Psychology Case Study: Henry Gustav Molaison

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Instructor: Elisha Madison

Elisha has Master's degree in Ancient Celtic History & Mythology, as well as a Bachelor's in Marketing. She has extensive experience creating & teaching curricula in college level education, history, English, business and marketing.

Due to Henry Gustav Molaison's accident and resulting epilepsy, neuroscience was born. This lesson discusses the surgery that changed his life and brain science forever. Updated: 10/29/2021

Who Was 'Patient HM'?

Henry Gustav Molaison hit his head when he was nine, which caused epileptic fits shortly after. Henry started having over 10 epileptic fits a day, which made it almost impossible for him to have any type of life. He was born in 1926, so by the time he was in his 20s and looking for help it was still only the early 1950s.

He met Dr. William Scoville, who believed removing Henry's hippocampus from his brain, effectively lobotomizing him, would completely alleviate the seizures. Although Henry was nervous, he agreed to the surgery, which changed not only his life, but neuroscience forever.

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  • 0:04 Who Was 'Patient HM'?
  • 0:41 Anterograde Amnesia
  • 1:35 The Hippocampus
  • 2:22 Types of Memory
  • 3:09 Brain Study
  • 3:59 Lesson Summary
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Anterograde Amnesia

In 1953, Henry Molaison had his hippocampus removed. He was only 27. When he was out of surgery, doctors started to realize there was something incredibly wrong. Although Henry's epilepsy seemed to be gone, Henry could no longer make memories. He had what psychologists and doctors call severe anterograde amnesia.

Anterograde amnesia is the inability to develop and keep new memories. Old memories that have been stored as long-term memories are retained, but they are fuzzy in recollection.

Immediately after the surgery, Henry could recall all of his old memories from before the surgery without major problem. But even the simplest new memories were lost to him. He could not remember what he ate for lunch, or recall the names of doctors that he met just a few minutes before. So why was this sad case such a miracle for brain science?

The Hippocampus

Due to Henry's new condition and amnesia, he became one of the most studied men in history. Eventually called ''Patient HM,'' he was analyzed and studied for over 50 years of his life, until he died at age 82. Henry never really aged in his mind, always behaving like the 27-year-old man he was when he came out of surgery. However, when he saw himself in a mirror he wouldn't be surprised; he didn't really seem to be overly emotional about anything as he grew older.

Due to constant study of Henry, doctors were able to learn what the hippocampus actually does. The hippocampus is the part of the brain that takes current short-term memories and moves them into long-term memories. Without this crucial piece, a brain cannot make long-term memories.

Types of Memory

But this is not all they learned from Patient HM. Henry was frequently given difficult tests, like tracing shapes from their mirror images or doing crossword puzzles. He would not remember doing some of these tests, yet with each new test he became better and better. So, although he was not remembering the actions, he was still learning from them, like muscle memory.

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