How the Binding of Two Brain Molecules Creates Memories That Last a Lifetime

The original version of this story appeared in Quanta Magazine. When Todd Sacktor was about to turn 3, his 4-year-old sister died of leukemia. A swing set with two seats instead of one," he said, recalling the lingering traces of her presence in the house. "There was this missing person--never spoken of--for which I had only one memory." That memory, faint but enduring, was set in the downstairs den of their home.