CENTRAL PROCESSING--NEURAL MECHANISMS OF SPATIAL HEARING

功能磁共振成像(FMRI)允许非 受试者脑功能的侵入性空间标测。 以前对听觉处理的功能磁共振研究大多集中在 并解决了认知问题，而非基础问题 神经生理学问题。我们最新的技术发展 使我们第一次能够想象声音引起的活动 在皮质下听觉结构中，特别是在下部 丘脑和内侧膝状体。考虑到目前的情况 FMRI的空间分辨率，我们预计其他皮质下 听觉核团也是可分辨的，包括耳蜗核。 细胞核和上橄榄复合体。因此，人类的听觉 功能现在可以从脑干映射到大脑皮层。武装的 通过此功能，我们将检查的功能组织 人类的听觉通路。丰富的动物数据已经 提供了大量关于 哺乳动物的中枢听觉系统，但也指出 物种间差异显著。我们的功能磁共振实验将 确定基本哺乳动物的基本成分是否 计划适用于人类。例如，我们将检查 个别皮质下结构的功能偏侧化 (例如，耳蜗核、上橄榄复合体、下橄榄复合体 丘脑、内侧膝状体)和频率 不同皮质区域的组织。如果预测基于 动物的工作是矛盾的，这将意味着电流 思考人类的听觉处理将需要 从根本上修改了。我们还将在患有以下疾病的受试者中使用功能磁共振成像 外周高频听力损失评估是否 功能重组发生在皮质水平，正如已经发生的那样 在动物电生理学文献中得到证实。这个 听觉皮质的根本重组的可能性 发生在外周损伤之后，具有深远的影响 通过助听器或人工耳蜗进行听力康复。 拟议的实验将提供关于 人类的听觉系统，这是无法通过其他方式获得的。这个 这些研究的结果将在以下方面取得重大进展 对中枢听觉正常和异常的认识 在人类身上起作用。

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.