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

项目总结 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 人口动态。由感觉刺激引起的大脑振荡是场电位的波动，反映了 由给定刺激驱动的神经群体的综合活动。已经观察到了 从无脊椎动物到灵长类动物的许多物种，并参与了各种过程，如注意力和 感知门控。谷仓猫头鹰是几十年来研究声音定位的专家。他们的井- 所描述的中脑刺激选择网络，致力于定位显著声音的电路，提供了 独一无二的机会来评估大脑振荡在编码中的作用。猫头鹰之前的活体记录 视顶盖(OT)，哺乳动物上丘的同系物，已经表明伽玛振荡(25-140) 赫兹)被调谐到视觉和听觉空间。然而，之前在中脑深层结构中的录音， 像OT一样，都是依靠单电极和光镇静。这些技术限制阻碍了我们的 了解在给定时间振荡可能如何在空间地图上传播，并强调 注意力和知觉等唤醒过程的概括性问题。我们的实验室开创了人类的先河 使用多电极阵列在空间地图上进行记录，最近开发了慢性微驱动器 在清醒的猫头鹰身上植入录音。有了这些技术成就，我们将解决几个公开的问题 关于振荡在感知显著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了尖峰图案 到优先阶段。初步分析表明，首选方向的声音刺激会增加功率。 在伽马范围内以聚焦的方式，支持由大脑驱动的棘波模式的假说 振荡对声音位置有编码作用。目标2将比较觉醒和唤醒的振荡特性 麻醉状态。初步数据和分析表明，虽然清醒时伽马能量更高 状态，尖峰对伽马振荡的相位锁定在各个状态下是一致的，这表明 在麻醉过程中，伽玛振荡在组织棘波模式中的功能效应被保留下来。在AIM 3，我们将在觉醒的猫头鹰的听觉丘脑和OT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起作用的假说。我们会 配对声音定向行为，如转头和扩瞳反应，与电生理学 阐明知觉过程中区域间信号传递的编码机制。了解如何将 猫头鹰的中脑刺激选择电路利用振荡进行自下而上的接力和刺激选择 可以洞察人类听力中的类似过程，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，并可能为小说提供信息 助听器的优化策略。

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.