Henry Gustav Molaison

You have never heard of Henry Gustav Molaison. Neither had I. He died at 82 the other day, "the most important patient in the history of brain science." This provides the reason for one of the most absorbing obituaries I have ever read in the New York Times -- and The Times is famous for them.

"He knew his name. That much he could remember," begins the first-rate piece by Benedict Carey.

When Molaison -- known as "H.M." to scientists to protect his privacy -- was a young man, he underwent an operation to correct seizures, and lost the ability to form new memories. "For the next 55 years, each time he met a friend, each time he ate a meal, each time he walked in the woods, it was as if for the first time."

Yet he could remember, in detail, everything that had happened in his life up to the day of his surgery. After that, he could remember new events for only about 20 seconds before forgetting them forever.

“He was a very gracious man, very patient, always willing to try these tasks I would give him,” said one of the neuroscientists who studied him. “And yet every time I walked in the room, it was like we’d never met.”

When we get on in years, the normal forgetfulness of aging sometimes makes us fret that we're losing it. Absent the other, more ominous symptoms of Alzheimer's, we're not, really -- our short-term memories are just slowing down a tad. Nothing to worry about if we can't remember where we left the car keys. We still remember how to drive, and that's more important.

What science has learned from Henry Molaison helps give us comfort.