Question

Who was Henry Molaison? What happened to him? Describe the nature of his memory impairment. That is, what aspects of his memory were damaged? What aspects were preserved?

Answer 1

HM lost his memory after surgery was performed to treat his epileptic seizures when he was 27 years old. The operation was successful as he didn’t suffer from seizures hence forth, but lost his memory. This was become during surgery, parts of the temporal lobe was removed such as the hippocampus and part of amygdala from both sides of the brain. However, after surgery HM suffered from severe amnesia. He suffered from retrograde amnesia as could remember his childhood memories, but couldn’t remember the memories of recent years up to 11 years that led to the surgery. HM also suffered from severe anterograde amnesia which is difficulty in forming new memories. His short term memory was fully functioning; however, he was unable to transfer the information to the long term memory. He didn’t have any knowledge of current affairs as he could not remember the news after reading the paper. although he could remember people from his childhood, he didn’t remember anyone he encountered post the surgery. He has the ability to learn new motor skills but did not remember learning the skills as it was at a subconscious level. For example, HM started to learn how to walk using a walking frame, after he sprained his ankle. He got better at walking with practice, however, could not remember walking with the walking frame.