The Hippocampus Patient Henry Molaison had his hippocampus and adjacent structures of the medial temporal lobe (indicated by the shaded area) surgically removed to stop his epileptic seizures (left). As a result, he could not remember things that happened after the surgery. Henry (right), better known to the world as patient H.M., passed away on December 2, 2008, at the age of 82 at a nursing home near Hartford, Connecticut. Henry’s catastrophic inability to encode new long-term memories was discovered by Montreal psychologist Brenda Milner in 1953, and Molaison participated in countless memory experiments between that time and his death. In so doing, he made fundamental contributions to our understanding of memory and the brain.