Through the combination of in vivo optical imaging and chronic expression of genetically encoded calcium indicators it is now feasible to directly 'watch' brain activity patterns related to specific behaviors. I will introduce wide-field calcium imaging and multi-fiber photometry as two complementary methods that enable measurements across mouse neocortex and in large sets of subcortical regions, respectively. Specific patterns of brain-wide signal flow that occur in mice performing whisker-based or auditory sensory discrimination tasks will be discussed, highlighting salient patterns related to short-term memory. In addition, taking advantage of chronic measurements over weeks, I will present salient changes in brain dynamics that relate to task learning.