Medical Folk Figure. In the medical community around the world he was better known as the amnesiac HM. The study of his condition revolutionized our understanding of human memory and learning. In 1953, Molaison underwent experimental brain surgery where his Hippocampus was removed to stop recurrent seizures, but the surgery had the unfortunate side effect of wiping out his ability to form new memories. Molaison's memory was basically frozen on the day of his surgery when he was just 27. He would never be able to form new memories again. For the rest of his life each time he met a friend, each time he ate a meal, each time he walked in the woods, it was as if for the first time. In a well documented experiment with HM, he was tested to determine how memory affects appetite, showing that our feeling of satiety is largely tied to our memory of having recently eaten. A few minutes after HM had consumed a full meal, he was presented with another meal and told that it was his meal-time. He happily chomped it down. The researchers tried it once more, and got the same reaction. Only after his third meal did he begin to feel full. His amnesia did not damage his intellect or radically change his personality, but he could not hold a job and lived completely in the moment. He lived with his parents, and later with a relative through the 1970s. He helped with the shopping, mowed the lawn, raked leaves and relaxed in front of the television. He could navigate through a day attending to mundane details like fixing a lunch or making his bed by drawing on what he could remember from his first 27 years. Outliving his family members, he moved into a nursing home in 1980 where he resided for the rest of his life. Through study of what had been lost and what had been spared, Patient HM went on to become the most famous case study in neuroscience, and interest in him has remained very high for over 50 years. Just hours after his death, scientists worked through the night taking exhaustive MRI scans of his brain, compiling data that will help tease apart precisely which areas of his temporal lobes were still intact and which were damaged, and how this pattern related to his memory. Like Einstein, his brain has been preserved for future generations of scientists to study. The Brain Observatory at the University of California in San Diego, after a year of preparation, will dissect the brain which has been kept at 70 degrees below zero Celsius into 2600 slices each 70 microns thin. Henry Gustav Molaison left no survivors when he died of respiratory failure, but he left a legacy in science that cannot be erased.