Neuronal Substrates of Perceptual Salience in the Auditory System

你正站在部门的社交活动中，手里拿着一个塑料杯，无所事事地想着你的猫，同时多个正在进行的对话声淹没了你。突然，你听到其中一个对话中提到了你的名字，以前模糊的嗡嗡声变成了背景噪音和前景对话，现在命令你全神贯注。这是怎么发生的？知觉显著性在听觉脑中是如何表现的？听觉处理如何与行为状态和注意力相互作用，以区分听觉和听觉？我们最近开发了强大的新计算工具来解决这些问题，这使我们能够分析声音发生的背景如何影响听觉大脑中声音的表征。使用这些新的工具，我们发现，在听觉系统中的上下文敏感机制实现，在单神经元水平，众所周知的感知现象，描述人类如何解析复杂的声音到突出的事件。因此，这些上下文敏感机制可能是听觉系统中感知突显的神经元基底。我们假设，这些情境敏感机制的变化是主动倾听过程中感知显著性变化的基础--例如，当你突然意识到多个正在进行的对话中的一个声音是在谈论你时。我们将通过记录动物在两个不同的行为任务中注意听觉或视觉线索时，听觉皮层、丘脑和中脑神经元对复杂声音的反应来验证这一假设。通过比较大脑区域，感觉注意状态和行为任务之间的神经元的上下文依赖性，我们的目标是确定感知显着性如何从注意和神经元对声音上下文的敏感性之间的相互作用产生。最终，这项工作不仅可以揭示听觉系统中感知显着性的神经元基底，而且还可以为机器听力中未解决的问题提出新的方法-例如如何从多个正在进行的对话中提取单个语音的声音。

You are standing in the midst of a departmental social event with a plastic cup of wine in your hand, idly thinking about your cat, while the sound of multiple ongoing conversations washes over you. Suddenly, you hear your name mentioned in one of those conversations, and what was formerly an indistinct hum of voices separates into background noise and a foreground conversation that now commands your full attention. How does this happen? How is perceptual salience represented in the auditory brain? How does auditory processing interact with behavioural state and attention to differentiate hearing from listening?We have recently developed powerful new computational tools for addressing these questions, which have enabled us to analyse how the context in which a sound occurs affects the representation of that sound in the auditory brain. Using these novel tools, we have found that context-sensitive mechanisms in the auditory system implement, at a single-neuron level, well-known perceptual phenomena that describe how humans parse complex sounds into salient events. Therefore, these context-sensitive mechanisms may be the neuronal substrates of perceptual salience in the auditory system. We hypothesise that changes in these context-sensitive mechanisms underlie changes in perceptual salience during active listening - for example, when you suddenly realize that one individual voice in multiple ongoing conversations is talking about you.We will test this hypothesis by recording the responses of auditory cortical, thalamic and midbrain neurons to complex sounds while animals are attending to auditory or visual cues in two different behavioral tasks. By comparing the context-dependence of neurons between brain areas, sensory attentional states, and behavioural tasks, we aim to determine how perceptual salience arises from interactions between attention and neuronal sensitivity to sound context. Ultimately, this work may not only reveal the neuronal substrates of perceptual salience in the auditory system, but also suggest new approaches to unsolved problems in machine listening -- such as how to extract the sound of an individual voice from multiple ongoing conversations.