Corticofugal Control of Central Auditory Sensitivity

IBN-9604238 PI：JEN在感官信号处理过程中，大脑具有编辑和调整到达它的信息流的内置能力。众所周知，大脑皮层有神经通路，称为皮质分离通路，这些通路下行影响神经活动，通过上升感觉通路将信息传递到皮质。我们对这些下行通路如何以及何时施加影响知之甚少，但在听觉系统中，它们被认为在模式识别和声信号定位等功能中发挥着重要作用。这个项目使用一种生理学方法来确定皮质下行通路如何影响中脑听觉结构中称为上丘的单个听觉神经细胞的反应活动。电生理记录将检测皮质对这些神经元的强度编码、频率调谐和听觉空间敏感性的调节。这个系统可能是一种让大脑在嘈杂环境中将注意力集中在重要但微弱的听觉信号上的方法，例如在回声定位行为中。这项工作的结果将对开发更现实和动态的中枢听觉处理模型具有重要意义。它还将加深我们对大脑对信号处理的主动调节的理解，因此将对理解其他感官系统以及神经行为学、动物行为和生物工程(包括开发助听器)具有潜在的影响。

IBN-9604238 PI: Jen During sensory signal processing, the brain has the built-in ability to edit and adjust the flow of information that reaches it. It is known that the cortex has neural pathways, called corticofugal pathways, that descend to influence the neural activity carrying information coming up to the cortex by the ascending sensory pathways. We know very little about how and when these descending pathways exert their influence, but in the auditory system they are believed to be important in functions such as pattern recognition and localization of acoustic signals. This project uses a physiological approach to determine how descending cortical pathways can affect the response activity of single auditory nerve cells in a midbrain auditory structure called the superior colliculus. Electrophysiological recordings will examine corticofugal regulation of intensity coding, frequency tuning, and auditory spatial sensitivity of these neurons. This system may be a way for the brain to 'focus in' on important but faint auditory signals in a noisy environment, for example in echolocation behavior. Results from this work will be important for developing a more realistic and dynamic model of central auditory processing. It also will enhance our understanding of active regulation of signal processing by the brain, and so will have a potential impact on understanding other sensory systems, as well as on fields such as neuroethology, animal behavior, and on bioengineering including development of aids for hearing.