Famous brain surgery patient H.M. retained a chunk of hippocampus
Amnesia probably due to the loss of other regions, connections
After a brain surgeon accidentally took away his memory in 1953, 27-year-old Henry Molaison became one of the most informative cases in psychology. For the rest of his life, the patient known as H.M. donated time to scientists who used the tragedy to study his amnesia. Now, five years after his death, Molaison is still teaching scientists about how the brain makes and stores memories.
A detailed analysis of Molaison’s postmortem brain, generously donated to scientists, reveals a surprising amount of brain tissue in the memory-forming structure known as the hippocampus, scientists report January 28 in Nature Communications. This result shows that Molaison’s severe deficits can’t be pinned exclusively on the loss of the hippocampus, as some scientists previously thought, says neuroscientist Howard Eichenbaum of Boston University, who wasn’t involved in the study.