Contribution of a corticofugal pathway to auditory perception

摘要 听觉感知由自下而上(前馈)和自上而下(反馈或皮质分离)两种方式调节。 机械装置。自上而下的机制过滤上升的自下而上的流，这改善了听觉 通过增强神经元对行为相关刺激的表征来感知，同时 抑制行为无关刺激的神经元表征。作为这种互动的结果 在自下而上和自上而下的机制之间，听者可以灵活地引导他们的知觉和认知 在追求目标导向行为方面的资源。然而，尽管它们至关重要，但我们并没有完全 了解皮质分离活动对听觉的贡献，特别是在灵长类动物模型中 听证。这个R21建议通过确定皮质丘脑的贡献来填补这一知识空白 到灵长类听觉的通路(即从初级听觉皮质到听觉丘脑的通路) 感知力。我们通过研究皮质丘脑通路对听觉的影响来确定它对听觉的贡献。 功能连接是在猴子执行与神经行为学相关的任务时受到调节的， “合唱发声”任务。在这个合唱发声的任务中，猴子们偷偷地听两个声音之一 说话者的位置，并检测嵌入在发声的背景“合唱”中的“目标”发声； 目标发声可能会或可能不会出现在所关注的位置。我们操控听力 通过(1)改变目标发声相对于背景合唱的声级以及(2) 改变猴子空间注意力的轨迹。我们有三个假设。我们假设与任务相关的 在低信噪比条件下，交流至MGB功能连接的变化将增加。我们还假设 当猴子注意到目标发声的位置时，这种功能连接会增加 而不是当他们不这样做时。最后，我们假设AC到MGB功能连接中与任务相关的变化 将大于交流和非词法MGB组件之间的MGB 组件。无论是个人还是集体，本提案的调查结果都提供了有价值的量化见解 大脑皮质丘脑回路在灵长类听觉行为中的作用。

SUMMARY Auditory perception is mediated by both bottom-up (feedforward) and top-down (feedback or corticofugal) mechanisms. Top-down mechanisms filter the ascending bottom-up stream, which improves auditory perception by enhancing the neuronal representations of behaviorally relevant stimuli, while simultaneously suppressing neuronal representations of behaviorally irrelevant stimuli. As a consequence of this interaction between bottom-up and top-down mechanisms, a listener can flexibly direct their perceptual and cognitive resources in the pursuit of goal-directed behavior. Yet, despite their critical importance, we do not fully understand the contribution of corticofugal activity to auditory perception, especially in primate models of hearing. This R21 proposal begins to fill this knowledge gap by identifying a contribution of a corticothalamic pathway (i.e., a pathway from the primary auditory cortex to the auditory thalamus) to primate auditory perception. We identify contributions of a corticothalamic pathway to auditory perception by examining how its functional connectivity is modulated during a monkey's performance on a neuroethologically relevant task, the “vocalization-in-chorus” task. In this vocalization-in-chorus task, monkeys covertly attend to one of two speakers' locations and detect a “target” vocalization that is embedded in a background “chorus” of vocalizations; the target vocalization may or may not be presented at the attended location. We manipulate the listening environment by (1) changing the sound level of the target vocalization relative to the background chorus and (2) changing the locus of the monkeys' spatial attention. We have three hypotheses. We hypothesize that task-related changes in AC-to-MGB functional connectivity will increase in low signal-to-noise regimes. We also hypothesize that this functional connectivity will increase when the monkey attends to the location of the target vocalization than when they do not. Finally, we hypothesize that task-related changes in AC-to-MGB functional connectivity will be greater between AC and lemniscal components of the MGB than between AC and non-lemniscal MGB components. Individually and collectively, the findings of this proposal provide valuable, quantitative insights into the role of corticothalamic circuits in primate auditory behavior.