In order to survive in the world, an organism must be able to adapt to an ever-changing environment. This would not be possible without the brain and the nervous system, which control all important activities in the body: they process sensations, control the function of organs, guide and enable movements and allow us to think. Scientists at the Max Planck Institute of Neurobiology in Martinsried seek to understand how such a complex system can develop, how it functions and what happens when it is injured or attacked by germs. To this end, they focus on the minute changes of nerve cells, e.g. during learning, as well as on the structure of complex nerve networks, e.g. in the visual cortex of flies. The scientists are also investigating the causes of illnesses, such as multiple sclerosis. The long-term goal is a new or enhanced therapy.