Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Faculty of Science and Technology, Bournemouth University, Poole, United Kingdom.
PLoS Comput Biol. 2019 Feb 28;15(2):e1006820. doi: 10.1371/journal.pcbi.1006820. eCollection 2019 Feb.
Pitch is a fundamental attribute of auditory perception. The interaction of concurrent pitches gives rise to a sensation that can be characterized by its degree of consonance or dissonance. In this work, we propose that human auditory cortex (AC) processes pitch and consonance through a common neural network mechanism operating at early cortical levels. First, we developed a new model of neural ensembles incorporating realistic neuronal and synaptic parameters to assess pitch processing mechanisms at early stages of AC. Next, we designed a magnetoencephalography (MEG) experiment to measure the neuromagnetic activity evoked by dyads with varying degrees of consonance or dissonance. MEG results show that dissonant dyads evoke a pitch onset response (POR) with a latency up to 36 ms longer than consonant dyads. Additionally, we used the model to predict the processing time of concurrent pitches; here, consonant pitch combinations were decoded faster than dissonant combinations, in line with the experimental observations. Specifically, we found a striking match between the predicted and the observed latency of the POR as elicited by the dyads. These novel results suggest that consonance processing starts early in human auditory cortex and may share the network mechanisms that are responsible for (single) pitch processing.
音高是听觉感知的基本属性。同时出现的音高相互作用会产生一种感觉，可以用其和谐或不和谐的程度来描述。在这项工作中，我们提出人类听觉皮层（AC）通过在早期皮层水平上运行的共同神经网络机制来处理音高和和谐。首先，我们开发了一个新的包含现实神经元和突触参数的神经集合模型，以评估 AC 早期阶段的音高处理机制。接下来，我们设计了一个脑磁图（MEG）实验来测量具有不同和谐或不和谐程度的对偶体引起的神经磁活动。MEG 结果表明，不和谐的对偶体引起的音高起始反应（POR）潜伏期比和谐的对偶体长 36 毫秒。此外，我们使用该模型来预测并发音高的处理时间；在这里，和谐的音高组合比不和谐的组合解码更快，与实验观察结果一致。具体来说，我们发现模型预测的和实验观察的 POR 潜伏期之间存在惊人的匹配，这表明和谐处理在人类听觉皮层中很早就开始了，并且可能共享负责（单一）音高处理的网络机制。
