Kinesthetic influences on visual motion perception in normal and older adults

描述（由申请人提供）：大脑如何将关于自发运动的动觉信息与由这些运动引起的其他感觉信号整合在一起，这在很大程度上是未知的。虽然关于大脑如何整合由世界上的物体和事件产生的多种感觉信号的研究越来越多，但关于大脑如何整合动觉和视觉运动信号的研究却少得多。至于动觉和视觉之间的相互作用是如何随着年龄的增长而变化的，我们就更不清楚了。目前的建议解决了我们理解中的这些差距，特别是旨在阐明手部运动产生的动觉信号如何影响视觉运动处理以及这些相互作用如何随年龄变化-这是一个具有临床意义的问题，因为已知的视觉运动处理中与年龄相关的缺陷。第一个目标集中在多感觉整合的一个方面，这个方面经常被忽视--大脑如何决定是否耦合来自不同模态的信号，或者耦合的强度有多强（当前的研究大多集中在大脑如何在完美耦合时对不同信号进行加权）。我们将测量受试者如何适应他们的模态间耦合信号可靠性的变化，并将受试者的表现与最优贝叶斯模型进行比较，该模型通过估计个体受试者的感觉不确定性进行参数化。该模型提供了一个工具，用于测试的假设，老化导致多模态整合机制本身的变化，使我们能够折扣的影响，在单峰信号的不确定性对老年受试者的行为。第二个目标是研究大脑是否以及如何使用动觉信号来支持和增强早期视觉处理，以及这种信号如何随年龄变化。在一组实验中，我们将测试的假设，即预测信号与动觉增强一致的视觉运动信号的可检测性和测量的调整，这种增强信号之间的冲突。另一组实验将检验交互作用假说的一个强有力的版本--动觉仅足以产生视觉运动感知。在这里，我们将扩展在我们的初步研究中发现的一个现象-许多受试者报告说，看到嵌入在一个白色噪声领域的视觉运动与他们的移动的手光学搭配。为了量化生成的运动感知的强度，我们将通过实验确定感知上与报告的幻影运动匹配的真实的视觉运动。我们将进一步探讨这种动觉增强视觉处理，以确定动觉和视觉运动处理之间的潜在相互作用是乘法还是加法。最后一组实验将检验大脑使用 动觉信号，以帮助运动分割，通过增强运动信号从一个移动的目标时，手移动的目标，并通过抑制背景时，手移动它。我们将测量与年龄相关的变化，为每一个这三种形式的相互作用之间的动觉和视觉;匹配年轻和老年受试者的信号不确定性，以隔离由多感觉整合机制中与年龄相关的变化引起的变化。

DESCRIPTION (provided by applicant): How the brain integrates kinesthetic information about self-generated movements with other sensory signals caused by those movements is largely unknown. While there is a substantial and growing body of research on how the brain integrates multiple sensory signals generated by objects and events in the world, much less is known about how the brain integrates kinesthetic and visual motion signals. Even less is known about how the interactions between kinesthesis and vision change with age. The current proposal addresses these gaps in our understanding, specifically aiming to elucidate how kinesthetic signals generated by one's hand motion influence visual motion processing and how those interactions change with age - a question of clinical significance because of the known age-related deficits in visual motion processing. The first aim focuses on an aspect of multisensory integration that is often overlooked - how the brain determines whether or not, or how strongly, to couple signals from different modalities (most current research focuses on how the brain weights different signals when they are perfectly coupled). We will measure how subjects adapt their inter-modal coupling to changes in signal reliability and compare subjects' performance to that of optimal Bayesian models that are parameterized by estimates of individual subjects' sensory uncertainty. The models provide a tool for testing the hypothesis that aging leads to changes in multimodal integration mechanisms themselves, by allowing us to discount the effects of changes in unimodal signal uncertainty on older subjects' behavior. The second aim will study whether and how the brain uses kinesthetic signals to support and enhance early visual processing and how this changes with age. In one set of experiments, we will test the hypothesis that predictive signals associated with kinesthesis enhance the detectability of congruent visual motion signals and measure the tuning of this enhancement to conflicts between the signals. Another set of experiments will test a strong version of the interaction hypothesis - that kinesthesis can be solely sufficient to generate visual motion percepts. Here, we will expand on a phenomenon discovered in our preliminary studies - that many subjects report seeing visual motion embedded in a white noise field optically collocated with their moving hand. To quantify the strength of generated motion percepts, we will experimentally determine the real visual motions that perceptually match reported phantom motions. We will further explore this kinesthetic enhancement of visual processing to determine whether the underlying interactions between kinesthesis and visual motion processing are multiplicative or additive. A final set of experiments will test the hypothesis that the brain uses kinesthetic signals to aid in motion segmentation by both enhancing the motion signal from a moving target when the hand moves the target and by suppressing the background when the hand moves it. We will measure age-related changes for each of these three forms of interaction between kinesthesis and vision; matching signal uncertainty for young and older subjects to isolate changes that are result from age-related changes in multisensory integration mechanisms.