Neuronal coding of communication sounds in the central nucleus of the mouse auditory midbrain (inferior colliculus): time-domain analyses

对诸如动物的一系列交流叫声或人类语言中的音节和单词等声学对象流进行编码是哺乳动物听觉系统的“日常事务”。人类的心理声学和生理实验表明，在时间常数接近20、100和400毫秒时，对声学物体和听觉流的感知发生转变。在对家鼠的行为研究中，当它们感知并回应自己的交流呼叫时，也发现了感知声音改变其听觉质量的时域值。因此，小鼠是一个足够的动物模型来测试这些时间常数是否已经在声音处理的皮层下水平作为感知转换的一般时间窗口发生，我们对听觉对象和流的编码知之甚少。因此，本电生理实验旨在分析听觉中脑主核（下丘中央核）在单个神经元水平和全局水平上对感知相关时间常数的编码。结果表明，听觉中脑的神经元反应对听觉客体在时间域的形成和节奏（听觉客体流）的编码的贡献。这些数据是新的，具有普遍重要性，因为它们直接将中脑的神经元处理和编码与哺乳动物听觉感知的共同特性联系起来。

Coding of streams of acoustic objects such as series of communication calls of animals or syllables and words in human speech is the “daily business” of mammalian auditory systems. Psychoacoustical and physiological experiments in humans have shown transitions in the perception of acoustic objects and auditory streams that occur with time constants near 20, 100, and 400 ms. These values in the time domain at which perceived sounds change their auditory quality have been found also in behavioral studies of house mice when they perceive and respond to their own communication calls. Thus, the mouse is an adequate animal model to test whether these time constants occur as general time windows of perceptual transition already at the subcortical level of sound processing, of which we know very little with regard to coding of auditory objects and streams. Hence, the present electrophysiological experiments were designed to analyze the main nucleus of the auditory midbrain (central nucleus of the inferior colliculus) with regard to coding the perceptually relevant time constants at the single neuron level and at the global level. Results are expected about the contribution of neuronal responses in the auditory midbrain to auditory object formation in the time domain and the coding of rhythms (streams of auditory objects). Such data are new and of general importance since they directly relate neuronal processing and coding in the midbrain to common properties of mammalian auditory perception.