4. Henry Molaison – The Man with a One Minute Memory
After suffering from epilepsy, Henry Molaison underwent surgery to remove a portion of his brain, including parts of the Hippocampus and Amygdala which are both vital to memory and emotions. After the surgery, Molaison’s seizures were significantly reduced but he had totally lost the ability to form new memories and retain them for more than a few minutes. While Molaison couldn’t form new memories, his old memories were intact.