Grant: Discovery Grants Program - Individual

In previous NSERC-funded work, we imaged human brain activity to show how parietal cortex plans actions relative to current gaze direction, and we perturbed different brain areas using trans-cranial magnetic stimulation (TMS) to show how both parietal and frontal 'eye fields' are involved in the memory and integration of visual objects across eye movements. Here, we will test a conceptual model in which these same eye movement areas interact with early visual areas and with cognitive areas in prefrontal cortex for different aspects of visual integration. Specifically, we hypothesize that prefrontal cortex is more involved in visual integration tasks that involve conscious intention, whereas early visual areas are more involved in visual integration that occurs at a sub-conscious level. We will localize these various brain regions with the use of brain imaging at York's new Sherman fMRI centre. In my lab, we will then use TMS to briefly and safely perturb the function of these areas during the eye movement / memory intervals between seeing different visual objects. We will do this in tasks that involve conscious or unconscious integration of visual information. Finally, we will develop a formal computation model, based on our current conceptual model and the new data, to explain how the brain does this. This project will address one of the most important and timely questions in visual neuroscience; how are signals from different brain areas coordinated in real world conditions (in this case to integrate visual, motor, and memory signals for spatial representation)? Moreover, an understanding of the function and performance limits of this system is vital for the safe operation and efficient design of human-machine interfaces in tasks that involve the memory and integration of visual information across eye movements, such as driving a car at high speeds down the highway.