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(由申请者提供)：重力在塑造我们对世界的体验方面发挥着关键作用，在基本层面上影响着感官知觉和运动规划。因此，了解前庭信息如何可以用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是重要的。令人惊讶的是，关于大脑可能在哪里以及如何使用前庭重力估计来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所感知的以重力为中心的表示，人们知之甚少。拟议的实验旨在消除这一知识鸿沟。两条研究路线表明了两个可能的基因座。第一个是尾侧顶内区(CIP)，它编码物体定向的高级视觉表征。第二个是视觉后侧索(VPS)，已知它对前庭刺激和视觉刺激都有反应，临床报道认为它可能参与了以重力为中心的视觉表征。我假设转换是循序渐进的，从V3A(CIP的主要视觉输入)中的以自我为中心的表示开始，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的(头部和/或眼睛)坐标中的对象定向，并且实现变换的计算发生在CIP和/或VPS级别。在目标1中，将记录猴子在多个空间方向(左/右耳朵向下滚动)对单个神经元的视觉定向选择性。这项实验将以自我为中心的(眼睛/头部)与以重力为中心的表征分离，允许确定单个神经元编码物体方向的参照系。即使在CIP和/或VPS的单细胞水平上向重力中心表示的转换是不完整的，也可以假设这些区域中的种群活动可以代表相对于重力的对象定向。将使用神经网络建模和概率总体编码框架来测试这一点，以开发关于如何实现以重力为中心的对象取向表示的神经理论。在目标2中，将通过双侧迷路切除和重复目标1的实验来直接测试前庭系统在实现这种转变中的作用。由于电刺激前庭传入可以改变感知的视觉对象定向，前庭信号的消除有望深刻地消除重力对视觉反应的影响，如果不是完全的话。任何残留效应都将归因于本体感觉信号(而不是视觉，因为重力的视觉线索将不会出现)。损伤后，重力对视觉反应的影响可能会随着时间的推移而增加，这表明了一个重新学习的时期，在这个时期，本体感觉信号的作用增加了。这项研究对于理解前庭-视觉相互作用和建立基础和临床研究的新方向具有重要意义。