SCOTT SIMON, HOST:
If you dig into an archaeological site - and who among us hasn't? - you may uncover ancient human teeth and bones. But scientists are also finding brains. Unlike skin, muscle and other soft tissue, human brains seem to endure. Alexandra Morton-Hayward joins us. She's a paleobiologist at Oxford University - joins us from Oxford. Thanks so much for being with us.
ALEXANDRA MORTON-HAYWARD: Thank you so much for having me, Scott.
SIMON: I gather your research paper says more than 4,400 preserved human brains have been discovered across much of the world?
MORTON-HAYWARD: Yeah. That's it - worldwide, every continent except Antarctica. And the reports we found date back to the early 1600s.
SIMON: How have they been preserved?
MORTON-HAYWARD: So we identify five different types of preservation. Dehydration, freezing, tanning, for example, are well-known to most folks. We also identify an unknown mechanism of preservation that seems to be unique to the brain. These brains are the only soft tissue preserved amongst otherwise skeletonized remains - so just a brain rattling around in a skull, which is super weird.
SIMON: Oh, mercy.
MORTON-HAYWARD: It's mind-blowing, right?
SIMON: As it were, yeah, interesting. What does a preserved brain look like?
MORTON-HAYWARD: Oh, they're fantastic - so invariably shrunken, usually to around a fifth of their volume in life. So they look kind of like a large walnut. They sit perfectly in the palm of your hand.
SIMON: Oh, I'm sorry. That suggests you've held one in the palm of your hand.
MORTON-HAYWARD: Oh, absolutely. We have a collection here in Oxford of more than 570 brains of this unknown preservation type, so the ones that are super mysterious. We've got 4 1/2 fridges full of the things, so I'm always handling them. I'm always opening the fridges, checking how they are and having a little chat to them and all sorts as I'm puttering about the lab. They tend to be kept in sort of jam-jar-size containers, and we have so many at the moment that we're almost having to tape them in to the shelves so that they don't jostle about when we open up the doors.
SIMON: What can we learn from ancient human brains?
MORTON-HAYWARD: That's my favorite question. So archaeological science has seen this huge explosion in the amount of information we can glean from biomolecules that are recovered from ancient tissues - things like ancient DNA and proteins and lipids. And these brains seem to be a really rich reservoir of those molecules. And soft tissues are much richer source of these molecules in life because they're more metabolically active than the hard tissues, for example, like bone. So they're a really promising treasure trove of archaeological information.
SIMON: Like what?
MORTON-HAYWARD: There's a lot of work in paleopathology looking at ancient proteins as markers of nutritional status - the richness or poorness of one's diet. We can look at metabolic disorders, even the possibility of looking at neurological disorders in these particular brain remains. But we can study all sorts of things from past pandemics to whether an individual might have had a bit of a dodgy ticker.
SIMON: (Laughter) The dodgy ticker shows up in the brain?
MORTON-HAYWARD: That's it. Population and individual level, you name it, we can investigate it with ancient proteins.
SIMON: Have you, you know, discovered Julius Caesar's brain or...
MORTON-HAYWARD: Ooh, good question. So there are some famous ancient royals. There are some Egyptian royalty as well. But we also have brains from the down-and-outs. We have 80 criminals who were thrown into a well in the Middle Ages, for example. So it's a real cross section of society.
SIMON: Those are my ancestors, by the way...
MORTON-HAYWARD: (Laughter).
SIMON: ...The criminals thrown into the well. I bet if you can read their brains, they'd say, you know, I'm a Simon. But...
MORTON-HAYWARD: (Laughter).
SIMON: ...This is fascinating work. How did you decide to go in this direction?
MORTON-HAYWARD: I think it kind of found me rather than the other way around. I worked for years as an undertaker and embalmer, so I've always worked with the deceased. And I was so fascinated by decomposition that I wanted to study it at a scientific level.
SIMON: This sounds like fascinating work. What more do you think we can learn from it?
MORTON-HAYWARD: Oh, I think this is just the beginning. My Ph.D. really focuses on nailing down what this mechanism of preservation that seems to be unique to the brain is. Once we know why brains persist when other organs perish, we can do all the exciting work that we were chatting about earlier.
SIMON: Alexandra Morton-Hayward, paleobiologist at Oxford University. Thank you so much for being with us.
MORTON-HAYWARD: Thank you, Scott. Transcript provided by NPR, Copyright NPR.
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