有人對音樂沒感覺? 新研究認爲這也許是種病!
Have you ever met someone who just wasn't into music? They may have a condition called specific musical anhedonia, which affects three-to-five percent of the population.
你有沒有遇到過一些人，他們就是不喜歡音樂？他們或許患有一種被稱作特異性音樂快感缺乏症的疾病，這樣的人在全球總人口中佔3%到5%。Researchers at the University of Barcelona (Spain) and the Montreal Neurological Institute and Hospital of McGill University (Canada) have discovered that people with this condition showed reduced functional connectivity between cortical regions responsible for processing sound and subcortical regions related to reward.
來自西班牙巴塞羅那大學、加拿大蒙特利爾神經學研究所和麥基爾大學醫院的研究人員發現，患這種病的人，他們負責處理聲音的腦皮層區域與處理獎賞的皮層下區域之間的連通性較弱。To understand the origins of specific musical anhedonia, researchers recruited 45 healthy participants who completed a questionnaire measuring their level of sensitivity to music and divided them into three groups of sensitivity based on their responses.
爲了理解這種特異性音樂快感缺乏症的根源，研究人員招募了45位健康人士完成了一份測試其對音樂敏感度的問卷，並根據測試結果將他們分成了三組。
The test subjects then listened to music excerpts inside an fMRI machine while providing pleasure ratings in real-time. To control for their brain response to other reward types, participants also played a monetary gambling task in which they could win or lose real money.
隨後，接受測試的人會在功能性磁共振成像機內聆聽一段音樂，並實時提供快樂評級。爲了控制在其他獎勵類型時大腦的反應，參與者還用真錢玩起了賭博。
Using the fMRI data, the researchers found that while listening to music, specific musical anhedonics presented a reduction in the activity of the nucleus accumbens, a key subcortical structure of the reward network.
研究人員分析功能性磁共振成像數據發現，特異性音樂快感缺乏症患者聽音樂時，獎賞系統的關鍵皮層下結構伏隔核的活動較弱。The reduction was not related to a general improper functioning of the nucleus accumbens itself, since this region was activated when they won money in the gambling task.
這種減弱並不意味着伏隔核本身功能失常，因爲當這些患者在賭博中贏錢時，該區域就會被激活。Specific musical anhedonics, however, did show reduced functional connectivity between cortical regions associated with auditory processing and the nucleus accumbens. In contrast, individuals with high sensitivity to music showed enhanced connectivity.
不過，特異性音樂快感缺乏症患者處理聲音的皮層區域與伏隔核的連通性卻減弱了。相比之下，對音樂高度敏感的人二者之間的連通性增強了。The fact that subjects could be insensible to music while still responsive to another stimulus like money suggests different pathways to reward for different stimuli.
研究參與者對音樂麻木，卻對金錢等其他刺激物產生反應，這說明針對不同刺激物，獎賞通路不同。This finding may pave the way for the detailed study of the neural substrates underlying other domain-specific anhedonias and, from an evolutionary perspective, help us to understand how music acquired reward value.
這一發現或許能爲詳細研究其他快感缺乏症的神經學機制打下基礎，且能從革命性視角幫助我們理解音樂是如何獲得獎賞價值的。Lack of brain connectivity has been shown to be responsible for other deficits in cognitive ability.
研究發現，大腦連通性缺失也與認知能力的其他缺陷相關。Studies of children with autism spectrum disorder, for example, have shown that their inability to experience the human voice as pleasurable may be explained by a reduced coupling between the bilateral posterior superior temporal sulcus and distributed nodes of the reward system, including the nucleus accumbens.
比如，針對泛自閉症障礙兒童開展的研究顯示，他們之所以不能從人類的聲音中體會快樂，可能是因爲後顳上溝與伏隔核等獎賞系統的分佈式節點連通不足。"These findings not only help us to understand individual variability in the way the reward system functions, but also can be applied to the development of therapies for treatment of reward-related disorders, including apathy, depression, and addiction," says Robert Zatorre, a Montreal Neurological Institute neuroscientist and one of the paper's co-authors.
該研究論文的作者之一、蒙特利爾神經學研究所的神經學家羅伯特·扎託雷說：“這些研究成果不僅幫助我們理解獎賞系統運行方式的個體差異，還可用於開發治療冷漠、抑鬱和成癮等與獎賞有關疾病的方法。”
