Henry G. Molaison (H.M.) was one of the most studied patients of his time in the neuroscience world; and his brain is still revealing valuable information to this day.
Researchers created a microscopic anatomical model of H.M's brain postmortem including 3D measurements of the temporal lobe, a University of California, San Diego Health Sciences news release reported.
H.M. was epileptic and also suffered from severe amnesia from a bilateral surgical ablation of the MTL (including the hippocampus) back in 1952; he passed away in 2008.
The patients' "personality, language and perceptual skills" remained intact, but he did not have the ability to hold information in his long-term memory.
His case provided "the first conclusive evidence for the involvement of the hippocampus in forming new memories," the news release reported.
After the patient's death researchers preserved 2,401 thin brain tissue slices. As they dissected the brain they took images that were later used to create the 3D model.
"Our goal was to create this 3D model so we could revisit, by virtual dissection, the original surgical procedure and support retrospective studies by providing clear anatomical verification of the original brain lesion and the pathological state of the surround areas of H.M.'s brain," study leader Jacopo Annese, PhD, at the University of California, San Diego, said in the news release.
The team found a "a small, circumscribed lesion" in H.M's left orbitofrontal cortex that had not been detected in the past. The lesion may have been formed during the 1952 surgery, which could have contributed to the patient's condition.
"The findings reported in Nature Communications constitute new evidence that may help scientists today understand more fully the consequences of H.M.'s operation in the context of modern knowledge on memory of the functional anatomy of the hippocampus," the news release reported.
The team also created an online atlas of H.M's brain.
