Sensory Integration for Heading Perception

描述（由申请人提供）：这项拟议的研究旨在了解我们通过空间感知自我运动的神经回路，以及我们通过神经回路判断相对于自己的物体的运动。视觉系统处理视网膜图像运动的大规模模式（光流）来估计自我运动的方向（或方向）。然而，光流受到我们自己的眼睛和头部运动以及世界上物体运动的污染。因此，视觉系统可能无法自行解决这些问题。我们试图了解猕猴的纹外皮层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，眼球运动的参考拷贝）结合起来，以解决复杂的交织问题，即估计自我运动和物体运动。我们通过对训练过的动物进行电生理和计算研究的结合来解决这个问题。在Aim 1中，我们提出了一个通用的计算框架（多感觉归一化），该框架考虑了单个神经元对多个感觉输入的整合的不同观察结果。我们设计并测试了该模型的关键预测，以确定多感觉归一化是否发生在MSTd区域，该区域涉及自我运动感知的视觉-前庭整合。在目标2中，我们研究了眼睛和头部旋转如何改变由光流和前庭输入定义的MSTd神经元的头部调谐。我们使用群体解码方法来量化视网膜外信号和视觉深度信息对稳定眼/头旋转过程中神经元航向调整的相对贡献。在目标3中，我们研究了物体运动和自我运动之间的相互作用，并探讨了前庭输入在MST区域的两个细分中对分离自我运动和物体运动的贡献。从广义上讲，本研究解决了如何从受混淆的内部和外部变量影响的神经活动中提取感兴趣的关键变量（例如标题）的一般问题，因此在系统神经科学的许多问题中具有广泛的应用。这项拟议的研究直接关系到国家眼科研究所斜视、弱视和视觉处理项目的研究重点

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.