Auditory-based navigation: attentional shifts rapidly modulate hippocampal codes

项目摘要/摘要 海马体，一种与空间记忆和导航有关的大脑结构，在这个过程中显示出变化 衰老、精神疾病、神经紊乱和神经退行性疾病。海马区功能障碍 会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……里面 健康的受试者、空间注意力和导航是紧密相连的，因为绘制环境地图需要 注意自己周围的环境。此外，在导航时，人类和其他动物会交换注意力 在两个互补的坐标系之间：以世界为中心的参考系，用于监测绝对坐标系 以及用于监测相对于障碍物的相对位置的以自我为中心的参照系， 共同的细节和目标。人们对神经动力学知之甚少，而神经动力学正是这种注意力快速转移的基础 伴随着这些参考帧之间的切换-主要是因为可靠的空间指示器 在标准的动物模型中缺乏关注。这项拟议的研究通过利用蝙蝠来弥合这一差距， 一种在导航时主动控制其回声定位信号以关注物体的哺乳动物--与许多 盲人使用自己发出的声音(舌头点击和手杖敲击)的回声来定位物体 在室内和室外导航。蝙蝠和人类盲人回声定位器都使用它们的 声纳，产生一个“声学手电筒”--它提供了它们瞬间空间的直接度量 请注意。拟议中的实验将在无线记录的同时跟踪公开的空间注意力转移 研究注意对海马神经元神经活动的影响。需要检验的假设是，公开的 空间注意通过锐化空间表征和通过 在以世界为中心和以自我为中心的坐标系之间切换海马体编码。要做到这一点，动物 将在两种情况下导航：(1)静止和可预测的环境，在那里动物可以直接注意 固定对象，注意要求相对较低；和(2)不可预测的环境， 移动特定对象和目标，其中注意力要求很高，动物迅速将注意力转移到 检查动态对象。这些可预测和不可预测的情况将在两个不同的 实验装置：一个三维多媒体测试室，动物在其中缓慢导航，以及一个200- 米，动物高速移动的一维隧道。因为回声定位提供了强大的 这项研究是显性空间注意力的明确指标，将产生对注意力驱动的变革性见解 自然主义行为中的海马区动力学。这些发现将为神经缺陷提供新的见解 在空间导航和记忆方面，产生技术进步的设计轻量化、小型化 用于监测患者健康的辅助医疗设备，将为听觉的神经基础提供新的线索 盲人的注意力和听觉导航。

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.