First, the sound hits your ear, activating a series of structures from the cochlea (where vibrations are turned into electrical impulses) to the brain’s cortex. When you recognize the tune, your auditory cortex is connecting with regions that handle memory retrieval. Then, if you are starting to tap your foot, you’ve activated the motor cortex in a very particular way because you’re tapping the exact beat of the song. Finally, if the song has you feeling good, the song has turned on your brain’s reward system, ancient powerful circuitry triggered by essentials for survival like eating and sex.