CENTRAL PROCESSING--NEURAL MECHANISMS OF SPATIAL HEARING

功能性磁共振成像（fMRI）允许非 人类受试者脑功能的侵入性空间映射。 大多数以前的听觉处理功能磁共振成像研究都集中在 在大脑皮层上，并解决了认知，而不是基本的 神经生理问题。 我们最近的技术发展 让我们第一次想象出声音引起的活动 皮层下听觉结构，特别是下皮层 丘和内侧膝状体。 鉴于目前的 空间分辨率的功能磁共振成像，我们预计其他皮层下 听觉核团也是可以分辨的，包括耳蜗 核和上级橄榄复合体。 因此，人类听觉 功能现在可以从脑干映射到皮层。 武装 有了这种能力，我们将研究 人类的听觉通路 大量的动物数据 提供了大量关于该组织的资料， 哺乳动物的中枢听觉系统，但也指出， 物种间的显著差异。 我们的功能磁共振成像实验 确定基本哺乳动物的基本组成部分 计划适用于人类。 例如，我们将检查 个别皮质下结构功能的偏侧化 (e.g.,耳蜗上级橄榄复合体下核 丘，内侧膝状体），和频率 不同皮层区域的组织。 如果预测基于 动物工作是矛盾，这将意味着目前 思考人类的听觉处理需要 从根本上进行了修订。 我们还将使用功能磁共振成像在受试者 外周高频听力损失评估是否 功能重组发生在皮层水平，如 在动物电生理学文献中得到证实。 的 听觉皮层的基本重组 发生在外周损伤之后， 通过助听器或人工耳蜗进行听觉康复。 拟议的实验将提供有关 人类听觉系统，这是无法通过其他方式获得的。 的 这些研究的结果将构成一个重大进展， 关于正常和异常中枢听觉的知识 在人类中的功能。

Functional magnetic resonance imaging (fMRI) allows non- invasive spatial mapping of brain function in human subjects. Most previous fMRI studies of auditory processing have focussed on the cortex and have addressed cognitive, rather than basic neurophysiological issues. Our recent technical developments have allowed us to image, for the first time, sound-evoked activity in subcortical auditory structures, specifically the inferior colliculus and the medial geniculate body. Given the current spatial resolution of fMRI, we anticipate that other subcortical auditory nuclei will also be resolvable, including the cochlear nucleus and superior olivary complex. Thus, human auditory function can now be mapped from brainstem to cortex. Armed with this capability, we will examine the functional organization of the human auditory pathway. A wealth of animal data has provided considerable information about the organization of the mammalian central auditory system, but has also pointed out significant inter-species differences. Our fMRI experiments will establish whether fundamental components of the basic mammalian plan are applicable to the human. For example, we will examine the lateralization of function in individual subcortical structures (e.g., cochlear nucleus, superior olivary complex, inferior colliculus, medial geniculate body), and the frequency organization of different cortical areas. If predictions based on the animal work are contradicted, it will mean that current thinking about human auditory processing will need to be fundamentally revised. We will also use fMRI in subjects with peripheral high-frequency hearing loss to evaluate whether functional reorganization occurs at cortical levels, as has been demonstrated in the animal electrophysiology literature. The possibility that fundamental reorganization of auditory cortex occur subsequent to peripheral damage has profound implications for auditory rehabilitation via hearing aids or cochlear implants. The proposed experiments will provide information about the human auditory system which is obtainable in no other way. The results of these studies will constitute a significant advance in knowledge about both normal and abnormal central auditory function in humans.