Sensory Integration for Heading Perception

描述(申请人提供)：拟议的研究试图了解神经回路，我们通过它感知我们在空间中的自我运动，并通过它我们判断物体相对于我们自己的运动。视觉系统处理视网膜图像运动(光流)的大规模模式，以估计自我运动(或航向)的方向。然而，光流被我们自己的眼睛和头部的运动以及世界上物体的运动所污染。因此，视觉系统本身很可能无法解决这些问题。我们试图了解猕猴纹外皮质的神经回路如何将视觉运动与前庭信号和其他非视觉输入来源(例如，眼动的传出副本)结合起来，以解决估计自我运动和物体运动的复杂相互交织的问题。我们通过在经过训练的动物身上进行电生理学和计算机研究相结合的方法来解决这一问题。在目标1中，我们提出了一个通用的计算框架(多感觉归一化)，它解释了关于单个神经元整合多个感觉输入的不同观察结果。我们设计并测试了该模型的一个关键预测，以确定MSTd区是否发生了多感觉正常化，该区域参与了视觉-前庭整合的自我运动感知。在目标2中，我们研究了眼睛和头部旋转如何改变MSTd神经元对由光流和前庭输入定义的头部的调谐。我们使用群体解码的方法来量化视网膜外信号和视觉深度信息在眼睛/头部旋转过程中对稳定神经元航向调整的相对贡献。在目标3中，我们考察了物体运动和自我运动之间的相互作用，并探索了前庭输入在MST区两个分区中对分离自我运动和物体运动的贡献。从广义上讲，这项研究解决了如何从受内外变量混淆影响的神经活动中提取感兴趣的关键变量(如航向)的一般问题，因此在系统神经科学的许多问题中都有广泛的应用。这项拟议的研究与国家眼科研究所的斜视、弱视和视觉处理计划的研究重点直接相关 公共卫生相关性：了解自我运动感知的神经基础可能会促进治疗阿尔茨海默病等神经变性患者的空间定向障碍的新策略。阿尔茨海默病被广泛认为是一种记忆障碍，但也伴随着严重的知觉缺陷，包括判断航向的能力受损。对灵长类动物模型中这些功能的深入了解将有助于针对相关大脑区域的新疗法，并有助于开发基于训练的康复计划。

DESCRIPTION (provided by applicant): The proposed research seeks to understand the neural circuits by which we perceive our self-motion through space and by which we judge the motion of objects relative to ourselves. The visual system processes large- scale patterns of retinal image motion (optic flow) to estimate the direction of self-motion (or heading). However, optic flow is contaminated by our own eye and head movements, as well as motion of objects in the world. As a result, the visual system likely cannot solve these problems on its own. We seek to understand how neural circuits in extrastriate cortex of macaques combine visual motion with vestibular signals and other sources of non-visual input (e.g., efference copy of eye movements) to solve the complex intertwined problems of estimating self-motion and object motion. We approach this through a combination of electrophysiological and computational studies in trained animals. In Aim 1, we propose a general computational framework (multisensory normalization) that accounts for diverse observations regarding integration of multiple sensory inputs by single neurons. We devise and test a critical prediction of the model to establish whether multisensory normalization takes place in area MSTd, which is involved in visual-vestibular integration for self- motion perception. In Aim 2, we examine how eye and head rotations alter the tuning of MSTd neurons for heading as defined by optic flow and vestibular inputs. We use a population decoding approach to quantify the relative contributions of extra-retinal signals and visual depth information to stabilizing the heading tuning of neurons during eye/head rotation. In Aim 3, we examine the interactions between object motion and self- motion and explore the contributions of vestibular inputs to dissociating self-motion and object motion in two subdivisions of area MST. In broad terms, this research addresses the general problem of how critical variables of interest (e.g., heading) are extracted from neural activity that is influenced by confounding internal and external variables, and thus has broad application to many problems in systems neuroscience. The proposed research is directly relevant to the research priorities of the Strabismus, Amplyopia, and Visual Processing program at the National Eye Institute PUBLIC HEALTH RELEVANCE: Understanding the neural basis of self-motion perception may promote new strategies for treating spatial disorientation in patients with neurodegeneration such as Alzheimer's disease. Alzheimer's disease is widely known as a memory disorder, but is also accompanied by severe perceptual deficits including impaired ability to judge heading. A deeper understanding of these functions in a primate model will help in targeting new therapies to relevant brain areas and in developing training-based recovery programs.