Skip to main content

Construction of perceptual space-time

Final Report Summary - COPEST (Construction of perceptual space-time)

Our subjective experience of our sensory world is that there are objects, events and actions in the present moment of time in a unified and continuous space that surrounds our body. Yet, the way in which our minds construct this experience of space and time remains one of the main mysteries of the study of human cognition. Our perceptions of time or space are often inaccurate. We also know that our brain encodes sensory stimuli in a variety of different temporal and spatial scales. In other words, there are multiple mental “maps” and “clocks”—and yet no single one of these seem to correspond to our subjective experience of the world. Moreover, many studies suggest that the brain does not treat space and time as independent, but that they interact in the way we perceive and interact with the world.
The over-arching aim of this project is to define the brain mechanisms underlying spatiotemporal perception of objects, events and scenes. In particular we have focused on how the brain uses different temporal windows and spatial coordinate systems, and how these interact to give a coherent, continuous and seamless perception of our environment. In the first work package, we have developed paradigms to measure how information is combined over time and across different spatial reference frames. The results from these studies provide support for the existence of multiple “temporal integration windows” which are each linked to specific neural processes. In particular, we have found evidence that these integration windows are linked to brain rhythms.
In the second work package, we have developed methods to investigate the changes in brain state that happen in real time in order to construct our coherent percept of objects and events. We found that the power, frequency and phase of brain rhythms, as well as the connections between brain areas, can change according to task demands. In the third workpackage, we developed computational models of these spatial maps and temporal clocks. We were able to link these models to brain activity using fMRI and EEG data. In the final work package, we have explored the effects of high-level and cognitive factors, such as attention and expectation, on temporal and multisensory integration. We have found that allocating attention influences how information is processed spatially and integrated at different time scales, as well as showing a link between these processes and the brain’s predictions about what will happen.
We found that some people seem to have shorter or longer temporal windows: effectively some people see “faster” than others, with a quicker “frame rate” of perception. In addition to individual differences, we also found that people are able to strategically speed up or slow down their brain rhythms and, consequently, speed up or slow down their visual temporal resolution.