FUNCTIONAL ANATOMY OF THE AUDITORY PATHWAYS

听觉通路的功能解剖学

• 批准号: 6379539
• 负责人: Brett R Schofield
• 金额: $ 17.93万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6379539
• 关键词: auditory cortex; auditory feedback; auditory nuclei; auditory pathways; brain stem; fluorescent dye /probe; guinea pigs; neural information processing; neuroanatomy

The auditory system consists of ascending pathways that transmit information from the ear to the cortex, where sound is perceived, and descending pathways from the cortex that modulate the processing and flow of ascending information. The descending pathways play a role in a wide variety of functions, including selective attention, learning, frequency selectivity, sound localization, and discrimination of speech sounds. Much of the previous work on descending pathways has focused on projections from the brainstem to the cochlea. Characterization of the morphology, physiology and transmitter chemistry of the cells that project to the cochlea has led to major advances in our understanding of this olivocochlear system. Our understanding of the remaining descending pathways, some of which involve many more cells than the olivocochlear system, lags far behind. We propose to use combinations of sensitive new anatomical tracing techniques to examine the functional organization of some of the largest components of the descending auditory pathways. Our experiments are focused on the projections from the auditory cortex to the brainstem auditory nuclei. The importance of this pathway was highlighted by recent discoveries that the cortical projections are far more extensive than previously believed, extending as far as the cochlear nucleus, which is the site of entry of auditory information into the brain. One goal of our experiments is to identify the brainstem circuits that are contacted directly by descending projections from the cortex. A second goal is to identify the anatomical relationships between the cells that give rise to the descending projections and the functional organization of auditory cortex. The results should provide insights into the types of information being transmitted by the descending projections as well as the identity of the brainstem circuits that are affected by these projections. This information will provide in turn an anatomical basis for interpreting the results from other types of studies and, eventually, help us understand the role of the descending pathways in both the normal and the diseased or damaged brain.

听觉系统由将信息从耳朵传输到感知声音的皮层的上行通路和调节上行信息的处理和流动的来自皮层的下行通路组成。 下行通路在多种功能中发挥作用，包括选择性注意、学习、频率选择性、声音定位和语音辨别。 之前关于下行通路的大部分工作都集中在从脑干到耳蜗的投射上。 对投射到耳蜗的细胞的形态、生理学和递质化学的表征使我们对橄榄耳蜗系统的理解取得了重大进展。 我们对其余下行通路的理解远远落后，其中一些下行通路涉及的细胞数量比橄榄耳蜗系统多得多。 我们建议结合使用敏感的新解剖追踪技术来检查下行听觉通路一些最大组成部分的功能组织。我们的实验重点是从听觉皮层到脑干听觉核团的投射。 最近的发现突显了这条通路的重要性，即皮质投射比以前认为的要广泛得多，一直延伸到耳蜗核，耳蜗核是听觉信息进入大脑的部位。 我们实验的目标之一是识别通过皮层的下降投射直接接触的脑干回路。 第二个目标是确定产生下降投射的细胞与听觉皮层功能组织之间的解剖关系。 结果应该可以深入了解下降投影传输的信息类型以及受这些投影影响的脑干回路的身份。 这些信息将为解释其他类型的研究结果提供解剖学基础，并最终帮助我们了解下行通路在正常大脑和患病或受损大脑中的作用。