Rajendran Vani G, Harper Nicol S, Schnupp Jan W H
Auditory Neuroscience Group, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, UK.
Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong.
R Soc Open Sci. 2020 Mar 25;7(3):191194. doi: 10.1098/rsos.191194. eCollection 2020 Mar.
Previous research has shown that musical beat perception is a surprisingly complex phenomenon involving widespread neural coordination across higher-order sensory, motor and cognitive areas. However, the question of how low-level auditory processing must necessarily shape these dynamics, and therefore perception, is not well understood. Here, we present evidence that the auditory cortical representation of music, even in the absence of motor or top-down activations, already favours the beat that will be perceived. Extracellular firing rates in the rat auditory cortex were recorded in response to 20 musical excerpts diverse in tempo and genre, for which musical beat perception had been characterized by the tapping behaviour of 40 human listeners. We found that firing rates in the rat auditory cortex were on average higher on the beat than off the beat. This 'neural emphasis' distinguished the beat that was perceived from other possible interpretations of the beat, was predictive of the degree of tapping consensus across human listeners, and was accounted for by a spectrotemporal receptive field model. These findings strongly suggest that the 'bottom-up' processing of music performed by the auditory system predisposes the timing and clarity of the perceived musical beat.
先前的研究表明，音乐节拍感知是一个惊人复杂的现象，涉及高阶感觉、运动和认知区域广泛的神经协调。然而，关于低级听觉处理如何必然塑造这些动态，进而影响感知，目前还没有得到很好的理解。在这里，我们提供证据表明，即使在没有运动或自上而下激活的情况下，音乐在听觉皮层的表征已经偏向于即将被感知的节拍。我们记录了大鼠听觉皮层的细胞外放电率，以响应20段节奏和风格各异的音乐片段，40名人类听众的敲击行为已对这些音乐片段的节拍感知进行了表征。我们发现，大鼠听觉皮层的放电率在节拍上平均高于节拍外。这种“神经强化”将被感知的节拍与节拍的其他可能解释区分开来，预测了人类听众之间敲击的一致程度，并且可以由一个频谱时间感受野模型来解释。这些发现有力地表明，听觉系统对音乐的“自下而上”处理预先决定了所感知音乐节拍的时间和清晰度。
