John Thorndike | The Last of His Mind |

Henry Molaison

I first read about the famous patient H.M. in David Shenk’s book The Forgetting. Shenk describes how in 1953 the well-known brain surgeon William Beecher Scoville, in an attempt to relieve his patient’s seizures, removed two sections of H..M.’s brain. The seizures abated, but with them went the ability to store any new memories. As Shenk wrote about H.M., “For the rest of his long life, he was never again able to learn a new name or face, or to remember a single new fact or thought.”


A year ago, H.M. died, and his name was revealed to the public: Henry Molaison. He had lived near Hartford, Connecticut, first with his parents and then in a home, for over fifty years. From what I’ve read he was not an unhappy person. He was much liked by those who took care of him, and by the many doctors who studied him. Even when alive, his brain became the most studied brain in history—and now, the New York Times reports, that brain has been flown across the country to a lab in California, where it will be shaved into 2500 slices, all to be analyzed minutely.

The Times reports that Dr. Scoville “suctioned out two slug-sized slivers of tissue, one from each side of the brain.” A more complete description is offered in Philip J. Hilts’ book about H.M., Memory’s Ghost: “Dr.Scoville inserted a silver straw into Mr. M.’s brain and sucked out nearly the entire grayish-pink mass of the hippocampus and the regions leading up to it. On both sides. He drew out altogether a fist-sized piece of the center of the brain.”

The hippocampus, often described as having the form of a seahorse, is a paired structure, lying in both the left and right sides of the brain, nestled deep within the temporal lobe. In early childhood, as the brain develops, the hippocampus is the last part of the brain to gain a protective myelin sheath to its neurons. It is the hippocampus that enables current thoughts and impressions to be saved as memories, and because it is so slow in maturing, few humans can remember much before the age of three.

With encroaching dementia, the hippocampus is also one of the first parts of the brain to have its myelin stripped—which is why memory loss is almost always the first sign of encroaching Alzheimer’s.

None of this can be studied in vivo, and Dr. Scoville’s operation today would raise a howl of protest. Yet much of what we know about the process of memory comes from the studies on the unfortunate Henry Molaison. He stands as a kind of ultimate dementia patient, whose short-term memories were almost entirely wiped out one day in 1953. I think about this man—only twenty-six when he became, in effect, frozen in the present. He remained part of the human family, of course. But I think of how his parents must have felt, to find that their son had disappeared, that the rich bath of memories we all depend on had been entirely stripped from him.

I look at his photo, taken years after the operation. He seems mild, congenial, benign. A little like my father, but without any edge. Because I know what happened to his brain, I find it a terrifying portrait..

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