Henry Molaison had one of the most unique brains known to neuroscience. Now, six years after "H.M.'s" death, his brain has been sliced, digitized, uploaded, and made available to scientists for further study.
Back in 1953, surgeons performed an operation on Molaison in an effort to alleviate his terrible seizures. A team led by William Beecher Scoville removed pieces of the temporal lobes above his ears — and, regrettably, critical portions of the hippocampus. The seizures settled down, but it came at a terrible price: Permanent amnesia. Afterwards, Molaison could only remember events that happened before his surgery.
Known as H.M. in the journals, he participated in hundreds of studies. Remarkably, despite having no short term memory, he could learn new motor memory tasks and exhibit normal intelligence. After his death in 2008, his brain was donated to science. Until very recently, it just sat in a standard formaldehyde buffer.
The latest chapter in this story involves neuroanatomist Jacopo Annese and his efforts to preserve the brain even further. Writing in National Geographic, Virginia Hughes explains:
On the one-year anniversary of H.M.'s death, Annese's team froze his entire brain as a single block and began a 53-hour process of cutting it into some 2,400 super-thin slices. "I didn't sleep for three days," Annese says. He had a team of students that took shifts to help him — and to make sure he stayed awake. "There was always one person next to me, and if I looked like I was phasing out or missing a slice, the code word was 'prosciutto'," says Annese, who is Italian. "It was probably the most engaging, most exciting thing I've ever done."
Annese's team live-streamed and Tweeted the entire procedure, and he says some 400,000 people tuned in to watch. In the end, just two slices were damaged while cutting.
A camera mounted above the iced brain took a high-resolution picture of each slice. These images became the basis of a digital, interactive atlas of H.M.'s brain, as Annese and Corkin describe today in Nature Communications. The atlas will be made available to any other researcher interested in collaboration, Annese says.
Here's a clip of the cutting procedure:
You can check out one slice of the atlas here. According to the new scans, H.M. retained about 50% of his hippocampal region, revealing the importance of this area to memory and the multifaceted way in which it works.
This procedure is very reminiscent of the ultra-high resolution 3D scanning that's being done as a part of the BigBrain project. It's also a precursor to even higher resolution scanning techniques that could actually preserve the very essence of the person itself — information that could result in the reanimation of an individual after death in a digital substrate.