Role of brain oscillations in midbrain and forebrain networks supporting stimulus selection in the sound localization pathway of barn owls

项目摘要 现代神经科学面临的挑战是将我们对单细胞活动模式的理解与大细胞活动模式的理解联系起来。 种群动态由感觉刺激诱发的脑振荡是场电位的波动， 由给定刺激驱动的神经群体的组合活动。观察到的振荡， 从无脊椎动物到灵长类动物的许多物种，并涉及各种过程，如注意力和 知觉门控仓鸮是声音定位专家，研究了几十年。他们的好- 所描述的中脑刺激选择网络，一种专用于定位突出声音的电路，提供了一种 独特的机会来评估大脑振荡在编码中的作用。之前在猫头鹰体内的记录 视顶盖（OT），哺乳动物上级丘的同源物，已经表明伽马振荡（25-140 Hz）被调谐到视觉和听觉空间。然而，先前在中脑深部结构中的记录， 像OT一样，依赖于单电极和光稳定。这些技术限制阻碍了我们 了解振荡如何在给定的时间在空间地图上传播，并强调 问题的普遍性，以唤醒过程，如注意力和知觉。我们的实验室开创了 使用多电极阵列记录整个空间地图，最近开发了慢性微驱动器 在清醒的猫头鹰身上植入录音有了这些技术成果，我们将解决几个开放的问题。 关于振荡在感知显着刺激和刺激选择中的作用的问题。目标1将 评估伽马振荡的空间范围，并确定振荡是否组织尖峰模式 优选的阶段。初步分析表明，声音刺激的首选方向增加功率 在伽玛范围内的焦点方式，支持的假设，尖峰图案驱动的大脑 振荡在编码声音位置中起作用。目标2将比较清醒和清醒状态下的振荡特性， 麻醉状态初步的数据和分析表明，虽然伽马功率在清醒时较高， 状态，尖峰到伽马振荡的锁相在状态之间是一致的，这表明 在麻醉过程中保持了γ振荡在组织尖峰图形中的功能作用。在Aim中 3.我们将在清醒行为的猫头鹰的听觉丘脑和OT中进行同步记录，以测试 伽马振荡在感知显著声音和刺激选择中发挥作用的假设。我们将 将声音定向行为（如头部转动和瞳孔扩张反应）与电生理学配对， 阐明编码机制的区域间信号在感知。了解如何 猫头鹰的中脑刺激选择电路利用振荡进行自下而上的中继和刺激选择 可以提供对人类听觉中类似过程的洞察，其中最相关的听觉流必须是 在听觉场景复杂（鸡尾酒会效应）的情况下优先考虑，并可能告知小说 助听器的选配

PROJECT SUMMARY Modern neuroscience faces the challenge of bridging our understanding of single cell activity patterns to large population dynamics. Brain oscillations evoked by sensory stimuli are fluctuations in field potentials reflecting the combined activity of neural populations driven by a given stimulus. Oscillations have been observed in many species from invertebrates to primates, and have been implicated in various processes like attention and perceptual gating. Barn owls are specialists in sound localization studied for several decades. Their well- described midbrain stimulus selection network, a circuit dedicated to localizing salient sounds, provides a unique opportunity to evaluate the role of brain oscillations in coding. Previous in vivo recordings in the owl’s optic tectum (OT), homolog of the mammalian superior colliculus, have shown that gamma oscillations (25-140 Hz) are tuned to both visual and auditory space. However, previous recordings in deep midbrain structures, like OT, have relied on single electrodes and light tranquilization. These technical limitations impede our understanding of how oscillations may spread across the space map at a given time, and underscores the question of generalizability to awake processes like attention and perception. Our lab has pioneered population recordings across the space map using multielectrode arrays, and has recently developed chronic microdrive implants for recordings in awake owls. With these technical achievements, we will address several open questions regarding the role of oscillations in perception of salient stimuli and stimulus selection. Aim 1 will evaluate the spatial extent of gamma oscillations, and determine whether oscillations organize spike patterning to preferred phases. Initial analyses show that sound stimulation with the preferred direction increases power within the gamma range in a focal manner, supporting the hypothesis that spike patterning driven by brain oscillations has a role in coding sound location. Aim 2 will compare oscillation properties across awake and anesthetized states. Preliminary data and analysis suggest that while gamma power is higher in the awake state, phase locking of spikes to gamma oscillations is consistent across states, suggesting significant functional effects of gamma oscillations in organizing spike patterning are preserved during anesthesia. In Aim 3, we will conduct simultaneous recordings in the auditory thalamus and OT in awake behaving owls to test the hypothesis that gamma oscillations play a role in perception of salient sounds and stimulus selection. We will pair sound orienting behaviors, such as head turning and pupillary dilation responses, with electrophysiology to elucidate the coding mechanisms underlying interregional signaling during perception. Understanding how the owl’s midbrain stimulus selection circuit utilizes oscillations to conduct bottom-up relay and stimulus selection can provide insight to similar processes in human audition where the most relevant auditory stream must be prioritized in circumstances when the auditory scene is complex (cocktail party effect), and may inform novel optimization strategies for hearing aids.