HM - A Case Study in Memory

Professor Howard Eichenbaum outlines the importance of HM to memory research. Following his death in December 2008, HM's real name was revealed as Henry Gustav Molaison.

HM is probably the most famous neurological patient there’s ever been. The reason why he was important has to do with both the selectivity and severity of a memory disorder that was created in HM when they removed, when surgeons removed, the medial parts of the temporal lobe which include the hippocampus and the surrounding cortex. This patient suffered a rather severe form of epilepsy which couldn’t be treated by drugs. So as a rather heroic and experimental approach they tried removing the cortical areas that were involved, including the hippocampus and surrounding cortex. Subsequently, and to the surprise of the surgeon, he suffered this very severe amnesia, which has pretty much told us the story we now have to explain about how memory works.