Some microscopes today are so powerful that they can create a picture of the gap between brain cells, which is thousands of times smaller than the width of a human hair. They can even reveal the tiny sacs carrying even tinier nuggets of information to cross over that gap to form memories. And in colorful snapshots made possible by a giant magnet, we can see the activity of 100 billion brain cells talking.

Hunched Over a Microscope, He Sketched the Secrets of How the Brain Works