Research Background One of the most important functions of the central nervous system is the generation of movement in response to sensory stimulation. The eyes have a simple, yet well defined repertoire of movements and the premotor circuitry controlling eye movements is now understood at a level that is sufficient to provide a basis for designing and interpreting more complex experiments to probe higher brain functions. I am focusing my research on characterizing the control signals present in the frontal cortex, basal ganglia superior colliculus, and brainstem retircular formation to determine how they interact to produce the behaviour. Experiments consist of recording from individual neurons in the brain while the alert animal performs a variety of visuomotor tasks.
Neuronal activity is correlated to various aspects of the orienting behaviour.
In addition, the activity of neurons in these brain regions can be artificially altered using electrical microstimulation or microinjection of transmitter substances. We are also investigating how the control of visual fixation and saccadic eye movements may be disrupted in patient with various neurological or psychiatric disorders. Knowledge gained from the animal experiments complements ongoing experiments in which we record eye movements from subjects diagnosed with attention deficit hyperactivity disorder, Tourette syndrome, Parkinson's disease, as well as patients suffering from stroke or tumour growth. The patients perform several oculomotor tasks and we characterize any deficits they may have and relate them to our understanding of the neural circuitry controlling eye movements. Funding for my laboratory is provided by the Canadian Institutes for Health Research, the National Sciences and Engineering Research Council of Canada, the EJLB Foundation, the Human Frontiers Science Program, the Tourette Syndrome Association, and Queen's University.