A 3-D model of the brain of a man who lived for 55 years with almost total amnesia
is revealing new clues about what caused his memory
loss, and could lead to a better understanding of memory, researchers
Henry Molaison lost his ability to store new
memories after undergoing brain
surgery for epilepsy in 1953. The surgery was performed in the medial
temporal lobe region of the brain, including the hippocampus.
What followed is described in a new paper, published online in the journal Nature
Despite the memory loss, Molaison's language, intellectual skills,
personality and perceptual skills remained intact. The extent of his memory
loss made him a unique patient and he took part in numerous neurological
studies until his death in 2008. His case provided the first conclusive
evidence that the hippocampus plays a role in forming new memories, the study
authors explained in a news release from the University of California, San
3-D microscopic model
In 2009, researchers led by Jacopo Annese at UCSD dissected Molaison's brain
into 2 401 tissue slices that were frozen in order. As the brain was being
sliced, the researchers took digital images that have been used to create a 3-D
microscopic model of the brain.
Compared to MRI
scans taken when Molaison was alive, the 3-D model can offer much more
insight into what happened in his brain during the epilepsy surgery and how it
affected his memory, the study authors noted.
"Our goal was to create this 3-D 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 [surrounding] areas of H.M.'s
brain," Annese said in the news release.
The 3-D model has already revealed a small, previously undiscovered wound
site in the brain's left orbitofrontal cortex. It was probably caused during the
1953 surgery, Annese said.
The UCSD team has created a web-based atlas of Molaison's brain that can be
viewed using Google maps.
Read more: Past,
future may be linked in brain