As a young kid, Henry Gustav Molaison also famously known as H.M, was riding his bike and got hit by a car. This traumatic event caused petit mal and grand mal seizures daily. Petit mal seizures can cause uncontrollable, rapid eye movement, and mal seizures can cause drop attacks, which make a person fall to the ground. Because of these seizures, H.M wasn’t able to have a normal childhood or any life at all. At age 27, he met Dr.
William Scoville, who believed she could alleviate the symptoms of the seizures by dissecting H.M’s hippocampus. They didn’t know it at the time, but this surgery would not only change H.M’s life but also the future in neuroscience.
After the surgery, H.M was left with no seizures but couldn’t form any new memories. H.M could recall everything eleven years before the surgery and most of his childhood. Unfortunately, he could not form memories or anything at all.
He didn’t have access to his declarative memory. He had what doctors call anterograde amnesia, which is the inability to form and remember new memories.
Due to H.M’s condition, he became one of the most studied humans in history. He was studied for over 40 years. He was able to consent to the constant testing because he didn’t fully understand his condition. Because he had long-term memory impairment he wouldn’t be able to remember all the previous sets and therefore he wasn’t completely able to understand what he was agreeing to.
Susan Corkin was his guardian and overseer in research. She worked with H.M for 46 years. She made sure the staff gave him frequent breaks and asked him if at any moment if he was uncomfortable with the testing. By giving him frequent breaks, he would not be able to determine how much had passed.
When H.M passed away, there was a custody war between Dr. Corkin and Jacopo Annese. They agreed to transfer the brain to David Amaral. Dr. Amaral was expected in medial temporal lobe anatomy. H.M’s brain is now kept at the University of California, San Diego, USA. It is sliced up into histological sections.
H.M’s study was very important because it’s the first strong evidence for the role of the medial temporal lobe structures. Through this, they found out that it is critical for binding memories and the consolidation of the short-term memory into the long-term memory. It also showed that memory was dissociable from other cognitive abilities.