Optimality and adaptation in motion estimation by the blowfly visual system

This study reports experimental results on the visual system of the blowfly Calliphora vicina, in which we record analog signals from photoreceptors and action potentials from wide-field movement-sensitive cells. The photoreceptor data allow us to quantify how much information is present at the input to the visual brain. A mathematical analysis of the problem of movement detection with noisy inputs shows that it is very beneficial to adapt the computation to the statistics of the incoming signals. The experimental results suggest that the fly indeed adapts it computational strategy to a variety of statistical parameters of the input in ways predicted by the theory. Some examples of optimal processing and adaptation are presented.