You Can Choose Your Memories

In the earliest days of research, memory was thought to be populated with socalled engrams, memory traces that were localized in specific parts of the brain. To locate one such engram—for the memory of a maze—psychologist Karl Lashley taught rats to run through a labyrinth. He then cut out various parts of their brain tissue and put them right back into the maze. Though the rats’ motor function declined and some had to hobble or crawl their way woozily through the twists and turns, the ...