Better known as H.M. is most neurology textbook, is an american, who suffered from severe epilepsy, in 1953 at the age of 27. To relieve his symptoms, he is required to undergo a surgery of bilateral medial temporal lobe resection. The removal included approximately one half of his hippocampus, the amygdala, and most of surrounding entorhinal and perirhinal cortex. After the surgery, his epileptic symptoms improved, but he developed profound amnesia. He has anterograde and temporally graded retrograde amnesia, although his able to recall childhood past event. He has intact perceptual, motor and cognitive function, and intact immediate memory.
In one incidence, he noticed a cup and he said “hey, I knew a fellow named John McDonald when I was a boy!”. He then described some part of the story. After being distracted awhile, he has forgotten that he had told he story, and again “hey, I knew a fellow named John McDonald when I was a boy!”
His story is one of the major discovery in knowing that medial temporal lobe and midline diencephalone structure is important in memory processing.