"Four-Nine-Seven, Oh-Two-Five-Four. Got it?"

"Sure. See you later!"

As soon as I hung up the phone, I realized that I had no paper or pen. As I rifled my room for writing implements, I wondered: "How am I remembering these numbers?"

This simple process of remembering things for a short period of time happens every day of our lives; it is fundamental to our experience of the world. Memory over a short period of time, called 'working memory', has generated much interest recently both because of its importance to many higher brain functions and the evolution of powerful techniques to study brain processes, such as PET and fMRI. Based on these techniques, scientists can pursue exciting questions about the neural underpinnings of working memory.