CoPeST · Construction of perceptual space-time

The foundation of lived experience is that it occurs in a particular space and time. Objects, events and actions happen in the present moment in a unified space which surrounds our body. As noted by Immanuel Kant, space and time are a priori concepts that organize our thoughts and experiences. Yet basic laboratory experiments reveal the cracks in this illusion of a unified perceptual space-time. Our subjective experience is a construction created out of the responses of numerous sensory detectors which give only limited information. In terms of space, the sensory input from a multitude of tiny windows is organized based on the coordinates of the receptor system, such as the fingertip or a specific location on the retina. In terms of time, sensory input is summed over a limited period which varies widely across different receptor types. Critically, none of these sensory detectors has a spatial-temporal response that corresponds to our subjective experience. Nonetheless, the mind constructs an illusion of unified space and continuous time out of the variegated responses. The goal of this project is to uncover the mechanisms underlying smooth and continuous perception. This project builds on a decade of groundwork in studying specific instances of the integration of visual information over space and time with a new focus on the mechanisms that unite the various phenomena which have up to now been studied separately. A combination of behavioral, neuroimaging and computational approaches will be used to identify the mechanisms underlying spatio-temporal continuity in high-level perception. We will track the dynamic shifts between the various temporal and spatial coordinate frames used to encode information in the brain, a topic which has remained largely unexplored. This research project, driven by specific hypotheses, aims to uncover how uni-sensory, ego-centric sensory responses give rise to the rich, multisensory experience of unified space-time.