Henry Molaison fell off his bicycle when he was 7 years old, injuring his head.
He began to have epileptic seizures when he was 10. Seizures became a normality. Scoville performed an experimental surgery on H.M.’s brain to stop the seizures. Specifically he removed parts of HM's temporal lobes (his hippocampus along with it). The hippocampus controls the long-term memory in the brain.
This removal resulted in Molaison losing all his LTM related to stored and factual memories. The seizures stopped but H.M. suffered from amnesia for the rest of his life. After his accident, Molaison had a case of anterograde amnesia. Anterograde amnesia is the loss of ability to create new memories after the event that caused the amnesia. In this case, the term anterograde amnesia is not totally applicable. But, the event would be the surgery leading to inability to recall past events while the long-term memories of movement remain intact.
