Age related effects on macaque auditory cortex

描述（由申请人提供）： 听力障碍是老年人残疾的第三大原因。在美国，超过一半的70岁以上的人患有某种形式的与年龄有关的听力缺陷。这是一个普遍存在的问题，有许多来源，和周边贡献的年龄相关的缺陷，特别是高频听力损失，已被探索，并揭示了这些疾病的几个重要特征。然而，对于年龄相关性听力损失和正常衰老对中枢听觉结构（特别是新皮层）的影响，以及中枢结构中解剖学或生理学过程的年龄相关性变化如何导致感知缺陷，仍然知之甚少。我们对这些中枢效应缺乏了解，在很大程度上是因为缺乏一种有效的动物模型，这种动物模型（1）与人类具有许多听觉皮层的组织特征，（2）具有相当长的寿命，使得与年龄相关的听力障碍在几年的时间内发展，就像人类一样，（3）不是过于昂贵。我有一个独特的机会来开发这样一个动物模型，因为我有机会接触到一个大型的老年猕猴群体，这些猕猴满足这三个标准。这项研究的目的是确定哪些听觉皮层反应特性最受正常衰老和年龄相关性听力损失的影响。在这些实验中将使用两只正常的年轻动物、两只具有年龄相关的高频听力损失的老年动物和两只年龄匹配的没有年龄相关的听力损失的老年动物。将在每只猴中定义初级和次级听觉皮层场中单个神经元的光谱、空间和时间响应特性。将比较不同猴子的神经元之间的比较，以及由于高频听力损失而重组的听觉皮层区域，以确定听觉信息处理的哪些方面最容易受到衰老和与年龄相关的听力损失的影响。这项研究的结果将为未来的研究计划提供基础，这些研究计划旨在为患有与年龄相关的听力缺陷的个人开发补救治疗和疗法以及助听器设计。

DESCRIPTION (provided by applicant): Hearing deficits are the third leading cause of disability in the aged. Over half of all people in the US over seventy suffer some form of age-related hearing deficits. This is a ubiquitous problem with many sources, and the peripheral contributions to age-related deficits, particularly high frequency hearing loss, have been explored and have revealed several important features of these disorders. However, there remains relatively little understood about the consequences of age-related hearing loss and normal aging on central auditory structures, particularly the neocortex, and how age-related changes in either anatomical or physiological processes in central structures give rise to perceptual deficits. Our lack of understanding of these central effects is due in large part to the lack of an effective animal model that (1) shares many organizational features of auditory cortex with humans, (2) has a reasonably long life span such that age-related hearing deficits progress over the course of several years as in the human, and (3) are not prohibitively expensive. I have a unique opportunity to develop such an animal model as I have access to a large geriatric colony of macaque monkeys that satisfy these three criteria. The goals of this proposal are to determine which auditory cortical response properties are most influenced by normal aging and age-related hearing loss. Two normal young animals, two older animals with age- related high frequency hearing loss, and two older age-matched animals without age-related hearing loss will be used in these experiments. Spectral, spatial, and temporal response properties of single neurons in primary and secondary auditory cortical fields will be defined in each, monkey. Comparisons between neurons in different monkeys, as well as in auditory cortical fields that have been reorganized due to the high frequency hearing loss, will be compared to determine which aspects of auditory information processing are most susceptible to aging and age-related hearing loss. The results of this study will provide the foundation for future research programs aimed at the development of remedial treatments and therapies, as well as in hearing aid design, for individuals suffering from age-related hearing deficits.