Auditory Information Processing in the Midbrain

描述：(改编自申请者摘要)：本项目的长期目标 研究的目的是确定导致编码的机制和途径 以及由语音通信信号传达的信息的表示。 通过声音进行的通信使用频谱和时间复数信号，以及 他们在中枢神经系统中的分析需要整合 信号中的光谱和时间元素。这样的整合，曾经 被认为是听觉皮质的唯一作用，现在似乎发生在 皮质下听觉区域。这项建议集中在神经机制上。 以及听觉中时间和频谱整合的结构特征 中脑。了解在哪里以及在什么类型的专业处理 类似言语的声音发生在通往听觉皮质的特定通路上 对语言知觉障碍的基础有更全面的了解 和潜在的干预策略。时间和频率敏感的一种形式 整合，在各种脊椎动物的前脑中很常见，是 由组合神经元执行，当不同的光谱时响应最好 发声中的元素在特定的时间关系中组合在一起。这个 拟议中的研究考察了组合反应如何以及在哪里产生 长胡子的蝙蝠。在这个物种的听觉皮质中，组合 反响丰富，特征明确，有很好的 理解它们在声纳和社会交流中的潜在意义 行为。这些神经元在下丘(IC)也很丰富， 可能在那里形成。 前两个具体目标是研究脑干听觉神经元如何发挥作用。 对下丘的组合反应进行分析 蝙蝠的声纳会发出回声。第一个目标是检查神经生理学 耳蜗核中神经元的特性可能有助于 这些组合反应的构造。第二个目标是使用 顺行追踪方法确定来自听觉的投射 脑干为组合神经元进行频率整合提供了基础 在下丘。第三个具体目的是使用生理记录 和局部药物应用，以检查在 下丘产生时间敏感的易化作用 描述了组合反应的特征。第四个具体目标使用相同的 用生理学/药理学技术研究一类组合 可能会对社会发声做出反应的神经元。这一目标将检验是否 经过充分研究的组合之间存在着基本的机械联系 分析声纳回声和分析其他复杂声音的神经元， 比如社交发声。这些机制可能类似于 在语音分析的早期阶段进行操作。

DESCRIPTION: (Adapted from applicant's abstract): The long term goal of this research is to identify mechanisms and pathways that give rise to the encoding and representation of information conveyed by vocal cornmuniction signals. Communication by sound employs spectrally and temporally complex signals, and their analyses in the central nervous system require integration across spectral and temporal elements in the signals. Such integration, once considered an exclusive role of auditory cortex, now appears to occur in sub-cortical auditory regions. This proposal focuses on the neuronal mechanisms and structural features of temporal and spectral integration in the auditory midbrain. Understanding where and what types of specialized processing of speech-like sounds occurs in particular pathways to auditory cortex will provide a fuller understanding of the bases of language perception disorders and potential intervention strategies.One form of time- and frequency-sensitive integration, common in the forebrains of a wide range of vertebrates, is performed by combinatorial neurons that respond best when distinct spectral elements in vocalizations are combined in specific temporal relationships. The proposed research examines how and where combinatorial responses originate in the mustached bat. In the auditory cortex of this species, combinatorial responses are abundant and well-characterized, and there is a good understanding of their potential significance in sonar and social communication behaviors. These neurons are also abundant in the inferior colliculus (IC), and may be formed there. The first two specific aims examine how brainstem auditory neurons contribute to the combinatorial responses in the inferior colliculus that analyze the bat's sonar echoes. The first aim will examine the neurophysiological properties of neurons in the cochlear nucleus that may contribute to the construction of these combinatorial responses. The second aim is to use anterograde tracing methods to determine what projections from the auditory brainstem provide the basis for frequency integration by combinatorial neurons in the inferior colliculus. The third specific aim uses physiological recording and local application of drugs to examine the mechanisms operating in the inferior colliculus that create the temporally sensitive facilitation that characterizes combinatorial responses. The fourth specific aim uses the same physiological/pharmacological techniques to study a class of combinatorial neurons that may respond to social vocalizations. This aim will test whether there is a fundamental mechanistic link between the well-studied combinatorial neurons that analyze sonar echoes and those that analyze other complex sounds, such as social vocalizations. These mechanisms may be similar to those operating at early stages in the analysis of speech sounds.