Grant: Operating Grant

Slow neural processing is an inherent property that the brain must overcome in order to perceive the world in real time. For example, in the visual system, images are transduced by light detecting cells in the eye extremely slowly and the brain receives signals only ~50 ms after the image first falls on the screen (retina) of the eye. Why is this problematic? Consider what happens in tennis, when Nadal serves a tennis ball at 185 km/hour, which takes roughly 50 ms to cross the court. If Federer took 50 ms to see the ball, there is no way that he could face his opponent's serve. But we know Federer does very well to return serve, meaning that his brain can somehow compensate for delays. We believe, it is not the actual image of the ball that Federer sees, but an extrapolated image provided by his brain. How the brain can achieve this remarkable feat is not known, but is of obvious importance, not only in tennis, but in visualizing fast moving objects in our daily lives. In studying the responses of specialized cells in the retina (known as ganglion cells), we discovered that they have a remarkable ability to anticipate motion and compensate for processing delays. This is the first time in the visual system that a cell has been found to have properties to anticipate moving objects. We demonstrate that these cells can anticipate because they are endowed with specialized connections called gap junctions, which allows them to communicate lateral signals with their neighbours and figure out that an object is approaching before it actually reaches them. These ganglion cells are also known to be important in directing our eyes, allowing us to track moving objects. In fact in certain diseases, these cells malfunction and their eyes undergo involuntary oscillatory movements (Congenital Idiopathic Nystagmus). In order to find a cure for these diseases it is very important to first understand the mechanisms that govern responses of these particular ganglion cells.