H.M., an amnesiac whose condition opened new doors in the study of memory, died on Tuesday at age 82. A 1953 brain operation left H.M., now revealed to be Henry Gustav Molaison, with no ability to form new long-term memories. From then on, every time he met someone, or experienced something, it would be just like the very first time. His short-term memory was fine. From the New York Times:
“The study of H. M. by Brenda Milner stands as one of the great milestones in the history of modern neuroscience,” said Dr. Eric Kandel, a neuroscientist at Columbia University. “It opened the way for the study of the two memory systems in the brain, explicit and implicit, and provided the basis for everything that came later – the study of human memory and its disorders.”"H.M., An Unforgettable Amnesiac, Dies at 82"
Living at his parents’ house, and later with a relative through the 1970s, Mr. Molaison helped with the shopping, mowed the lawn, raked leaves and relaxed in front of the television. He could navigate through a day attending to mundane details – fixing a lunch, making his bed – by drawing on what he could remember from his first 27 years.