Neural determinates of cortical plasticity with age and hearing loss

项目总结/摘要 听力损失是老年人最常见的慢性疾病之一，但人们对听力损失是如何发生的知之甚少。 大脑适应了这种输入的逐渐退化和损失，以及随后的听觉重新引入， 声音通过放大。这种神经适应或可塑性是对输入丢失的反应， 通过声学体验。在拟定的研究计划中，响应RFA-AG-18-017“中央 听力损失的神经机制，目标1中的实验表征年龄和听力损失 对稳态可塑性的影响，或皮质神经元调节其兴奋性的程度， 传入的神经活动实验的目的是确定活动之间的关系， 听觉神经和听觉皮层随着年龄的增长和听力损失而变化， 导致这些变化的潜在神经机制，特别是神经化学物质 环境然后，实验将测试这些可塑性变化对自我感知的影响程度 听力障碍和语音识别的影响，并通过个人的声学经验改变。 目标2中的实验研究了年龄和听力损失对改变和适应能力的影响， 经验，或经验驱动的可塑性，这可以在几分钟内通过暴露于重复的 刺激以特定的方式呈现，并表现为大脑对刺激的反应增强。 暴露后刺激。通过检查这种类型的可塑性在听觉和视觉模态， 拟议的实验旨在消除由于年龄增长和那些 特别是听觉系统的变化与稳态可塑性类似，我们将研究 经验驱动的可塑性的个体差异来自于潜在的 神经化学环境我们将整合不同目标的结果，以确定稳态之间的关系。 和经验驱动的可塑性，以及年龄增长和听力损失如何推动这些关系。一 我们对随着年龄增长而发生的塑料变化的理解有了重大进展， 听力损失是需要的，以便可以利用塑性加工以在康复期间获得最大的益处。 此外，我们评估神经化学环境对人类皮层可塑性的贡献的能力 可以提供具体的干预目标，以提高康复期间的适应能力。

PROJECT SUMMARY/ABSTRACT Age-related hearing loss is one of the most common chronic conditions of aging, yet little is known about how the brain adapts to this gradual degradation and loss of input and the subsequent reintroduction of audible sound through amplification. This neural adaptation, or plasticity, occurs in response to a loss of input and through acoustic experiences. In the proposed research program, in response to RFA-AG-18-017 “Central Neural Mechanisms of Age-Related Hearing Loss, the experiments in Aim 1 characterize age and hearing loss effects on homeostatic plasticity, or the degree to which cortical neurons regulate their excitability relative to incoming neural activity. Experiments are designed to identify how relationships between activity in the auditory nerve and auditory cortex change with increasing age and hearing loss and by identifying the underlying neural mechanisms contributing to these changes, specifically changes in the neurochemical environment. Proposed experiments then test the extent to which these plastic changes effect self-perception of hearing handicap and speech recognition, and are altered by an individual's acoustic experiences. Experiments in Aim 2 examine age and hearing loss effects on the capacity for change and adaptation with experience, or experience-driven plasticity, which can be induced in minutes through exposure to a repetitive stimulus presented in a specific manner, and is manifested as an enhancement in the brain's response to the stimulus post-exposure. By examining this type of plasticity across auditory and visual modalities, the proposed experiments are designed to disambiguate effects attributed to increasing age and those that are specific to changes in the auditory system. Similar to homeostatic plasticity, we will examine the extent to which individual differences in experience-driven plasticity arise from differences in the underlying neurochemical environment. We will integrate results across aims to identify relationships among homeostatic and experience-driven plasticity, and how increasing age and hearing loss drive these relationships. A significant advancement in our understanding of the plastic changes that occur with increasing age and hearing loss is needed so that plastic processes can be utilized to allow maximal benefit during rehabilitation. Moreover, our ability to assess the contribution of the neurochemical environment to human cortical plasticity may provide specific targets for intervention to enhance adaption during rehabilitation.