Vestibular contribution to the encoding of object orientation relative to gravity

前庭对相对于重力的物体方向编码的贡献

• 批准号: 9174035
• 负责人: Ari Rosenberg
• 金额: $ 15.3万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9174035
• 关键词: Anatomy; Animal Experiments; Anterior; Applications Grants; Area; Basic Science; Bilateral; Biological Neural Networks; Brain; Brain Injuries; Cells; Clinical; Clinical Research; Clinical Treatment; Code; Cues; Darkness; Development; Disease; Disorientation; Ear; Electric Stimulation; Environment; Eye; Force of Gravity; Foundations; Future; Gravitation; Head; Homologous Gene; Human; Impairment; Individual Differences; Knowledge; Learning; Left; Lesion; Macaca; Measures; Monkeys; Motor; Nervous system structure; Neural Network Simulation; Neurons; Parietal; Patients; Perception; Photic Stimulation; Physiological; Planet Earth; Play; Population; Posture; Psychophysics; Reference Values; Reporting; Research; Residual state; Retinal; Role; Sensory; Shapes; Signal Transduction; Space Perception; Stimulus; Surface; Symptoms; System; Testing; Time; Visual; Visual Cortex; Work; base; experience; experimental study; extrastriate visual cortex; eye center; labyrinthectomy; neurophysiology; novel; novel strategies; orientation selectivity; public health relevance; relating to nervous system; research study; response; theories; vector; vertical perception; visual adaptation; visual-vestibular

DESCRIPTION (provided by applicant): Gravity plays a critical role in shaping our experience of the world, influencing both sensory perception and motor planning at fundamental levels. Understanding how vestibular information, that signals the orientation of the self relative to gravity, can be used to create a stable gravity-centered representation of the visual scene is thus important for understanding perception and action. Surprisingly little is known about where and how the brain may use a vestibular estimate of gravity to transform visual signals first encoded in eye-centered (retinal) coordinates into the gravity-centered representation we perceive. The proposed experiments aim to eliminate this knowledge gap. Two lines of research suggest two probable loci. The first is the caudal intraparietal area (CIP) which is known to encode a high-level visual representation of object orientation. The second is the visual posterior sylvian (VPS) which is known to respond to both vestibular and visual stimulation, and which clinical reports suggest may be involved in creating a gravity-centered visual representation. I hypothesize that the transformation occurs progressively, beginning with an egocentric representation in V3A (CIP's main visual input) and culminating in a primarily gravity-centered representation: V3A (egocentric) � CIP � VPS (mostly gravity-centered). It is thus expected that V3A represents object orientation in strictly egocentric (head and/or eye) coordinates, and that the computations implementing the transformation occur at the level of CIP and/or VPS. In Aim 1, the visual orientation selectivity of single neurons will be recorded with the monkey in multiple spatial orientations (rolled left/right ear down). This experiment dissociates egocentric (eye/head) from gravity- centered representations, allowing the reference frame in which single neurons encode object orientation to be determined. Even if the transformation to a gravity-centered representation is incomplete at the level of single cells in CIP and/or VPS, it is hypothesized that population activity in these areas can represent object orientation relative to gravity. This will be tested using neural network modeling and the framework of probabilistic population codes to develop a neural theory of how a gravity-centered representation of object orientation is achieved. In Aim 2, the role of the vestibular system in implementing this transformation will be tested directly by performing a bilateral labyrinthectomy and repeating experiments from Aim 1. Since electrical stimulation of vestibular afferents can change perceived visual object orientation, the elimination of vestibular signals is expected to profoundly, if not completely, abolish gravity's effects on visual responses. Any residual effect will be attributed to proprioceptive signals (not vision, since no visual cues to gravity will be present). After the lesion, the effect of gravity on visual responses may increase with time, suggesting a re-learning period in which the role of proprioceptive signals increases. This research is important for understanding vestibular-visual interactions and establishing novel directions for both basic and clinical research studies.

描述（由申请人提供）：重力在塑造我们对世界的体验中起着至关重要的作用，在基本层面上影响着感觉知觉和运动规划。因此，了解前庭信息（即自我相对于重力的方向信号）如何用于创建以重力为中心的视觉场景的稳定呈现，对于理解感知和行动非常重要。令人惊讶的是，对于大脑在哪里以及如何利用前庭对重力的估计，将最初以眼睛为中心（视网膜）坐标编码的视觉信号转换为我们感知到的以重力为中心的表征，我们知之甚少。提出的实验旨在消除这种知识差距。两项研究表明了两个可能的位点。第一个区域是尾侧顶叶内区（CIP），它负责编码物体方向的高级视觉表征。第二个是视觉后视区（VPS），已知它对前庭和视觉刺激都有反应，临床报告表明它可能与创造以重力为中心的视觉表征有关。我假设转变是渐进发生的，从V3A （CIP的主要视觉输入）的自我中心表征开始，最终以主要的重力中心表征告终：V3A（自我中心）- CIP - VPS（主要以重力为中心）。因此，我们期望V3A在严格以自我为中心（头部和/或眼睛）坐标中表示对象方向，并且实现转换的计算发生在CIP和/或VPS级别。在Aim 1中，单个神经元的视觉方向选择性将被记录在多个空间方向上（左/右耳向下滚动）。这个实验将以自我为中心（眼睛/头部）的表征与以重力为中心的表征分离开来，从而允许确定单个神经元编码物体方向的参考框架。即使在CIP和/或VPS的单个细胞水平上，向以重力为中心的表示的转换是不完整的，假设这些区域的人口活动可以表示相对于重力的物体方向。这将使用神经网络建模和概率人口代码框架进行测试，以开发如何实现以重力为中心的对象定向表示的神经理论。在Aim 2中，前庭系统在实现这种转变中的作用将通过执行双侧迷路切除术和重复Aim 1中的实验直接测试。由于前庭传入神经的电刺激可以改变感知到的视觉物体方向，因此前庭信号的消除即使不能完全消除，也有望深刻地消除重力对视觉反应的影响。任何残留的影响将归因于本体感觉信号（不是视觉，因为没有重力的视觉线索）。损伤后，重力对视觉反应的影响可能随着时间的推移而增加，这表明存在一个本体感觉信号作用增强的再学习期。本研究对于理解前庭视觉相互作用，为基础研究和临床研究开辟新的方向具有重要意义。