Visual perception during movements of the eyes and head

这项正在进行的研究计划的目标是对凝视转移和视觉感知之间的相互作用有一个严格的理解。在过去的100年里进行的行为实验已经注意到，在被称为眼跳的快速眼球运动期间，视觉知觉发生了广泛的变化。这些包括刺激位置、时机甚至形状的虚幻变化。对于眼球运动较慢的人来说，也发现了一系列类似的知觉效应，称为平滑追逐。总而言之，这些效应揭示了动眼信号对视觉感知的明显影响。然而，它们通常是在相当人工的条件下进行研究的，在这种条件下，受试者被指示进行单眼运动，同时呈现单独的视觉刺激。 我们假设，这些知觉错觉是神经机制的副作用，神经机制在更自然的条件下实际上改善了视觉功能。这项提议的主要目标是对这一想法进行定量的详细审查。 我们理解视觉和眼动相互作用的模型是猕猴的视皮层。特别是，我们研究了V4区、IT区、MT区和MST区的神经元，这些神经元参与了视觉信息与眼跳和平稳追踪相关的眼动信号的整合。我的实验室和其他人之前的研究表明，在眼球运动前后，这些区域的视觉处理发生了深刻的变化。然而，很少有人尝试将这些神经变化与人类受试者的知觉变化正式联系起来。此外，这些变化的功能益处尚不清楚：特定的动眼神经模式对视觉处理的影响如何提高我们定位和识别对象的能力？几乎没有人试图回答这个问题，一些人认为，动眼神经的输入根本不会改善视力。 这项拟议的研究将通过开发一种新的框架来解释眼动过程中的视觉处理来解决这一问题。这将基于眼球运动和稳定注视期间的多电极记录。这些数据将被用来从数学上描述视觉皮层神经元群体中刺激信息的编码。重要的是，这一框架导致了对动眼运动影响在自然视觉中的作用的具体预测：在空间中定位物体，识别它们，并估计它们的速度。我们将通过在动物自由观看自然场景时记录相同的神经元来测试这些预测。然后，这个框架将被扩展到眼头联合运动的研究，以确定视觉-眼动整合的计算优势是否也转化为眼头凝视的移动。总而言之，这些结果将为我们深入了解灵长类动物大脑中视觉和动眼信号之间的功能相互作用。

The goal of this ongoing research program is to develop a rigorous understanding of the interaction between gaze shifts and visual perception. Behavioral experiments conducted over the last 100 years have noted a wide range of changes in visual perception around the time of fast eye movements called saccades. These include illusory changes in stimulus position, timing, and even shape. A similar range of perceptual effects has been found for slower eye movements known as smooth pursuit. Together these effects reveal a clear influence of oculomotor signals on visual perception. Yet they have typically been studied under rather artificial conditions, in which subjects are instructed to make a single eye movement, while an isolated visual stimulus is presented. We hypothesize that these perceptual illusions are a side effect of neural mechanisms that actually improve visual function under more natural conditions. The main goal of this proposal is to examine this idea in quantitative detail. Our model for understanding the interaction of vision and eye movements is the visual cortex of the macaque monkey. In particular, we study neurons in areas V4, IT, MT, and MST, which have are involved in integrating visual information with oculomotor signals related to saccades and smooth pursuit. Previous work from my lab and others has demonstrated profound changes in visual processing in these areas around the time of eye movements. However, there has been little attempt to formally link these neural changes to the perceptual changes that are seen in human subjects. Moreover, the functional benefit of these changes is unknown: How does the specific pattern of oculomotor influences on visual processing improve our ability to localize and recognize objects? There has been little attempt to answer this question, and some have argued that vision is not improved by oculomotor inputs at all. The proposed research will address this issue by developing a novel framework for interpreting visual processing during eye movements. This will be based on multi-electrode recordings during eye movements and during steady fixation. Together these data will be used to characterize mathematically the coding of stimulus information in neuronal populations in the visual cortex. Importantly, this framework leads to specific predictions about the role of oculomotor influences in natural vision: for localizing objects in space, for identifying them, and for estimating their velocity. We will test these predictions by recording from the same neurons while the animals freely view natural scenes. This framework will then be extended to the study of combined eye-head movements, to determine whether the computational advantages of visual-oculomotor integration translate to eye-head gaze shifts as well. Together these results will provide insight into the functional interaction between visual and oculomotor signals in the primate brain.