Final Activity Report Summary - CIRCUIT ANALYSIS (Functional analysis of neural circuits identified by molecular markers and trans-synaptic tracers) In the project funded by this Marie Curie Fellowship, the proposed goal was to investigate the circuitry and functional connections of neurons in the retina, to gain insight into the workings of neural circuits in the retina in particular, and ultimately of the brain. Thomas Münch has discovered a novel form of processing of neural circuits, and a novel image processing function performed by the retina: he discovered how the retina can recognize approaching objects. The detection and avoidance of approaching objects, for example of charging predators, is important for any animal. It has long been known that animals show stereotyped behavioural responses to approaching visual stimuli, but until now it has not been known how the circuits in the nervous system can distinguish approaching from non-approaching stimuli. In a second project, the fundamental knowledge about the retina could be applied to a novel form of treating blindness, by applying a microbial light-sensitive protein to specific cells in the retina. As a consequence, these cells can now take over the function of the dying photoreceptors. Together with other colleagues in the laboratory of Botond Roska at the Friedrich Miescher Institute in Basel, Thomas Münch has shown in a mouse model of retinal degeneration, that this treatment brings back light responses of the retina, responses of the visual cortex, and light-guided behaviour of the treated animals. After more research and testing, this approach to treating blindness may eventually also be applicable to treating human blindness.