Understanding how the brain processes sensory information in real-time to generate meaningful behaviors is one of the outstanding contemporary challenges of neuroscience. Visually guided collision avoidance behaviors are nearly universal in animals endowed with spatial vision and offer a favorable opportunity to address this question. This talk will summarize the current understanding of their generation at the level of neural networks, single neurons and their ion channels. The focus will be on a model system that has proven particularly suitable for this purpose, the locust brain, but will also tie the results learned in this preparation to studies carried out in a wide range of other species.