Henry Molaison's graduation picture Wikimedia Commons A disastrous brain operation left Henry Molaison forever stuck in the same moment. But his amnesia proved a gift to science.

I first met Henry Molaison more than half a century ago, during the spring of my third year in graduate school. I have tried to resurrect the details of my interactions with him that week, but human memory does not allow such excursions.

The explicit minutiae of unique episodes fade as time passes, making it impossible for us to vividly re-experience the details of events in the distant past. What I do know is that I was very excited to have the opportunity to study such a rare case as Henry, and I had spent months preparing.

Looking back at the results of all the tests he did that week, it was clear even then that the consequences of the operation carried out on him in 1957 – an experimental procedure to cure his epilepsy – had been catastrophic. Henry was left in a permanent state of amnesia, unable to retain any new information.

At the time of Henry’s operation, little was known about how memory processes worked. The extensive damage to the inner part of the temporal lobes on both sides of Henry’s brain made him a vital case study for memory researchers then and now.

As the years passed, his fame grew and eventually spread to countries outside North America – and all that time Henry was stuck in the same moment. From time to time, I would tell him how important and well known he was, and he would smile sheepishly, as the praise was already slipping out of his consciousness.

In his lifetime he was known as HM; only after his death, in 2008, was his identity revealed to the world.

I moved to the Massachusetts Institute of Technology in 1964. There, we were fortunate to have a Clinical Research Center on campus where my colleagues and I could admit patients for days and weeks at a time to conduct research.

Henry visited us there on 50 occasions, and I got to know him better and better as the years went by. In addition to collecting groundbreaking data in our experiments, we also documented details of his medical condition and daily life.

His nursing home chart was replete with examples of persistently failed memory. Even after living there for years, he needed directions to his room, bathroom, and lounge areas.

Not only was he confused about finding his room but, once there, he was uncertain about which of the two beds was his and which side of the double closet housed his clothes. But occasionally, his memory was surprisingly intact.

In the Eighties, when he was still allowed to smoke, the staff noted, “Henry, at times, seems to exhibit a selective memory. He has absolutely no trouble remembering when and how many cigarettes he’s had and can at times recall staff names.”

During the same period, he was troubled by false memories. On several occasions during a period of three weeks, he insisted that another resident had a pillow that had been his father’s, stating, “It has great value to me.”

Then, one day, many years after his mother died, “Henry came out of the lounge and stated, ‘my mother is coming to visit me, and there are no chairs for her to sit in!’ When the nurse tried to convince Henry his mother wasn’t coming, he became very insistent, throwing himself backwards and almost falling.”

The note in his chart concluded, “It seems you have to agree with him, or he becomes quite upset.” For most of the day, Henry saved a chair “for mother”.

He never really knew who I was but, beginning in the Eighties, he would say that he knew me from high school. We had both grown up in the Hartford, Connecticut, area but he was 11 years older than I, and we attended high schools in different cities.

So, what gave him the idea that we were schoolmates? Over the years, he heard my name over and over, and saw my face on many occasions.

As a result of this constant exposure, he built up a sense of familiarity, a sense that he knew me, and this feeling likely became stronger over time.

I was not the only person he claimed he knew from high school. At his nursing home, there was at least one nurse whom he said he had encountered during those years. One of my fondest memories of him is that he created a special name for me: “Doctress”.

Henry was a gentle person, and also intelligent, friendly, and altruistic. In 1992, when I asked him how he felt about being a research participant, he said, “I don’t mind. What is found out about me helps you to help others.”

And that “I figure that’s more important in a way, and it helps restore my memory, too. And that’s the important part right there, I say to myself. Because I know that if I could get my memory back in a way, that others can do the same; and possibly they learn too.”

In talking with a student who was conducting a research project in my lab, Henry said, “It’s a funny thing, you just live and learn. I’m living, and you’re learning.”

I was able to track down a few of Henry’s high-school classmates, and they all described him as a quiet person who kept to himself, and they noted that he was very polite. He smiled a lot and enjoyed interacting socially, but he lacked initiative. He waited for people to speak to him, but when they did he was very conversational.

Among the memories of Henry that my colleagues and I cherish are his “Henryisms”. These were the trademark phrases that dominated his conversation, such as “I’m having an argument with myself,” “There I have a question with myself,” “Question mark,” and “Knock on wood”.

Why was he always having an argument with himself? His unrelenting amnesia kept him riding on the horns of a dilemma, which must have been unsettling. He could never be sure if he had acted improperly or like a gentleman, whether he had met a particular individual before, how old he was, what month and year we were in, and whether his memory for current events was accurate.

Henry knew that he was different, and unlike many of us who keep our cards close to our chest, he told us what was on his mind. His dream, his ambition, was to be a brain surgeon, yet he believed this career path was closed to him.

He cast himself as disqualified not because his academic credentials were insufficient but because he wore glasses. Even though he was an intelligent man, he did not consider the possibility that some neurosurgeons do wear glasses or that doctors often use a microscope to view the operating field. In this case, reason was trumped by Henry’s overriding concern that he would harm the patient.

