NEUROIMAGING, AUDIOLOGY, PSYCHOACOUSTICS

该项目的第一个任务是招募所需的人类科目 计划项目。第二个是从听觉角度来描述 正常青年和老年人群的代表性样本 听力和听力损失谁将接受对比实验 心理声学、诱发电位、反射行为和正电子发射 体层摄影术。第三个目标是评估与年龄相关的变化 时间处理的心理物理学，噪声中的信号处理， 以及人类的双耳处理。最初的缺口检测研究已经 老年人听觉时间处理的年龄相关性减慢 成人外周敏感度基本正常。此外，我们还展示了 处理速度会不成比例地降低，因为 刺激配置增加。这表明与年龄相关的 改变发生在整个中枢听神经的多个部位 系统和额外的，不成比例的大的，在 处理将显示与双耳处理是必需的。我们的 第四个目标是利用正电子发射断层扫描(PET) 研究中枢听觉发生的功能变化 系统老化和老年性耳聋的结果。我们提出了一个详细的系列 一系列实验来区分衰老和高频的影响 感音神经性耳聋(SNHL)。此外，我们计划调查 异常快速响度发育的功能神经解剖学研究 (“招募”)和异常声音定位，这两种损害是 与年龄和SNHL有关。我们将通过确定 外音强度与外音程度之间的关系 听觉皮质的激活以及这种关系是如何受 年龄和与年龄相关的SNHL。我们将继续追问-- 频率SNHL影响老年受试者的皮层频率-位置图。 我们将进行实验，以确定双耳声音提示如何 参与声音定位的是由大脑皮层处理的 确定老化和高频SNHL对双耳的影响 正在处理。

The first task of this project is to recruit human subjects required for the Program Project. The second is to audiologically characterize representative samples of human of young and old subjects with normal hearing and hearing losses who will undergo comparative experiments in psychoacoustics, evoked potentials, reflex behavior, and positron emission tomography. The third aim is to evaluate age-related changes in the psychophysics of temporal processing, the processing of signal in noise, and binaural processing in humans. Initial gap detection studies have demonstrated age-related slowing in auditory temporal processing in older adults with essentially normal peripheral sensitivity. Also, we have shown that processing speed decreases disproportionately as the complexity of the stimulus configuration increases. This suggests that age-related changes occur at multiple sites throughout the central auditory nervous system and that additional, disproportionately large, decrements in processing will be revealed with binaural processing is required. Our fourth aim is to utilize Positron Emission Tomography (PET)) to investigate the functional changes that occur in the central auditory system as a result of aging and presbycusis. We propose a detailed series of experiments to separate the effects of aging from high-frequency sensorineural hearing loss (SNHL). In addition, we plan to investigate the functional neuroanatomy of abnormally rapid loudness growth ("recruitment") and abnormal sound localization, two impairments which are associated with age and SNHL. We will do so by determining the relationship between the intensity of an external tone and the degree of activation in the auditory cortex and how this relationship is affected by aging and by age-related SNHL. We will pursue the question of how high- frequency SNHL affects the cortical frequency-place map in old subjects. And we will conduct experiments to determine how binaural sound cues involved in sound localization are processed by the cerebral cortex and to determine the effect aging and high-frequency SNHL have on binaural processing.