Chapuis Gaëlle A, Chadderton Paul T
Department of Bioengineering, Imperial College London, London, United Kingdom.
School of Physiology, Pharmacology and Neuroscience, University Walk, University of Bristol, Bristol, United Kingdom.
Front Behav Neurosci. 2018 Sep 11;12:205. doi: 10.3389/fnbeh.2018.00205. eCollection 2018.
Auditory streaming is the process by which environmental sound is segregated into discrete perceptual objects. The auditory system has a remarkable capability in this regard as revealed in psychophysical experiments in humans and other primates. However, little is known about the underlying neuronal mechanisms, in part because of the lack of suitable behavioural paradigms in non-primate species. The mouse is an increasingly popular model for studying the neural mechanisms of perception and action because of the range of molecular tools enabling precise manipulation of neural circuitry. Here we present a novel behavioural task that can be used to assess perceptual aspects of auditory streaming in head-fixed mice. Animals were trained to detect a target sound in a one of two simultaneously presented, isochronous pure tone sequences. Temporal expectation was manipulated by presenting the target sound in a particular stream either early (2 s) or late (4 s) with respect to trial onset in blocks of 25-30 trials. Animals reached high performance on this task ( > 1 overall), and notably their false alarms were very instructive of their behavioural state. Indeed, false alarm timing was markedly delayed for late blocks compared to early ones, indicating that the animals associated a different context to an otherwise identical stimulus. More finely, we observed that the false alarms were timed to the onset of the sounds present in the target stream. This suggests that the animals could selectively follow the target stream despite the presence of a distractor stream. Extracellular electrophysiological recordings during the task revealed that sound processing is flexibly modulated in a manner consistent with the optimisation of behavioural outcome. Together, these results indicate that the perceptual streaming can be inferred via the timing of false alarms in mice, and provide a new paradigm with which to investigate neuronal mechanisms of selective attention.
听觉流是将环境声音分离为离散感知对象的过程。人类和其他灵长类动物的心理物理学实验表明，听觉系统在这方面具有非凡的能力。然而，对于其潜在的神经元机制知之甚少，部分原因是缺乏适用于非灵长类物种的合适行为范式。由于有一系列能够精确操纵神经回路的分子工具，小鼠正日益成为研究感知和行为神经机制的流行模型。在此，我们提出了一种新颖的行为任务，可用于评估固定头部的小鼠听觉流的感知方面。动物被训练在两个同时呈现的等时纯音序列之一中检测目标声音。通过在25 - 30次试验的块中，相对于试验开始，在特定流中早期（约2秒）或晚期（约4秒）呈现目标声音来操纵时间预期。动物在这项任务上表现出色（总体> 1），值得注意的是，它们的误报对其行为状态具有很大的指导意义。事实上，与早期块相比，晚期块的误报时间明显延迟，这表明动物将不同的情境与原本相同的刺激联系起来。更精确地说，我们观察到误报时间与目标流中存在的声音开始时间一致。这表明尽管存在干扰流，动物仍可以选择性地跟随目标流。任务期间的细胞外电生理记录表明，声音处理以与行为结果优化一致的方式灵活调制。总之，这些结果表明，可以通过小鼠误报的时间来推断感知流，并提供了一种新的范式来研究选择性注意的神经元机制。
