Today, many people with severe temporal lobe epilepsy have had their lives transformed by a brain operation where the temporal lobe and its underlying hippocampus is removed on one side of the brain. In these cases the epileptic seizures begin in the hippocampal and temporal lobe tissue on one side of the brain, and by removing that tissue, the seizures stop or are greatly reduced.
However, back in 1953, when this was a very experimental operation, neurosurgeon William Scoville decided to remove the hippocampus on both sides of 27-year-old Henry Molaison's (HM's) brain. The operation was successful in that it greatly reduced Henry's epileptic seizures, but it tragically left him with a dense, global amnesia.
Of course, before Henry's surgery it was not known that the hippocampus was essential for storing new memories. Largely as a result of thousands of studies of HM and later studies on other patients with damage to their hippocampus, neuroscientists discovered that if one hippocampus was intact and healthy, memory remained good enough for the patient to live a normal life, but if both hippocampi were removed or damaged by disease, the patient, like Henry, suffered a global amnesia.
People with a global amnesia can no longer consciously learn or remember new personal experiences or facts from the time of the brain damage, whether verbal (words) or nonverbal (sounds, patterns, faces). They are, however, still able to learn new motor patterns at an unconscious level. For example they may be able to learn to ride a bike although they will not remember that they have learned this skill!
Henry also suffered a period of memory loss for events and facts that occurred before his brain damage; a retrograde amnesia that extended for eleven years before his surgery. It was as if he lived in a time capsule that stopped when he was 16 years old. For example, he had no conscious memories of public events after the age of sixteen years. If he was asked about the content and timing of public events, he had normal recall of events from the 1940s (compared to neurologically normal Americans of his own age), but impaired recall for events (and famous people) from the 1950s until his death. His occasional recall of famous people and events that were publicized after his operation in 1953 was spasmodic at best, and he tended to confuse those memories with other events, or he confused them in time.
In the following recorded conversation I had with him in 1986, he confused Elvis Presley's death (in 1977) with the assassinations of President John Kennedy and Robert Kennedy. An Elvis Presley recording was first played on the radio in 1954, one year after Henry's operation, so to recall anything at all about Elvis was remarkable, and perhaps an indication of how important a figure Elvis was to young people in the mid-1950s.
Jenni: Do you know who Elvis Presley is?
Henry: He was a recording star, and he used to sing a lot.
Jenni: What sort of things did he sing?
Jenni: Do you like to jive, or did you like to jive?
Jenni: (laughing) Why not?
Henry: I liked to listen, that was all.
Jenni: Do you think he is still alive, Elvis Presley?
Henry: No, I don't think so.
Jenni: Have you any idea what might have happened to him?
Henry: Well I believe he got the first bullet I think that was for Kennedy, I think it was.
Jenni: You remember Kennedy?
Henry: Yes, Robert.
Jenni: What was he?
Henry: Well, he was the President. I think about three times. He was appointed to President too.
Jenni: He got a bullet. What was that all about?
Henry: Well, they were trying to assassinate him.
Jenni: And did they? Did they kill him or not?
Henry: No they didn't.
Jenni: So is he still alive?
Henry: Yes, he is still alive, but he got out of politics in a way.
Jenni: I don't blame him.
Henry: No, guess not.
Jenni: How long ago was he the President do you think?
Henry: He became the President after Roosevelt. 'Course there was Teddy Roosevelt. That was a long time before that.
Jenni: What is Franklin Roosevelt's wife's name?
Henry: I can't think of it.
Jenni: It starts with E I think--Eleanor. You were going to say that?
Henry: No, I wasn't. I was going to say Ethel. (Ethel was Robert Kennedy's wife.)
Copyright: Jenni Ogden