Henry Molaison, aged 27, had surgery to alleviate his severe epileptic seizures in 1953. During the operation, part of the temporal lobe on both sides of his brain was removed, suctioning out most of his hippocampus, a seahorse-shaped structure now known to play a crucial role in forming memories. The operation cured his epilepsy, but caused anterograde amnesia, impairing his ability to form long-term memories.
The neuropsychologist Brenda Milner, credited by many for creating the field of cognitive neuroscience, was the first researcher to conduct rigorous testing on Molaison, famously called HM in popular literature and medical texts. Her groundbreaking observations of HM and others revolutionised memory research and our understanding of memory networks. At the age of 97, Milner continues to work as a professor in neurology and neurosurgery at McGill University’s Montreal Neurological Institute. Here, she retraces her early work on memory and its implications.