Although he was a quiet person, his inner thoughts imagined various catastrophes. When he retreated into his imagination, he witnessed the tragic scenarios that might have occurred. This line of thought was not altogether fantasy because Henry’s neurosurgeon had deemed his operation experimental, and the experiment had failed.

Henry had amazing insight into his tragedy. He knew he had epilepsy and was constantly aware that he forgot things. He also knew that his operation had been tried on only a few people before him, and he had a sense that the outcome was not good.

In 1985, Henry shared these thoughts with a postdoctoral fellow in my lab, Jenni Ogden, a neuropsychologist from New Zealand:

Ogden: Do you remember when you had your operation?

Henry: No, I don’t.

Ogden: What do you think happened there?

Henry: Well I think it was, well, I’m having an argument with myself right away. I’m the third or fourth person who had it, and I think that they, well, possibly didn’t make the right movement at the right time, themselves then. But they learnt something.

We get a sense here that Henry had come to terms with his catastrophe. It is a challenge to fathom what it must have been like to live as Henry did, with his memory decimated.

We can imagine at least two scenarios. In the first, we would wake up every morning without a memory, and it would be like dropping into hell. We would be suspicious of any new person we encountered because we did not know whether the person was a friend or a foe, and we would be hesitant and guarded when confronting new people and places.

We would constantly be stressed, agitated, and mistrustful for fear that something bad would happen.

In a different scenario, we would greet every new person with a handshake and a smile, with a glass-half-full approach to the world. We would judge new people as friends, not foes, and we would be happy to engage in conversation with anyone who spoke to us.

Henry was the latter type, which made his life much more enjoyable than if he had viewed everyone as a potential enemy.

Henry’s operation took a toll on behaviours apart from memory. His sense of smell was almost completely eliminated by the removal of areas in his cortex that process the odours that enter our body through our nose.

All he was left with was the ability to say that one test sample contained an odour and another did not. He could not identify specific odours or tell whether two odour samples were the same or different.

When attempting to name odours, his responses were unusual. On one occasion, he called cloves “fresh woodwork”, and on another he said, “dead fish washed ashore”. We know that the smell of food and drink contributes to our appreciation of them, but fortunately Henry’s loss of smell did not inhibit his desire to eat and enjoy his meals.

Whenever I asked him whether he was hungry, he typically said, “I can always eat.”

In addition to removing the memory circuits in the temporal lobe, the surgeon took out his left and right amygdala, a complex structure that sits just in front of the hippocampus.

The amygdala is one of the main sites in the brain for processing emotions, especially fear, so we wondered whether Henry was ever fearful. His caregivers could not remember his being afraid of anything.

The one exception occurred in 1986, after he underwent hip-replacement surgery. His doctor told me that Henry was afraid of being alone, but that was temporary; he eventually returned to normal after the effects of the anaesthesia had worn off.

The damage to Henry’s amygdala did affect other behaviours, and in particular, he seemed to be out of touch with his internal states.

Even though he enjoyed his meals, he never commented on being hungry or thirsty, and he did not complain of pain unless it was extreme. On one occasion, when a psychiatrist asked Henry in various ways about his sexual desire, he indicated that he did not have any, and believed that he did not masturbate.

In other words, the operation rendered him asexual.

Although not interested in sex, Henry was sustained by a different kind of motivation. Throughout the time I knew him, he clung to the belief that his research participation would benefit other people, and it did.

His case alerted neurosurgeons that they must never remove the hippocampus and surrounding structures on both sides of a patient’s brain because if they did, the person would immediately become amnesic.

An offshoot of this knowledge was that neurosurgeons who wanted to remove key memory structures on one side of a patient’s brain (say the left) had to be sure that the corresponding structures on the other side (the right) were intact. If the right side were damaged, then removing the memory area on the left side would cause a bilateral lesion and guaranteed amnesia.

To protect against the possibility that Henry’s tragedy would be repeated, doctors devised a test that could be given before an operation to see whether the alleged “good side” was in fact undamaged.

The procedure was to inject each side, on separate days, with a drug that would temporarily inactivate one side of the brain. If patients showed impaired memory when the drug was given to the abnormal side, then the conclusion would be that the alleged healthy side was not functioning properly, and the operation would not be performed.

As crucial as this lesson was for science and medicine, Henry’s life had a more universal impact. He showed the world that you could be saddled with a tremendous handicap and still carry on with your life and make a significant contribution.

He did not complain or ask for pity, and he was always a willing and cooperative research participant. Henry engaged his strong intellect to cope as best he could, and his resilience continues to be inspirational to humanity.

He stood tall in the face of his limitations, and never gave in to his tragedy.

‘ Permanent Present Tense ’ by Prof Suzanne Corkin (Allen Lane, RRP £20) is available from Telegraph Books at £18 plus £1.35 p&p. Call 0844 871 1514 or visit books.telegraph.co.uk

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