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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631395
• 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“节奏”的能力。这种复杂的能力是普遍的，并且是在生命早期自发获得的。然而，正如我们最近所展示的那样，有些人无法找到音乐的节拍，也无法与之同步，尽管他们的听力、运动和智力都很正常。这种疾病，我们称之为突发性耳聋（一种新形式的先天性失音症），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产生的，以及它是如何在大脑中表达的。本建议的目的是表征跳动性耳聋的功能和神经异常。为此，我们将招募和测试异常组（殴打聋人）和对照组成年人。我们将根据第一个病例的诊断标准来选择打聋的成年人。它的基本行为表现是身体动作与舞曲选择的不同步，这是通过动作捕捉来衡量的。这种紊乱似乎只出现在节奏上，因为它忽略了对旋律音高的处理。因此，节拍性耳聋不同于最常见的先天性失音，即影响音高加工的音高耳聋。在控制贫乏的音乐体验的同时，对节拍失聪和音高失聪表演的比较将有助于区分基于节拍的娱乐。在提案的第一部分中，我们将研究如何在节拍跟踪缺陷可以揭示人类基于节拍的娱乐特征。通常情况下，人们在节拍之前敲击，以消除由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，与对照组和音高失聪的表现相比，失聪的个体在节拍器样刺激下的预期叩击时是否更具反应性或表现出更强的偏好内生速率影响。在第二部分中，我们将测试娱乐机制的音乐特异性。我们预测，正常的参与者对歌曲的敲击应该比正常的演讲更少，更少的不同步。相比之下，失聪的人无论在自然的、正常的语言还是歌曲中演奏，都应该同样糟糕，而音高失聪的表现则会表现出相反的模式，在正常的语言中表现最好，因为歌曲包含干扰性的音高变化。在第三部分中，我们将使用一种新的电生理（EEG）技术来测量神经对音乐的影响，该技术可以捕获与热相关的稳态诱发电位，这是基于自然的大脑振荡可以被听觉刺激的周期性所吸引的想法。在节拍失聪的听者的大脑中，存在内部节拍表征的证据应该很弱。另一种有趣的解释是，脑电图显示的是正常的听觉神经活动，而不是敲击。这一发现表明，这种缺陷不是感性的，而是由听觉-运动耦合不良引起的。最后，在第四部分中，我们将用几种磁共振成像（MRI）技术寻找脑异常，这些技术已被证明在音高耳聋中具有信息。搏动性耳聋提供了一个难得的机会来识别神经网络的哪些部分（从基底神经节到背侧运动前皮层）对带音至关重要。通过结合这些不同的神经心理学方法，本项目将为人类节律的神经生物学基础提供理论见解。