How are sensory stimuli from the outside world processed in the brain? How do the sensory neuronal signals interact with the persistent brain activity? And how does behavior arise from neuronal activity? These are some of the most exciting neuroscience questions of our time. In the Optical Neuroimaging Unit, we develop novel techniques to image neuronal activity during behavior. By visualizing brain activity on a cellular level in the awake mouse we investigate how the brain processes information. Simultaneously, we observe the behavior in detail. By finding correlates between neuronal activity and behavior, we hope to address some of the mysteries of the brain.