In a way it is ironic, how many researchers, psychology students, and cognitive neuroscientists worldwide will remember Mr. Henry G. Molaison and he did not remember a single person he met after his brain surgery, circa 1953.

Henry G. Molaison, formerly known to all as simply HM was one of the most widely studied patients in the field of cognitive neuropsychology for over fifty years. His participation in several studies provided significant contributions to the understanding of brain function and memory. HM passed away on December 3, 2008 in Hartford, Connecticut.

Molaison suffered from seizures for many years, the cause attributed to a bicycle accident he had at the age of nine. In 1953, at sixteen years of age, Molaison underwent what would have been cutting-edge surgery at the time, at the hands of Dr. William Scoville. Scoville localized HM’s epilepsy to both medial temporal lobes. During surgery, he removed parts of the affected lobes and the majority of HM’s hippocampus, parahippocampal gyrus, and amygdala. Post-surgery, HM’s seizures were cured but he suffered from anterograde amnesia, an inability to form new knowledge and memories. However, his working and procedural memory remained intact, as did many of his long-term memories from before the surgery.

As an undergraduate student in an abnormal psychology course, our class had studied HM and his contributions to the field (as well as the fascinating case of Phineas Gage). I’d never given it much thought then, but to think of it, Molaison was studied for over fifty years! He may not have had the opportunity to live a normal life but he did selflessly partake in experiments for the rest of his life. Maybe it wasn’t selfless if he couldn’t remember what he was doing there but I can imagine the exchange between him and his caretakers:

HM, you’re here as a study patient. You can’t form new memories…

Did he have to consent to participation every day?

Thank you HM. Your participation in various studies single-handedly revolutionized our knowledge of human memory.