Grant: Research Tools and Instruments

A key role of the brain is to control movement. Because most neuroscience research occurs in restricted preparations, there is a gap in our understanding of the control of complex motions required for free movement. Maneuverability is critical for survival, and susceptible to disease, injury, and ageing. What behaviour is likely to provide the greatest insight into fundamental algorithms for complex motion control? Animals moving through water or on land are greatly assisted by passive stabilizing mechanisms of buoyancy and ground reaction, respectively. My laboratory focuses on flight because it requires precise control in all degrees of freedom. Most other groups taking this approach work with fruit flies because of molecular tools available to manipulate their nervous system. However, fly brains are too small to study outside of tethered preparations. We study flight in birds, including species that are small enough to perform complex trajectories in the laboratory. Our NSERC-funded work on biomechanics allowed us to develop a custom tracking system, which revealed a universal framework for classifying and comparing maneuvers in flight. Our research funded by the Human Frontier Science Program allowed us to develop a virtual reality flight environment, which revealed novel visual guidance strategies for avoiding catastrophic collisions during movement. The results of these two research programs present an exciting new opportunity to examine visuomotor integration in the brain during flight. In preparation for this new phase of research we have developed optogenetic approaches. We can now reliably express channelrhodopsin in the visual midbrain nuclei of birds, and manipulate neural activity using light. To apply this approach in vivo we now require an integrated, closed loop virtual reality environment, meaning that active feedback from the animal tracking will drive both visual stimulus and neurophysiological manipulation. Our current technologies are too outdated and too slow to permit closed loop control, especially on a time scale relevant to animal behaviour. We will build a custom virtual reality environment that has three essential features: 1) a fully automated tracking system to allow for accurate and rapid (high-throughput) measurements of behaviour; 2) light delivery capacity to manipulate neural activity during flight; 3) augmented closed loop capacity to change the sensory environment and neural stimulus in response to animal motion and head position. Building a unique rig with these three essential features will allow for powerful tests of hypotheses that unify biomechanics and visual neuroscience. Two examples of specific research problems are: a) the role of object size and movement on the control of acceleration and deceleration; b) the role of inhibitory reciprocal connections in visual motion nuclei on the neural algorithms for collision avoidance.