And the answer:
I would like to know how some memories persist forever. How do you remember your first love experience for the rest of your life. Neuroscientist Kausik Si, then a postdoctoral fellow in my lab, and I discovered a protein called CPEB that has the very interesting characteristic of self-perpetuation. That might be a clue to how memory is sustained over long periods. But we don't know for sure yet.
It reminds me of Eternal Sunshine of the Spotless Mind, one of my favourite films. I'm thinking now of a story about controlling memories. A character pressing his head every time he wants to remember something. The only trouble is, if he gets it wrong, he'll never be able to forget.