A Postmortem of the Most Famous Brain in Neuroscience History

The most famous brain in neuroscience? That would belong to Henry Molaison, who died in 2008. His curious relationship with neurosurgeons began in 1953, when he underwent brain surgery to relieve frequent chronic seizures. They removed part of his brain, which cured him but left him strangely incapacitated.  

From that moment on, he was unable to create memories of any new events, names, people, places or experiences. He also lost most of the memories he'd formed in the years leading up to surgery. In the most fundamental sense possible, H.M. lived entirely in the moment.

"At this moment, everything looks clear to me, but what happened just before?" he once said. "That’s what worries me. It’s like waking from a dream. I just don’t remember." Although he interacted with the same nurses and doctors day after day, each time he saw them he had no idea he'd ever met them before. He remained a perfectly intelligent, perceptive person, but was unable to hold down a job or live on his own. Without the connective tissue of long-term memory, his life was reduced to a series of incoherent, isolated moments.

For the rest of his life, Molaison allowed scientists to study his brain, which was scanned and recorded with every advance in medical recording technology. The ultimate measurements came after his death, when it was frozen and cut into 2,401 thin slices in order to create a 3D model. That model gave researchers new insights into Molaison’s condition. For example, they found that more of Molaison’s brain had been removed than they thought. These changes to the brain could give new insights into the anatomy and the process of creating and storing memories. Read more about the research at Smithsonian.