Auditory Memories and Vocal Learning

描述(申请人提供)：我们的听觉系统以惊人的多样性分析复杂的声音波形。首先，它提取能让我们感知节奏、音色和音高的特征。同时，这些特征被组合在一起，并与存储的记忆进行比较，以产生更高阶的感知，如语音的意义、说话人的身份和她的情感状态。其次，这些听觉任务通常是在环境噪声或其他干扰声信号的背景下执行的。最后，我们的听觉系统还需要处理我们自己的声音来指导我们的发声。我们建议研究鸣禽的听觉系统，作为一个模型系统，以了解这些不同能力背后的电路的神经计算。在以前的工作中，我们已经描述了鸟类听觉中脑、丘脑以及初级和次级听觉皮质的反应。我们已经证明了听觉神经元是专门用来代表自然声音的，我们可以从它们的调谐特性来解释这种专门化。我们还发现了平行功能处理流的证据：中脑和丘脑的听神经元根据它们将声音分解为对不同听觉感知至关重要的特征的方式，分为不同的功能类型。我们这个项目的主要目标是1)将神经元的功能特性与听觉皮质的解剖和微电路联系起来，2)开始解开导致观察到的功能特化的细胞计算，以及3)研究初级和次级听觉皮质中允许系统在噪声中处理信号的计算。为了实现这些目标，我们将从麻醉准备中的单个神经元进行记录，无论是使用多电极阵列进行细胞外记录，还是使用玻璃电极进行细胞内记录和免疫组织化学工作。我们还将使用微型电极驱动器记录清醒状态下鸟类的神经活动。这些鸟将被放置在促使它们积极交流的环境中。在我们的所有实验中，我们将使用系统分析和信息论的最新技术来分析神经元的调节和选择性。我们的研究将阐明听觉皮质中不同回路在处理语音和音乐等复杂声音方面的作用。这些知识对于理解某些精神障碍中的功能失调的听觉处理如何影响语音识别和其他认知技能至关重要。我们的工作也可能对开发新的听觉神经假体信号处理方法起到重要作用。

DESCRIPTION (provided by applicant): Our auditory system analyzes complex sound waveforms in an amazing diversity of ways. First, it extracts features that give us the percepts of rhythm, timbre and pitch. Simultaneously those features are combined and compared to stored memories to produce higher-order percepts such as the meaning of speech, the speaker's identity and her emotional state. Second, these auditory tasks are often performed with environmental noise or other interfering acoustical signals in the background. Finally, our auditory system needs also to process the sound of our own voice to guide our vocalizations. We propose to study the auditory system of songbirds as a model system to understand the neural computations of circuitry underlying these diverse abilities. In previous work, we have characterized responses in the avian auditory midbrain, thalamus and in the primary and secondary auditory cortex. We have shown that auditory neurons are specialized to represent natural sounds and that we can explain this specialization from their tuning properties. We also found evidence for parallel functional processing streams: auditory neurons in the midbrain and thalamus fall into different functional types based on how they decompose sound into features that are crucial for different auditory percepts. Our major goals for this project are 1) to relate the functional properties of neurons to the anatomy and microcircuitry of the auditory cortex, 2) to begin to unravel the cellular computations that lead to the observed functional specialization and 3) to investigate the computations in the primary and secondary auditory cortex that could allow the system to process signals in noise. To achieve these goals we will record from single neurons in the anesthetized preparation, both with multi-electrode arrays for extracellular recordings or with glass electrodes for intracellular recordings and immunohistochemical work. We will also record neural activity in awake behaving birds using a miniaturized electrode drive. The birds will be placed in situations that elicit them to actively communicate. In all our experiments, we will analyze the neurons' tuning and selectivity using state-of-the-art techniques from systems analysis and information theory. Our studies will elucidate the roles of different circuits within auditory cortex in processing complex sounds such as speech and music. This knowledge will be essential to understand how dysfunctional auditory processing in certain mental disorders affects speech recognition and consequently other cognitive skills. Our work could also be instrumental in the development of novel signal processing methods for auditory neural prosthetics.