Neural determinates of cortical plasticity with age and hearing loss

项目摘要/摘要 与年龄相关的听力损失是最常见的衰老慢性疾病之一，但人们对其原因知之甚少 大脑适应这种逐渐退化和丢失的输入，以及随后可听的重新引入 通过扩音器发出声音。这种神经适应，或可塑性，发生在对输入和 通过声学体验。在拟议的研究方案中，根据RFA-AG-18-017“Central 年龄相关性听力损失的神经机制，目标1中的实验表征了年龄和听力损失 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。实验的设计是为了确定活动之间的关系如何 听神经和听皮质随着年龄和听力损失的增加而变化，并通过识别 导致这些变化的潜在神经机制，特别是神经化学物质的变化 环境。建议的实验然后测试这些塑料变化对自我感知的影响程度。 听力障碍和语音识别，并被个人的声学经验改变。 目标2中的实验考察了年龄和听力损失对改变能力和适应能力的影响 经验，或经验驱动的可塑性，可以在几分钟内通过接触重复的 刺激以一种特定的方式呈现，表现为大脑对 暴露后的刺激。通过研究这种跨越听觉和视觉形态的可塑性， 拟议的实验旨在消除因年龄增长而产生的影响，以及 特定于听觉系统的变化。类似于动态平衡可塑性，我们将考察 体验驱动的可塑性中的哪些个体差异源于潜在的 神经化学环境。我们将整合不同目标的结果，以确定体内平衡之间的关系 以及经验驱动的可塑性，以及年龄的增长和听力损失是如何推动这些关系的。一个 我们对随着年龄和年龄的增长而发生的塑料变化的理解有了显著的进步 听力损失是必要的，这样才能在康复过程中利用整形工艺来实现最大的益处。 此外，我们评估神经化学环境对人类皮质可塑性的贡献的能力 可提供特定的干预目标，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.