Imagine the brain as a giant switchboard covered with thousands of buttons, knobs, dials and levers that control aspects of our thought, emotions, behavior, and memory. (You can think of the movie Inside Out, if you like).

For more than a century, neuroscientists have been methodically flipping these switches on and off, alone or in combination, to try to understand how the machine works as a whole. But this is easier said than done. The cellular circuits that control mind and behavior tangle together throughout the opaque, gelatinous mass of our brain tissue and don't come with handy on/off switches for easy reverse engineering.