나 만족감을 느끼게 하는 신경전달물질로, 단 음식을 먹거나 정 신과 관련된 약을 복용했을 경우, 혹은 돈을 접했을 때 분비된다.

    특히 뇌의 활성화 정도를 알려주는 fMRI(기능성자기공명영상장치)로 관찰한  결 과, 좋아하는 음악을 들을 경우 처음에는 대뇌 미상핵(caudate) 부분이, 기분이  절 정에 이르렀을 때는 대뇌 측좌핵(nucleus accumbens)이 활성화되는 것으로 나타났다 .

    그러나 감정적인 자극을 수반하지 않는 보통 음악을 들었을 때는 도파민이 분비 되지 않는 것으로 나타났다.

    이 같은 실험결과는 음악에 대한 인간만의 독특한 관심과 태도를 설명해준다고 연구팀은 설명했다.

    연구진은 음악과 같은 "추상적 자극제는 동서고금을 막론하고 존재해왔지만, 이 를 통해 얻을 수 있는 즐거움은 문화나 개인적 선호도에 따라 크게 다르다"며 "이 때문에 개인이 얻는 행복감은 사람마다 크게 다를 수 있다"고 말했다.

    이번 연구 결과는 의학전문지 네이처 뉴로사이언스 온라인판에 게재됐다. (연합)