In 2008 the National Science Foundation (NSF) and the Dana Foundation, co-sponsored the postmortem examination of the brain of a man who was very famous on account of his memory impairment.

Henry G. Molaison, known in the scientific literature as patient H.M., underwent a temporal lobotomy in 1953 to alleviate his severe epileptic seizures; unexpectedly, the operation created a profound state of anterograde amnesia, while all other cognitive functions were preserved. His case became a landmark in the behavioral sciences because for the first time it was clear that the hippocampus and medial temporal lobe structures were essential to store and retrieve memories. 

Dr. Jacopo Annese during the dissection of H.M.'s brain.

Dr. Jacopo Annese during the dissection of H.M.'s brain.

Henry Molaison passed away in December 2008.  After five decades of speculations regarding the neurological impact of the original operation his brain could be observed directly. The goal of the project was to create a comprehensive archive containing a collection of anatomical images and histological slides, so that the plethora of behavioral and cognitive studies (cited throughout over two thousand peer-reviewed articles) could be revisited, validated, and interpreted in the light of the actual anatomical and pathological state of the brain.

The procedure was a success, but a second equally important results was also accomplished. While advancing neuroscience research we also conducted a social experiment that would transform the way science is communicated to the public: we broadcast the entire slicing procedure 'live', on the web. As a result, over 400,000 viewers tuned in and witnessed the dissection over a period of four days and three nights, sending comments and questions via Facebook and Twitter. Here we publish, for the first time since the experiment was performed in 2009, a sample of the original twitter messages that were posted by the viewers of the dissection by Dr. Annese. One example below:

Q&A Post-it® notes written by Dr. Annese during the procedure.

Q&A Post-it® notes written by Dr. Annese during the procedure.

"Dissection of the brain of a famous memory loss patient; live feed: I can't get enough of this! 12.4.2009"

Not being able to use a keyboard while busy Dr. Annese responded using Post-it® notes that he wrote while cutting the brain. This unusual method of posting on the web was later named: ‘analog twitting’.

We published the results of our study in the journal Nature Communications in January 2014. In this article we demonstrated that in fact, half of H.M.’s hippocampus had survived the 1953 surgery. This has very deep implications on past and future interpretations of H.M.’s neurobehavioral profile and of the existing literature where H.M. is described as a ‘pure’ hippocampus lesion patient. In the light of these surprising findings it is crucial to revisit raw data from behavioral testing.  We also discovered a discrete lesion in the pre-frontal cortex that was never suspected.  We used the 3D virtual model of the brain to reconstruct the dynamics of the surgery and established that the brain damage above the left orbit was plausibly created by Dr. Scoville when he lifted the frontal lobe with his spatula, in order to reach into the medial temporal lobes.

The article also describes the general neuropathological state of the brain via multiple imaging moralities. H.M. was 82 when he died, naturally the brain had aged considerably and it shows several pathologic features, some severe, that contributed to his cognitive decline.


H.M.'s Brain Atlas

The goal of Project H.M. was to create an 'open source' model of the brain that could be shared not only with the scientific community but also with non-experts, members of the public who are interested in neuroscience and know the story of patient H.M.

We are honored to offer this resource publicly and freely to scientists and the curious at large; help us keep things this way by contributing financially to the project. Support Project H.M. here.

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