Evaluating the neural mechanisms of stream segregation using naturalistic sounds in behaving primates

使用自然声音评估灵长类动物行为的流分离的神经机制

• 批准号: 9912631
• 负责人: Luke Abraham Shaheen
• 金额: $ 6.74万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9912631
• 关键词: Affect; Animal Model; Area; Attention; Auditory; Auditory area; Auditory system; Behavior; Brain; Callithrix; Code; Communication; Complex; Comprehension; Controlled Study; Crowding; Data; Electrodes; Environment; Frequencies; Hearing Aids; Human; Individual; Lateral; Location; Modeling; Neurons; Perception; Performance; Periodicity; Peripheral; Physiological; Population; Population Dynamics; Primates; Role; Self-Help Devices; Signal Transduction; Source; Speech; Stimulus; Stream; Technology; Testing; Work; base; design; directed attention; experimental study; hearing impairment; improved; neuromechanism; normal hearing; psychologic; relating to nervous system; response; segregation; selective attention; sound; tool

Project Summary The neural mechanisms used by the auditory system to isolate and comprehend a single speaker out of a background of other speakers are currently unknown. Young, normal-hearing individuals are capable of understanding a single speaker in complex auditory environments, while individuals with hearing loss and even some older individuals without hearing loss struggle in the same settings. A first step in ultimately designing technology to restore the ability to follow a single speaker in a crowded room is to understand how the normal auditory system achieves this feat. Human speech is composed of components that span a broad frequency range. The peripheral auditory system separates the incoming signal by spectral frequency, yet the perception of a single speaker is that of a single entity. This percept defines an auditory stream: a group of sound features that appear to originate from a single source. Pioneering work over several decades has led to a basic understanding of the psychological and physiological mechanisms of streaming simple sounds, arriving at the population separation model: the perception of unique sound sources occurs when neural responses to each source are separated into unique neural populations. For simple sounds, population separation may be inherent in the frequency separation of sources, or computed in the peripheral auditory system. However, how separation is achieved for more complex sounds with overlapping frequency content is unknown. One proposed mechanism is temporal coherence – the idea that coincident fluctuations in the amplitude of distinct features become bound together into a single perceived stream. While the effects of temporal coherence on population separation have been tested with synthetic, periodic stimuli, these results are not likely to generalize to those of natural sounds, which contain complex temporal envelopes. Therefore, we will examine auditory streaming using naturalistic speech-like stimuli: two distinct harmonic complex tones that are modulated by temporal envelopes drawn from human speech. When modulated with different envelopes, these stimuli are temporally incoherent and evoke a strong percept of two separate streams; when modulated with identical envelopes they are coherent and are perceived as a single stream. We will collect single-neuron responses to these stimuli in marmoset auditory cortex to assess the impact of temporal coherence (and streaming) on neural encoding. We will then engage marmosets in a task requiring streaming of these sounds and quantify the effects of directed attention on neural encoding. These results will be useful in refining models of stream segregation, laying the groundwork for controlled studies using fully natural sounds.

项目概要 听觉系统用来分离和理解单个说话者的神经机制 目前尚不清楚其他发言者的背景。听力正常的年轻人有能力 在复杂的听觉环境中理解单个说话者，而听力损失甚至听力损失的人 一些没有听力损失的老年人在同样的环境中也遇到了困难。最终设计的第一步 恢复在拥挤的房间里跟随单个说话者的能力的技术是了解正常情况下如何 听觉系统实现了这一壮举。 人类语音由跨越广泛频率范围的成分组成。外周听觉 系统通过频谱频率分离输入信号，但单个扬声器的感知是一个扬声器的感知 单一实体。这种感知定义了听觉流：一组似乎源自某个声音的声音特征。 单一来源。几十年来的开创性工作已经使人们对心理和心理有了基本的了解。 流式传输简单声音的生理机制，得出群体分离模型： 当对每个声源的神经反应被分成独特的时，就会产生对独特声源的感知。 神经群体。对于简单的声音，总体分离可能是固有的频率分离 源，或在外围听觉系统中计算。然而，如何实现更多分离 具有重叠频率内容的复杂声音是未知的。一种提议的机制是时间性的 相干性——不同特征幅度的一致波动被束缚在一起的想法 进入单个感知流。 虽然时间相干性对群体分离的影响已经通过合成的、周期性的测试 刺激，这些结果不太可能推广到自然声音，其中包含复杂的时间 信封。因此，我们将使用自然语音刺激来检查听觉流：两种不同的 由人类语音中提取的时间包络调制的和声复杂音调。什么时候 用不同的包络进行调制，这些刺激在时间上是不连贯的，并唤起两种强烈的感知 单独的流；当用相同的包络进行调制时，它们是连贯的并且被视为单个包络 溪流。我们将收集狨猴听觉皮层中这些刺激的单神经元反应，以评估 时间一致性（和流）对神经编码的影响。然后我们将让狨猴参与一项任务 需要这些声音的流动并量化定向注意力对神经编码的影响。这些 结果将有助于完善河流分离模型，为对照研究奠定基础 使用完全自然的声音。