즉흥 연주에 빠진 '재즈 피아니스트'의 뇌는 다르다 Study of jazz pianists finds ‘happy’ and ‘sad’ music evoke different neural patterns

美 연구팀 

“외운 곡 연주할 때와 뇌 활성 부위 달라”

Bill Evans: 1929-1980

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케이콘텐츠 편집

    즉흥 연주를 하거나 캐리커처를 그릴 때처럼 창의적인 활동을 할 때 뇌의 어떤 영역이 활성화될까. 이 질문에 힌트가 될 만한 연구 결과가 나왔다. 연주가의 감정에 따라 활성화되는 뇌 부위와 정도가 다르다는 사실이 밝혀진 것이다.

 

찰스 림 샌프란시스코 캘리포니아대(UC샌프란시스코) 의대 교수팀은 즉흥 연주를 하는 재즈 피아니스트의 뇌 영상을 촬영한 결과 연주자의 감정에 따라 뇌의 활성화 정도가 달라진다는 사실을 밝혀내 ‘사이언티픽 리포츠(Scientific Reports)’ 4일 자에 발표했다.

 

림 교수팀은 이전 연구에서 즉흥적으로 연주할 때는 곡을 외워서 연주할 때와 달리 뇌의 ‘배외측전전두피질’이 활성화되지 않는다는 사실을 밝혀냈다.

 

이번에 연구팀은 창의적인 활동과 뇌의 관계를 자세히 규명하기 위해 재즈 피아니스트에게 웃고 있는 여성 등 긍정적인 느낌의 사진과, 괴로워 하는 여성과 같은 부정적인 느낌의 사진을 보여주고 각각 그 느낌을 즉흥 연주로 표현하게 한 뒤, 연주자의 뇌를 기능성자기공명영상(fMRI) 장치로 촬영했다.

 

정확한 결과를 얻기 위해 사진 속 여성의 감정에 대해 전혀 언급하지 않고 오로지 연주자 스스로가 느낀 감정을 표현하게 했다. 또 즉흥적으로 연주할 때의 뇌 활성화 정도를 분석하기 위해 사진을 본 순간 나타난 뇌 반응은 전체 측정 결과에서 제외했다.

 

그 결과 긍정적인 감정을 표현할 때는 부정적인 감정을 표현할 때보다 배외측전전두피질의 활동이 크게 감소하는 것으로 나타났다. 부정적인 감정을 표현할 때는 뇌의 보상을 담당하는 다양한 영역들이 활성화됐다. 같은 즉흥 연주라 할지라도 연주자가 느끼고 표현하는 감정에 따라 뇌의 활동이 달라지는 셈이다.

 

연구팀은 기쁨과 슬픔을 연주할 때 뇌에서 서로 다른 메커니즘이 작용하기 때문에 이 같은 차이가 나타나는 것으로 추정했다.

 

림 교수는 “창의적인 활동과 뇌의 특정 영역 활성화의 연관성을 딱 잘라 설명할 수는 없다”면서도 “표현하는 감정에 따라 활성화 되는 영역과 강도에 차이가 있는 것만은 분명하다”고 말했다.

동아사이언스 염재윤 기자 dsjy@donga.com

Study of jazz pianists finds ‘happy’ and ‘sad’ music evoke different neural patterns

Jan 4, 2016 | Brain & Behavior

The workings of neural circuits associated with creativity are significantly altered when artists are actively attempting to express emotions, according to a new brain-scanning study of jazz pianists.

Over the past decade, a collection of neuroimaging studies has begun to identify components of a neural circuit that operates across various domains of creativity. But the new research suggests that creativity cannot be fully explained in terms of the activation or deactivation of a fixed network of brain regions. Rather, the researchers said, when creative acts engage brain areas involved in emotional expression, activity in these regions strongly influences which parts of the brain’s creativity network are activated, and to what extent.

“The bottom line is that emotion matters,” said senior author Charles Limb, MD. “It can’t just be a binary situation in which your brain is one way when you’re being creative and another way when you’re not. Instead, there are greater and lesser degrees of creative states, and different versions. And emotion plays a crucially important role in these differences.”

Most of the new research, which appears in the January 4, 2016 issue of Scientific Reports, was conducted in Limb’s laboratory at Johns Hopkins School of Medicine before his move to UC San Francisco in 2015. In his surgical practice, Limb, now the Francis A. Sooy Professor of Otolaryngology at UCSF and an accomplished jazz saxophonist, inserts cochlear implants to restore hearing.

Previous research by Limb and others using functional magnetic resonance imaging (fMRI) to study musical improvisation, freestyle rapping, and the rendering of caricatures–creative acts that unfold in real time and are therefore more amenable to laboratory studies than, say, painting–deactivate a brain region known as the dorsolateral prefrontal cortex (DLPFC), which is involved in planning and monitoring behavior. This DLPFC deactivation has been taken to be a neural signature of the “flow state” artists may enter to free up creative impulses.

But in the new study, led by first author Malinda McPherson, the researchers found that DLPFC deactivation was significantly greater when the jazz musicians, who played a small keyboard while in the fMRI scanner, improvised melodies intended to convey the emotion expressed in a “positive” image (a photograph of a woman smiling) than when they aimed to capture the emotions in a “negative” image (a photograph of the same woman in a mildly distressed state).

On the other hand, improvisations targeted at expressing the emotion in the negative image were associated with greater activation of the brain’s reward regions, which reinforce behaviors that lead to pleasurable outcomes, and a greater connectivity of these regions to the DLPFC.

“There’s more deactivation of the DLPFC during happy improvisations, perhaps indicating that people are getting into more of a ‘groove’ or ‘zone,’ but during sad improvisations there’s more recruitment of areas of the brain related to reward,” said McPherson, a classical violist and first-year graduate student in the Harvard-MIT Program in Speech and Hearing Bioscience and Technology. “This indicates there may be different mechanisms for why it’s pleasurable to create happy versus sad music.”

Because the images themselves might induce an emotional response in the musicians, in addition to the brain scans made while the musicians improvised, each scanning session also included a time period in which the musicians passively viewed the images. For each musician, any brain activity data generated during these passive viewing periods, including emotional responses, were subtracted from that elicited during their musical performances. This allowed the researchers to determine which components of brain activity in emotional regions were strongly associated with creating the improvisations.

Moreover, Limb said, the research team avoided biasing the musicians’ performances with words like “sad” or “happy” when instructing the musicians before the experiments.

“The notion that we can study complex creativity in artists and musicians from a neuroscientific perspective is an audacious one, but it’s one that we’re increasingly comfortable with,” Limb said. “Not that we’re going to answer all the questions, but that we have the right to ask them and to design experiments that try to shed some light on this fascinating human process.”

http://scienceblog.com/479939/study-jazz-pianists-finds-happy-sad-music-evoke-different-neural-patterns/#lKTsJlvRdYLb8d5k.97

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