Two very special patients have helped doctors study memory and the hippocampus in recent years. These two men are referred to only as EP and HM, and each of them suffered memory loss after the loss of this particular section of the brain. HM suffered a head injury as a child and later underwent experimental brain surgery to remove most of his hippocampus. EP, in contrast, contracted a disease that ate away much of his hippocampus. Both men are now unable to form new memories, but they can remember some things from before their traumas.For example, both EP and HM are likely to recall things they learned in school or family memmories from their youth, but both will also always think it's the first time they've met you, no matter how many times you may have met previously.