Neural correlates of active vision

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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.