Henry Molaison, HM for short, wanted to be a brain sur­geon as a kid. Instead he spent his life as a research sub­ject after an exper­i­mental surgery on his own brain left him inca­pable of forming new memories.

Over the weekend I got to see the last per­for­mance of Yes­terday Hap­pened: Remem­bering HM at the Cen­tral Square The­ater. The play was an inter­dis­ci­pli­nary col­lab­o­ra­tion between MIT’s play­wright Wesley Savick and com­poser Tod Machover and Northeastern’s scenic designer Justin Townsend. It was an  extra­or­di­nary example of how art can be used to com­mu­ni­cate science.

HM devel­oped severe epilepsy as a teenager. In an attempt to cure this dis­ease, doc­tors decided to remove his hip­pocampus, his parahip­pocampal gyrus and his amyg­dala, having absolutely no clue how such a pro­ce­dure would affect his mind.

As may seem obvious to us today, the surgery affected HM’s mind quite a bit. Every day he woke up not knowing where or how old he was, whether his par­ents were alive or dead, or the names of the nurses who had spent years taking care of him. He did seem to retain a sense that his con­di­tion was helping other people somehow. And he never lost the ability to do cross­word puzzles.

The play was, as I said, extra­or­di­nary, some­thing of an exper­i­ment itself. Since our man Townsend took care of the set design…and since it was so almost another char­acter in the play, I’m going to describe it to you now: Audi­ence mem­bers sat around three sides of the stage, which was just an open floor in the middle of a big room. On the fourth side an image of HM as a young man was pro­jected onto a white wall. Above Henry’s por­trait, var­ious other images were pro­jected throughout the show. In the middle of the floor rested an enor­mous white box lit up from the inside. On either side, a row of hor­i­zontal flu­o­res­cent lights sat a few feet above the ground while dozens of indus­trial light bulbs hung from the 40-​​ft-​​or-​​so ceiling. At the back of the stage, on either side of the pro­jec­tion wall, were two tall rolling ladders.

The story took a cir­cuitous path to tell Henry’s story, starting out with HM under­going a med­ical inqui­si­tion, the simul­ta­neous onslaught of ques­tions repeated day after day for decades. It wan­dered through his expe­ri­ences of dressing, sleeping, and doing the cross­word puzzle. People in his life came on and off stage to tell the audi­ence what they knew about him, the kind, smart man “with a very bad memory.” These were doc­tors and school­mates and nurses and even “actors” audi­tioning  for the part of Henry in Remem­bering Yes­terday.

The smart man with a very bad memory, Henry used logic and rea­soning to under­stand the world around him that could have been an eternal void. It was at times; he said there were holes, gaps in his mind. But his rational skills seemed to have saved him, in a way. This was par­tic­u­larly clear when the char­acter vocal­ized his expe­ri­ence of doing the cross­word puzzle — a process of trial and error, elim­i­na­tion and nega­tion. While he may forget what ques­tion he was working he could even­tu­ally reason his way to its answer.

One of the most curious things about Henry’s con­di­tion was that, while he couldn’t form new episodic mem­o­ries (nor recall any from before the surgery), he could form func­tional ones. While he couldn’t learn new names he remem­bered his own and those of people in his life before the acci­dent. He remem­bered how to tie his shoes, how to speak and how to do a cross­word puzzle but he couldn’t remember what he’d eaten for break­fast any given morning or what season it was.

Clearly the brain is a pretty com­plex machine. There isn’t just one kind of memory. Each behaves slightly dif­fer­ently and lives in its own part of the brain. To us, today, that’s not so exciting or sur­prising. But before 1957 sci­en­tists didn’t know any of that. They had their sus­pi­cions, said one of the char­ac­ters, but until HM there was no con­clu­sive evi­dence about how the brain worked. The fact that lan­guage is stored in one area and sight in another, for instance. The fact that long term mem­o­ries and short term mem­o­ries live in sep­a­rate areas. The fact that episodic memory is dif­ferent from func­tional memory. All of those are new in the last sixty years.

When HM died in 2008 another sur­geon removed his brain which now resides at UC San Diego, thou­sands of slices pre­served in a solid polymer. His brain con­tinues to inform sci­ence, per­haps a bigger feat than if he’d gone to med­ical school and become a surgeon.

Oh one more thing. When I said he couldn’t remember any episodes from his pre-​​surgery life, that wasn’t entirely true. He did remember one single event: the day he got to go up in an air­plane and see the world from above. He called it the high point of his life and he remem­bered it always, indi­cating that a memory’s sig­nif­i­cance may send it to a dif­ferent part of the brain.

Photo by A.R. Sin­clair pho­tog­raphy.