Henry Molaison

Henry Gustav Molaison, widely known as H.M., was born on February 26, 1926. His life took a dramatic turn when, at the age of ten, he began experiencing minor seizures, which escalated to major seizures by the age of sixteen. Despite being treated with high doses of anticonvulsant medication, his condition remained debilitating. In 1953, at the age of twenty-seven, he underwent a groundbreaking surgical procedure known as a bilateral medial temporal lobectomy, performed by neurosurgeon William Beecher Scoville. This surgery aimed to alleviate his epilepsy by removing parts of his brain, including the anterior two thirds of his hippocampi and other critical areas.

While the surgery partially succeeded in controlling his seizures, it resulted in a profound and life-altering side effect: H.M. became unable to form new memories. This unexpected outcome transformed him into a pivotal figure in the field of neuroscience. From late 1957 until his passing in 2008, H.M. was the subject of extensive research, providing invaluable insights into the relationship between brain function and memory.

H.M. resided in a care institute in Windsor Locks, Connecticut, where he became a focal point for ongoing investigations into cognitive neuropsychology. His case significantly contributed to the understanding of how specific brain structures relate to psychological processes, shaping theories that continue to influence the field today.

After his death on December 2, 2008, H.M.'s brain was preserved and studied further. It was kept at the University of California, San Diego, where it was meticulously sliced into histological sections. In 2014, a brain atlas constructed from his brain was made publicly available, ensuring that his legacy would continue to inform and inspire future research in neuroscience.