FUNCTIONAL ANATOMY OF THE AUDITORY PATHWAYS

听觉系统由上行通路组成 从耳朵到大脑皮层的信息，在那里声音被感知， 从皮层下行的通路，调节处理， 上升的信息流。 下行通路在 各种功能，包括选择性注意，学习， 频率选择性、声音定位和语音识别 声音. 以前关于下行通路的许多工作都集中在 从脑干到耳蜗的投射 表征 细胞的形态学、生理学和递质化学， 一个耳蜗的研究项目使我们对耳蜗的理解 这个橄榄耳蜗系统。 我们对剩下的 下行途径，其中一些涉及更多的细胞技术 检查一些最大组件的功能组织 下行听觉通路的一部分 我们的实验集中在听觉皮层的投射上 脑干听觉核团 这条途径的重要性在于 最近的发现强调了大脑皮层的投射 比以前认为的更广泛，延伸到 耳蜗核，这是听觉信息进入的部位 进入大脑 我们实验的一个目标是确定 脑干回路与下行投射直接联系 大脑皮层 第二个目标是确定 五个上升到下降的细胞之间的关系 投射和听觉皮层的功能组织。 的 结果应该提供对信息类型的深入了解， 由下行投影传输的以及 脑干回路受到这些投射的影响。 这 这些信息将反过来为解释 其他类型研究的结果，最终帮助我们 了解下行通路在正常和 患病或受损的大脑。

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 pathway play a role in a 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 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 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 projects from the cortex. A second goal is to identify the anatomical relationships between the cells that five 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 diseased or damaged brain.