Losing the beat: brain and behavior basis of human rhythm

失去节拍：人类节奏的大脑和行为基础

• 批准号: RGPIN-2014-04068
• 负责人: Peretz, Isabelle
• 金额: $ 3.57万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566273
• 关键词: Losing; beat; brain; behavior; basis

A defining characteristic of our interactions with music is the ability to identify and move to the “beat”. This complex ability is universal and spontaneously acquired early in life. Yet, as we have recently shown, some individuals fail to find the beat in music and to synchronize with it, despite having normal hearing, normal motor and intellectual abilities. This disorder, to which we refer as beat deafness (a new form of congenital amusia), provides a natural experiment, a rare chance to examine how a selective cognitive deficit emerges and how it is expressed in the brain. The goal of this proposal is to characterize the functional and neural anomalies of beat deafness. To this aim, we will recruit and test groups of abnormal (beat deaf) and control adults. Beat-deaf adults will be selected according to the same criteria as those used to diagnose our first case. Its essential behavioral manifestation is poor synchronization of body movements to selections of dance music, as measured by motion capture. The disorder appears specific to rhythm because it spares melodic pitch processing. Hence beat deafness is distinct from the most common form of congenital amusia, pitch deafness that affects pitch processing. The comparison of beat-deaf and pitch-deaf performance will serve to fractionate beat-based entrainment while controlling for impoverished musical experience. In PART I of the proposal, we will examine how deficits in beat-tracking can shed light on characteristics of human beat-based entrainment. Typically, people tap in advance of the beat to eliminate the time lag introduced by sensorimotor reaction. Such anticipatory tendencies are considered to be unique to humans. We will test here whether beat-deaf individuals are more reactive or exhibit stronger influences of preferred endogenous rates in anticipatory tapping to metronome-like stimuli as compared to control and pitch-deaf performance. In PART II, we will test the music-specificity of entrainment mechanisms. We predict that normal participants should tap less variably and with fewer asynchronies to song than to regular speech. In contrast, beat deaf individuals should be equally poor whether they tap on natural, regular speech or songs, and pitch deaf performance will show the opposite pattern with best performance on regular speech since songs contain interfering pitch variations. In PART III, neural entrainment to music will be measured with a novel electrophysiological (EEG) technique that captures beat-related steady-state evoked potentials, following the idea that natural brain oscillations can entrain to the periodicities of the auditory stimulus. In the brains of beat deaf listeners, the evidence for the presence of an internal representation of the beat should be weak. An interesting alternative is that the EEG reveals normal neural entrainment in listening but not in tapping. Such a finding would suggest that the deficit is not perceptual but arises from poor auditory-motor coupling. Finally, in PART IV, we will search for brain anomalies with several Magnetic Resonance Imaging (MRI) techniques that have proven to be informative in pitch deafness. Beat deafness represents a rare chance to identify which parts of the neural network (from the basal ganglia to the dorsal premotor cortex) are essential for entrainment. By combining these diverse neuropsychological methods, this project should provide theoretical insight on the neurobiological basis of human rhythm.

我们与音乐互动的一个决定性特征是识别并跟随“节拍”的能力。这种复杂的能力是普遍存在的，而且是在生命早期自发获得的。然而，正如我们最近所展示的，一些人无法在音乐中找到节拍并与之同步，尽管他们拥有正常的听力、正常的运动和智力能力。这种疾病，我们称之为拍击性耳聋(一种新的先天性失语症)，提供了一个自然的实验，一个难得的机会来研究选择性认知缺陷是如何出现的，以及它是如何在大脑中表达的。这项建议的目的是描述拍击性耳聋的功能和神经异常。为此，我们将招募和测试变态(打耳聋)和对照成人群体。将根据与诊断我们第一个病例相同的标准来选择打击性耳聋成年人。它的基本行为表现是身体动作与舞曲选择的不同步，通过动作捕捉来衡量。这种紊乱似乎是特定于节奏的，因为它省去了旋律的音调处理。因此，节拍性耳聋不同于最常见的先天性失语症，也就是影响音调处理的音调失聪。对节拍聋人和音调聋人的表演进行比较，将有助于在控制贫乏的音乐体验的同时，进行基于节拍的碎片式夹带。在提案的第一部分，我们将研究节拍跟踪的缺陷如何揭示人类基于节拍的夹带的特征。通常，人们会在节拍之前敲击，以消除感觉运动反应带来的时间滞后。这种预期倾向被认为是人类独有的。我们将在这里测试，与对照和音调失聪的表现相比，在对节拍器样刺激的预期敲击中，拍击失聪个体是否更具反应性，或者表现出更强的优先内源性频率的影响。在第二部分，我们将测试卷吸机制的音乐专一性。我们预测，与正常说话相比，正常参与者应该更少地敲击可变的歌曲，并且与歌曲的不同步更少。相比之下，被打耳聋的人无论是使用自然的、常规的语音还是歌曲，都应该同样糟糕，而音调聋人的表现将显示出相反的模式，在常规语音中表现最好，因为歌曲包含干扰的音调变化。在第三部分中，将使用一种新的电生理(EEG)技术来测量神经对音乐的夹带，该技术捕获与节拍相关的稳态诱发电位，遵循自然大脑振荡可以夹带到听觉刺激的周期性的想法。在节拍失聪的听者的大脑中，存在节拍的内部表征的证据应该很弱。另一种有趣的选择是，脑电波显示正常的神经在倾听时的缠绕，而不是在敲击时。这样的发现将表明，这种缺陷不是知觉的，而是由听觉-运动耦合不良引起的。最后，在第四部分中，我们将使用几种磁共振成像(MRI)技术来寻找大脑异常，这些技术已经被证明在音调聋方面是有信息的。拍击性耳聋代表着一个难得的机会，可以确定神经网络的哪些部分(从基底节到背侧运动前皮质)是夹带所必需的。通过结合这些不同的神经心理学方法，这个项目应该为人类节律的神经生物学基础提供理论上的见解。