Auditory Memories and Vocal Learning

描述（由申请人提供）：我们的听觉系统以多种多样的方式分析复杂的声波。首先，它提取特征，让我们感知节奏、音色和音高。与此同时，这些特征被结合起来，并与存储的记忆进行比较，从而产生更高层次的感知，如言语的意义、说话者的身份和她的情绪状态。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进行的。最后，我们的听觉系统也需要处理我们自己的声音来指导我们发声。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神经电路计算。在之前的工作中，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层的反应。我们已经证明，听觉神经元是专门代表自然声音的，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：中脑和丘脑的听觉神经元根据它们如何将声音分解成对不同听觉感知至关重要的特征，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层的解剖结构和微电路联系起来，2)开始解开导致观察到的功能专门化的细胞计算，3)研究初级和次级听觉皮层的计算，这些计算可以使系统处理噪声中的信号。为了实现这些目标，我们将在麻醉准备中记录单个神经元，使用多电极阵列进行细胞外记录或使用玻璃电极进行细胞内记录和免疫组织化学工作。我们还将使用小型电极驱动器记录清醒行为鸟类的神经活动。这些鸟将被放置在促使它们积极交流的环境中。在我们所有的实验中，我们将使用系统分析和信息论的最先进技术来分析神经元的调谐和选择性。我们的研究将阐明听觉皮层中不同回路在处理复杂声音（如语音和音乐）中的作用。这一知识对于理解某些精神障碍的听觉处理功能障碍如何影响语音识别以及其他认知技能至关重要。我们的工作也可能有助于听觉神经假肢的新信号处理方法的发展。

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.