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What happens when you remove the hippocampus? - Sam Kean

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TEDEd Animation

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When Henry Molaison (now widely known as H.M.) cracked his skull in an accident, he began blacking out and having seizures. In an attempt to cure him, daredevil surgeon Dr. William Skoville removed H.M.'s hippocampus. Luckily, the seizures did go away — but so did his long-term memory! Sam Kean walks us through this astonishing medical case, detailing everything H.M. taught us about the brain and memory.

Once Dr. Scoville removed H.M.’s hippocampus, Henry’s brain could no longer perform memory consolidation. How did Henry’s life change? Do you think it affected his quality of life? Was the cost to Henry’s memory worth the benefits to his health?

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Sam Kean
  • Director Anton Bogaty
  • Narrator Addison Anderson

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