Neural correlates of active vision

对大脑过程的主要见解来自于研究过程是如何被自上而下的影响所调节的。具体来说，人们对行为如何塑造感知的兴趣越来越大。脑成像加深了对参与视觉运动转换的神经网络的理解。然而，人们对这些转换的时间方面知之甚少，因为脑成像不能及时解决小细节，而且脑电图（EEG）是以较差的空间分辨率为代价的。因此，对于依赖动作的感知区域的激活是如何随时间进化的，人们知之甚少。然而，多元分析的最新进展表明，从人类头皮记录的脑电图数据可以详细了解视觉和视觉运动计算的时间过程。我的研究项目的目标是——表明大脑对行动的准备触发了感知区域的活动，感知区域携带着行动对象的信息，为了确定这些动作依赖激活的目的——确定大脑活动在空间和时间上的模式，这些模式将动作所针对的物体的多个方面的信息结合在一起——确定动作依赖的感知信息起作用的空间坐标系统，我将使用多变量脑电图分析，单独使用或与脑成像结合使用。我的项目的主题1旨在表明脑电图信号反映了物体形状的视觉信息，这些信息与随后的抓取时间一致，但不涉及不需要形状信息的运动。我将测试关于哪些对象部分嵌入在EEG信号中的信息（可能是参与者将抓住的点附近的部分）。我将测试脑电图对感觉与外观不同的物体的反应，以探测动作控制机制。此外，我将探讨抓取和工作记忆之间的干扰。主题2将探讨动作依赖增强的神经相关性，这些增强是关于物体的多个视觉方面的，这些视觉方面传达了对计划抓取重要的物体的形状、大小和重量等信息。我将使用EEG结合脑成像来整合大脑活动的详细时空信息。主题3将关注手的位置，眼睛的运动和物体的方向对视觉形状信息的动作依赖激活的影响。总而言之，本研究将采用一种全面的方法来调查一些主要的与行动相关的自上而下的视觉影响，有效地利用这些机制作为研究行动中的视觉系统的透镜。这项研究的结果有可能进一步加深我们对大脑作为一个动态系统的理解，该系统根据其目标和行动来塑造其感知过程，这对未来脑机接口的发展具有重要意义。

Major insights into the brain's processes come from studying how processes are modulated by top-down effects. Specifically, there is growing interest in how actions shape perception. Brain imaging has deepened the understanding of the neural networks engaged in visuomotor transformations. Yet there is little knowledge of the temporal aspects of these transformations, because brain imaging cannot resolve small details in time, and because electroencephalography (EEG) comes at the expense of poor spatial resolution. Thus, there is little understanding of how action-dependent activation of perception regions evolves in time. Recent advances in multivariate analysis, however, have demonstrated that EEG data recorded from the human scalp allow for detailed insights into the time course of visual and visuomotor computations. The objectives of my research project are - show that the brain's preparations for actions trigger activity in perceptual areas that carry information about the objects of actions, and to identify the purpose of these action-dependent activations - identify the patterns of brain activity in space and time that bind together information about multiple aspects of objects targeted by actions - identify the spatial coordinate systems in which action-dependent perceptual information works I will use multivariate EEG analysis, alone or in combination with brain imaging. Theme 1 of my project aims to show that EEG signals reflect visual information about object shapes that builds up aligned in time with subsequent grasp but not reach movements which require no shape information. I will test information about which object parts are embedded in the EEG signals (probably parts near the points where participants will grasp). I will test EEG responses to objects that feel different from what they look like to probe for action control mechanisms. Also, I will probe for interference between grasping and working memory. Theme 2 will investigate the neural correlates of action-dependent enhancement of multiple visual aspects about objects conveying information about shape, size, and weight of objects features important to plan grasping. I will use EEG together with brain imaging to integrate detailed temporal and spatial information about brain activity. Theme 3 will be concerned with the influences of hand positions, eye movements as well as object orientations on action-dependent activation of visual shape information. In sum, the proposed research will pursue a comprehensive approach to investigating some of the major action-related top--down influences on vision, effectively using these mechanisms as a lens to study the visual system in action. The outcome of this research has the potential to further our understanding of the brain as a dynamic system that shapes its perceptual processes, depending on its goals and actions with additional important implications for the development of future brain-computer interfaces.