Corticofugal contributions to auditory perceptual learning

项目摘要 练习可以提高听觉刺激的检测或辨别能力。这个过程，叫做知觉 学习，促进语言习得和音乐技能的发展，并提高演讲 听力障碍者的理解。以前的研究强调了听觉皮层的重要性 在听觉感知学习中，我们对神经回路机制缺乏完整的了解。 从听觉皮层到皮层下听觉区的离皮层投射包括一个巨大的下行投射， 通路这条通路整合了非感觉输入，这对感知学习至关重要， 在皮层下的听觉区域中，神经元对相关刺激的反应更加敏锐。灭活本 离皮质途径还损害在具有困难的、近阈值刺激的感觉任务中的学习。综合起来看， 现有的证据表明，离皮质投射是很好的定位发挥重要作用， 知觉学习这一提议的核心假设是知觉训练强化了 在上行听觉通路中对活动的离皮质调节，导致逐渐增强 在信号检测中作为感知学习的基础。目标1将在自由移动中使用体内电生理学， 行为动物，以确定是否有学习相关的变化，在皮层下的神经活动， 听觉区目的2将研究离皮质投射是否是采集和/或 维持训练引起的感知灵敏度的改善。AIM 3将使用投影专用光纤 光度测定记录，以评估离皮质神经元的活动是否与行为改善相关 在知觉学习中。从拟议的实验中得到的发现将揭示神经回路 潜在的听觉感知学习，并可能最终为改善听觉感知的策略提供信息， 临床人群。

PROJECT SUMMARY Practice can improve the detection or discrimination of auditory stimuli. This process, called perceptual learning, facilitates language acquisition and the development of musical skills, and improves speech understanding in the hearing-impaired. Previous studies have highlighted the importance of the auditory cortex in auditory perceptual learning, but we lack a complete understanding of the neural circuit mechanisms involved. Corticofugal projections from the auditory cortex to subcortical auditory regions comprise a massive descending pathway. This pathway integrates non-sensory inputs, which are essential to perceptual learning, with sensory information and sharpens neural responses to relevant stimuli in subcortical auditory regions. Inactivation of this corticofugal pathway also impairs learning in sensory tasks with difficult, near-threshold stimuli. Taken together, the existing evidence suggests that corticofugal projections are well-positioned to play an important role in perceptual learning. The core hypothesis of this proposal is that perceptual training strengthens corticofugal modulation of activity in the ascending auditory pathway, leading to gradual enhancements in signal detection that underlie perceptual learning. Aim 1 will use in vivo electrophysiology in freely-moving, behaving animals to determine whether there are learning-related changes in neural activity in subcortical auditory regions. Aim 2 will investigate whether corticofugal projections are necessary for the acquisition and/or maintenance of training-induced improvements in perceptual sensitivity. Aim 3 will use projection-specific fiber photometry recordings to assess if the activity of corticofugal neurons correlates with behavioral improvements during perceptual learning. The findings from the proposed experiments will shed light on the neural circuits underlying auditory perceptual learning and may ultimately inform strategies to improve auditory perception in clinical populations.