In 1953, 27-year-old Henry Gustave Molaison underwent an experimental brain surgery in an attempt to alleviate his severe epileptic seizures. The surgery left him with a form of amnesia; he could remember many things from the past, but was unable to form new memories.
"He could tell us about where he was born, [that] his father's family was from Thibodaux, La., his mother came from Ireland," says neuroscientist Suzanne Corkin. "He talked about the towns in Hartford where he lived and about his specific neighbors. He knew the schools he attended, some of his classmates' names."
Corkin worked with and studied Molaison for almost 50 years, from 1962 until his death in 2008. She writes about how his case has helped scientists understand how memories are processed and stored in her new book Permanent Present Tense.
Her work with Molaison over those decades has taught us much of what we know about long-term memory. Corkin stresses that although his memory was almost nonexistent, Molaison was an intelligent man. This insight led to conclusions that intelligence and memory are not linked, that memory is compartmentalized, and that the ability to form new memories is localized to a specific part of the brain called the hippocampus and the surrounding cortex.
While Molaison is considered one of the most important case studies in the history of brain science, Corkin says that a sense of his celebrity was understandably lost on him.
"Every now and then I would tell him he was very famous and a lot of people knew about him in the world of scientists," Corkin says, " ... he would get this little sheepish grin and say, 'Oh, you know, isn't that nice.' You could see that it was heartwarming for him. But ... of course, as soon as he was distracted, he forgot."
On the signs of Molaison's intelligence
"We gave him IQ tests. In fact, he had an IQ test the day before his operation. A psychologist at the Hartford hospital had tested him. After his operation his IQ actually went up, which isn't a surprise because he wasn't having as many seizures. So we monitored his IQ over the years. We wanted to know that he maintained a particular level of intellectual ability. Aside from that, just talking to him in every day life, you knew you were talking to an intelligent person. Evidence of this is that he would spontaneously come up with very funny jokes. He had a wonderful sense of humor, and he would come up with little quips that were appropriate to a specific moment, nothing that he had made up before, rehearsed or he knew from his preoperative life.
"One day a postdoctoral fellow in my lab was testing Henry at the MIT clinical research center, they walked out of the testing room and the door slammed, and [one fellow] said, 'Oh, I think I've left my keys inside.' And Henry said, 'Well at least you'll know where to find them.' One of his favorite past times was doing crossword puzzles. He always had one at arm's reach and a pencil, and so I said, 'Henry, you are the puzzle king of the world,' and he said, 'I'm puzzling.' "
On short-term versus long-term memory
"Short-term memory is misunderstood and mislabeled by most of us. It's really just [what] you can remember for 30 seconds without distraction. It's the right now. It's the immediate present. It's what's on your radar screen now, not what was on five minutes ago or five minutes from now. So Henry's immediate memory was preserved. So if I said to him, 'Henry, I have this favorite plant, white petunias, that I like very much.' And then I'd ask him to say back [to me] what I had just said ... and he was able to do that. ... [But] if I said to him five minutes later, 'What is my favorite plant?' he would have no idea. So anything beyond 30 seconds falls into the domain of long-term memory."
On Molaison's later years
"He had to go to the bathroom a lot, so the nurses would take him and he would do what he had to do, and then 10 minutes later he would ask to go again, and they would say, 'Henry, you just went.' We learned from his full-body autopsy that he had colon cancer, and maybe this is why he had to go to the bathroom frequently. So yes, the later years of his life were sometimes unpleasant for him. At the same time, he had wonderful care in the nursing home. The aides really doted on him, and there were three in particular that they called 'The Island Ladies.' They were from Jamaica, and they loved Henry, and they called him their 'teddy bear,' and he had very caring people around him. His medical needs were for the most part met. So it was a mixed bag."
On Molaison's postmortem scan
"The scans were beautiful. They were much clearer than what you could see in a living person, partly because we scanned him for so long. You can't scan a living person for hours and hours. But the other thing that made them so spectacular was that there was no movement. If you or I go into an MRI scanner we're still breathing, and our heart is beating, and we might have a twitch in our right shoulder. And all of this makes you move and makes your brain move. Of course [after he died] Henry didn't have a heart rate or respiration, and we scanned him for a long time. So we could see individual structures much more clearly. We could see the spaces in his brain much more clearly. We could see they were enlarged because he had dementia. We could see the white matter was thin, the telephone lines were thin in certain places. We could see the dura, the outside covering of the brain. Much more detail from the postmortem scans."
On whether it was frustrating to work with Molaison
"The only thing that was a teeny bit annoying for researchers was if they heard the same story over and over and over again. So, you know, we used to pick him up at his nursing home and drive him up to MIT and then take him home again, and these car rides were a couple of hours. There were certain billboards along the way that [would] evoke the same story over and over again. Howard Eichenbaum had a funny experience where he had a coffee cup from McDonald's in his car and every time Henry looked at this, he talked about his friend named so-and-so McDonald, and so after a while Howard got so sick of listening to the story that he put the coffee cup under his seat. But, you know, it was just funny. It wasn't frustrating or annoying. It was amusing. And this was Henry being Henry. This is what he did. So we just accepted it."