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方面发挥着至关重要的作用，从根本上影响感官知觉和运动规划。因此，了解如何使用前庭信息（表示自我相对于重力的方向）来创建稳定的以重力为中心的视觉场景表示，对于理解感知和行动非常重要。令人惊讶的是，我们对大脑在何处以及如何使用前庭重力估计将首先以眼睛为中心（视网膜）坐标编码的视觉信号转换为我们感知的以重力为中心的表示形式知之甚少。所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。第一个是尾顶内区域（CIP），已知它编码物体方向的高级视觉表示。第二个是视觉后侧裂（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参与创建以重力为中心的视觉表征。我假设这种转变是逐步发生的，从 V3A（CIP 的主要视觉输入）中的自我中心表示开始，最终以主要以重力为中心的表示：V3A（以自我为中心）→CIP→VPS（主要以重力为中心）。因此，预计 V3A 表示严格以自我为中心（头部和/或眼睛）坐标中的对象方向，并且实现转换的计算发生在 CIP 和/或 VPS 级别。在目标 1 中，将用猴子在多个空间方向（左/右耳向下滚动）记录单个神经元的视觉方向选择性。该实验将自我中心（眼睛/头部）与以重力为中心的表示分离，从而允许确定单个神经元编码对象方向的参考系。即使在 CIP 和/或 VPS 中的单细胞水平上向重力中心表示的转换不完整，但假设这些区域中的群体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总体代码框架进行测试，以开发如何实现物体方向的重力中心表示的神经理论。在目标 2 中，前庭系统在实现这一转变中的作用将通过进行双侧迷路切除术并重复目标 1 中的实验来直接测试。由于前庭传入神经的电刺激可以改变感知的视觉对象方向，因此前庭信号的消除预计将深刻地（如果不是完全的话）消除重力对视觉反应的影响。任何残留效应都将归因于本体感受信号（不是视觉，因为不存在重力的视觉提示）。病变后，重力对视觉反应的影响可能会随着时间的推移而增加，这表明本体感觉信号的作用增强的重新学习期。这项研究对于理解前庭视觉相互作用以及为基础和临床研究建立新方向非常重要。