On December 5, Henry Gustav Molaison died in a Windsor Locks, Connecticut nursing home at age 82. At the age of 27, Mr. Molaison had experimental surgery for epilepsy. After the surgery, Mr. Molaison was never again able to lay down long-term memories.
He knew his name. That much he could remember.
He knew that his father’s family came from Thibodaux, La., and his mother was from Ireland, and he knew about the 1929 stock market crash and World War II and life in the 1940s.
But he could remember almost nothing after that.
Mr. Molaison was internationally famous as one of the most intensively studied psychological subjects ever–known by the initials H.M. Through research with H.M., knowledge of human memory has been revolutionized. What was a terrible tragedy in the life of this man made it possible for psychologists to gain invaluable insights into the role of the brain in memory, learning, and personality. He was the subject hundreds of studies by numerous researchers over the course of five decades.
Every psychology undergraduate hears about H.M.–most likely in the first psychology course they take. I’ll never forget the sense of wonder I felt when I first learned about him and how much has been learned from him. In the history of psychology his is one of the most important cases–even more so than Phineas Gage, whose terrible accident revealed the role of the frontal lobes in personality.
Molaison was born in Hartford in 1926, moved to East Hartford as a teenager and graduated from East Hartford High School. His father, Gustave, worked as an electrician at Baldwin Stewart Electrical Co.
An only child, he suffered from seizures. The cause of the seizures was never clear; he was hit by a bicyclist when he was 9, but such accidents would not typically have such devastating results….
Molaison was smart, but his seizures and the medications he took for them held him back. He had a job fixing motors, but had to give it up because the seizures made it difficult for him to work, Corkin said.
By the time he was 27, he was having up to 10 minor seizures a day and at least one major seizure a week.
That was when he underwent the experimental surgery, intended to relieve epilepsy. Hartford Hospital surgeon William Beecher Scoville, an internationally known expert in lobotomies, planned to remove a larger area of brain tissue than had been taken from patients in similar surgeries. He removed most of Molaison’s medial temporal lobe, including all or parts of the hippocampus and amygdala.
After the surgery, Molaison had profound amnesia–he had severe anterograde and partial retrograde amnesia. He could not lay down new long-term memories (anterograde) and he had lost some memories from his life before the surgery (retrograde). He still retained his procedural memories–the body memories that enable you to remember physical skills like riding a bike, swimming, or shifting gears on a manual transmission. In addition, he could gradually learn new physical tasks and form new procedural memories, even though he had no verbal memories to tell him he had done a particular task before. But for the rest of his life, each daily event, each person he encountered, he experienced as if for the very first time. In his short-term memory he could only retain any new information for a about 20 seconds. If you have seen the movie Memento, you have some sense of what it may have been like for H.M.
It was through studies of H.M. that psychologists learned about the different memory systems. Because of H.M., we now know that memory functions are dependent on the hippocampus and that the amygdala adds emotional content to our memories. Together these two parts of the brain are vital for the laying down of long-term memories along with the emotions that give them meaning.
For years, Dr. Brenda Milner of McGill University in Canada worked with H.M.
“He was a very gracious man, very patient, always willing to try these tasks I would give him,” Dr. Milner, a professor of cognitive neuroscience at the Montreal Neurological Institute and McGill University, said in a recent interview. “And yet every time I walked in the room, it was like we’d never met.”
At the time, many scientists believed that memory was widely distributed throughout the brain and not dependent on any one neural organ or region. Brain lesions, either from surgery or accidents, altered people’s memory in ways that were not easily predictable. Even as Dr. Milner published her results, many researchers attributed H. M.’s deficits to other factors, like general trauma from his seizures or some unrecognized damage.
“It was hard for people to believe that it was all due” to the excisions from the surgery, Dr. Milner said.
“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.”
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.
He also somehow sensed from all the scientists, students and researchers parading through his life that he was contributing to a larger endeavor, though he was uncertain about the details, said Dr. Corkin, who met Mr. Molaison while studying in Dr. Milner’s laboratory and who continued to work with him until his death.
Suzanne Corkin of the Massachusetts Institute of Technology began working with H.M. in 1962. She reports that he had “gist memories” from his early life. For example he could recall hiking on the Mohawk trail and a trip he took with his parents, but couldn’t recall much detail or exactly when these events happened.
Corkin equated Molaison’s death with losing a member of her family. He never remembered who she was, but he always greeted her like a friend. He told her he thought he knew her from high school.
Corkin described Molaison as an easygoing, soft-spoken, polite man with a good sense of humor. He did not typically begin conversations, but if someone prompted him, he would talk and talk, sometimes telling the same story three times in 15 minutes.
Much of what he talked about, Corkin said, reflected his desire to do whatever he could to help people.
H.M. came to understand that he was contributing to an important project, but he never truly understood the magnitude of his contribution to science.
Many times, Corkin said, she would tell Molaison how important he was. “I’d say, ‘You know, you’re really famous, you’re more famous than all the doctors who study you.’ He’d sort of smile,” she said. “He knew. For an instant.”
Thank you H.M. Rest in peace.