Henry Molaison grew up in Connecticut, and as a boy he was knocked unconscious for several minutes in a bicycle accident. By his late teens he was having major seizures. He found work on an electric motor assembly line, but the seizures came too often and he had to leave. By the age of 27, he was having about 10 minor blackouts and one major seizure every week. High doses of Dilantin and Phenobarbital did not control them. So his parents and his doctor turned to a last resort, an experimental operation on his brain. It would reduce the seizures. It would also turn Henry into Patient H.M., whose case showed scientists that memories are made in particular places in the brain. What would the operation take from him?
Patient H.M.: The Man Who Couldn't Make Memories
After 1953 surgery, Henry Molaison could form no new long-term memories of events, and his brain was later cut into 2,401 slices.
Chapter 1
A Last Resort
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Frequently Asked Questions
What was wrong with Henry Molaison after his 1953 surgery?
He had profound anterograde amnesia, meaning he could no longer form new long-term memories of facts or events. He kept his childhood memories and most events until about two years before the operation. His intelligence, vocabulary and personality stayed largely the same.
What did Brenda Milner's mirror-tracing experiment show?
Henry traced a five-pointed star while seeing it only in a mirror, and his skill improved over three days of practice. Yet each time he insisted he had never seen the task before. This showed that procedural memory for skills relies on different brain structures than declarative memory for facts and events.
What happened to Henry Molaison's brain after he died?
After his death on December 2, 2008, his brain was frozen and cut into 2,401 sections, each about 0.07 millimetres thick. About 400,000 people watched the slicing online. It is now preserved as a digital 3D model that researchers can study at a microscopic level.
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