Auditory-based navigation: attentional shifts rapidly modulate hippocampal codes

项目总结/摘要 海马体是一种与空间记忆和导航有关的大脑结构， 衰老、精神疾病、神经系统疾病和神经退行性疾病。海马功能障碍 引起不同的临床症状，其中许多与注意力和导航障碍有关。在 健康的受试者，空间注意力和导航是紧密联系在一起的，因为绘制环境需要 注意周围的环境。此外，在导航时，人类和其他动物会切换注意力， 在两个互补坐标系之间：一个以世界为中心的参考框架，用于监测绝对 位置，以及用于监测相对于障碍物的相对位置的自我中心参考系， 同类和目标。我们对神经动力学知之甚少，神经动力学是注意力快速转移的基础， 伴随着这些参考框架之间的转换，主要是因为空间的可靠指标 在标准动物模型中缺乏关注。这项拟议中的研究通过利用蝙蝠弥合了这一差距， 一种哺乳动物，在导航时主动控制其回声定位信号来关注物体-类似于许多 盲人使用自己产生的声音（舌头点击和手杖敲击）的回声来定位物体 并在室内和室外导航。蝙蝠和人类的盲人回声定位器都是用它们的 声纳，产生一个“声音闪光灯”-这提供了一个直接的度量，他们的时刻到时刻的空间 关注拟议中的实验将跟踪明显的空间注意力转移，同时无线记录 海马神经元来研究注意力对神经活动的影响。有待检验的假设是， 空间注意通过锐化空间表征和 在世界中心和自我中心的坐标框架之间切换海马编码。为此，动物 我将在两种情况下导航：（1）一个固定的和可预测的环境，动物直接注意 固定的物体，注意力需求相对较低;（2）不可预测的环境， 移动同种和目标，注意力要求高，动物迅速转移注意力， 检查动态对象。这些可预测和不可预测的条件将在两个不同的研究 实验设置：一个三维多媒体测试室，动物缓慢导航，和一个200- 一米长的一维隧道，动物在那里高速移动。因为回声定位提供了一个强大的 显性空间注意力的明确指标，这项研究将产生变革性的见解注意力驱动 自然行为中的海马动力学这些发现将为神经缺陷提供新的见解 在空间导航和记忆，产量技术进步的设计重量轻，小型化， 用于监测患者健康的辅助医疗设备，并将为听觉神经基础提供新的见解 盲人的注意力和导航能力。

Project Summary/Abstract The hippocampus, a brain structure implicated in spatial memory and navigation, show changes in the course of aging, mental illnesses, neurological disorders, and neurodegenerative diseases. Hippocampal dysfunctions give rise to diverse clinical symptoms, many of which are tied to impairments in attention and navigation. In healthy subjects, spatial attention and navigation are tightly linked, because mapping the environment requires attention to one’s surroundings. Furthermore, while navigating, humans and other animals switch attention between two complementary coordinate systems: a world-centered reference frame for monitoring absolute position, and an egocentric reference frame for monitoring relative position with respect to obstacles, conspecifics, and targets. Little is known about neural dynamics that underlie the rapid shifts in attention that accompany switches between these reference frames—primarily because reliable indicators of spatial attention are lacking in standard animal models. The proposed research bridges this gap by exploiting the bat, a mammal that actively controls its echolocation signals to attend to objects while navigating—similar to many blind humans who use echoes from self-produced sounds (tongue clicks and cane tapping) to localize objects and navigate indoors and outdoors. Both bats and human blind echolocators attend to objects using their sonar, generating an ‘acoustic flashlight’—which provides a direct metric of their moment-to-moment spatial attention. The proposed experiments will track overt spatial attentional shifts while wirelessly recording hippocampal neurons to study attentional effects on neural activity. The hypothesis to be tested is that overt spatial attention rapidly modulates hippocampal spatial codes, by sharpening spatial representation and by switching hippocampal coding between world-centered and egocentric coordinate frames. To do so, animals will navigate under two conditions: (1) a stationary and predictable environment where animals direct attention to fixed objects, and where attentional demands are relatively low; and (2) an unpredictable environment with moving conspecifics and targets, where attentional demands are high and animals shift attention rapidly to inspect dynamic objects. These predictable and unpredictable conditions will be studied in two different experimental setups: a three-dimensional multimedia test room where animals navigate slowly, and a 200- meter, one-dimensional tunnel where animals travel at high speeds. Because echolocation provides a powerful explicit indicator of overt spatial attention, this research will yield transformative insights into attention-driven hippocampal dynamics during naturalistic behavior. The findings will offer new insights into neurological deficits in spatial navigation and memory, yield technological advances in the design of lightweight, miniaturized assistive medical devices used to monitor patient health, and will shed new light on the neural basis of auditory attention and auditory-based navigation in blind humans.