LINDA WERTHEIMER, HOST:
Everyone points to the Wright brothers as the inventors of human flight. But centuries earlier, it was Leonardo da Vinci who imagined human flight. He recognized how birds use lift and wing shape to glide and sketched out how humans might do that too.
Well, today, we have the story of someone you could call the da Vinci of modern brain science. NPR's Chris Benderev tells us more about him.
CHRIS BENDEREV, BYLINE: The da Vinci of brain science was, appropriately enough, also Italian. His name was Angelo Mosso. He lived in the 1800s. And until several years ago, his manuscripts were collecting a hefty layer of dust in the archives of an Italian University. Then someone opened them up and found sketches from 1882 of the first ever machine designed to watch the brain at work. It didn't look anything like a modern brain scanner.
DAVID FIELD: Looks like some kind of medieval torture device. (Laughing) I mean it's got a big strap - just kind of stopped the person moving around too much.
BENDEREV: This is David Field. He's a psychologist at the University of Reading. He's looked closely at those sketches of Angelo Mosso's machine which was called the human circulation balance. The whole thing was based on a simple idea. Your brain needs more blood when it works harder.
FIELD: He reasoned that he ought to be able to measure any net change in the volume of blood in the brain using what is essentially a lever.
BENDEREV: Here's what Mosso did. He invited people to lie down this long wooden plank which he'd carefully balanced on a fulcrum, kind of like a seesaw. Then he calibrated for anything that might throw off the balance, like the rise and fall of that person's breathing. Finally, with everything set, he'd ring a bell. Mosso figured his volunteer's brain would have to process that sound, requiring more blood, making it weigh more, which would tip the scale towards the head side. And, at least according to his manuscripts, that's exactly what happened. Stefano Sandrone, a neuroscientist at King's College London, is the man who uncovered those manuscripts, and he may just be the world's biggest Angelo Mosso fan.
STEFANO SANDRONE: It's like a romantic story, like a dream came true trying to weigh the thoughts.
BENDEREV: Mosso was trying to weigh thoughts, and Sandrone says, Mosso also figured the bigger the thought, the more it would weigh. So he'd have his volunteer read something light, like a newspaper. And Sandrone says, the balance would tilt a little bit.
SANDRONE: And then the more difficult the task became, such as reading a mathematical book or reading a philosophy book, the more the balance tilted toward the head side.
BENDEREV: That's what Mosso's documents claim. It's not exactly clear how well the balance worked. But Sandrone says, like da Vinci, Mosso had hit upon the right idea.
SANDRONE: Because it's the first proof that there is a relationship between our cognitive activities and our brain blood flow.
BENDEREV: But Russ Poldrack of UT Austin says pretty soon people starting putting too much faith in the human circulation balance.
RUSS POLDRACK: Claims were being made at the point about how, you know, this balance was going to help us understand everything we need to know about the brain.
BENDEREV: Poldrack is an expert on modern-day brain scanning technology. He says at the turn of the last century, people had unrealistic expectations for Mosso's invention, just like they sometimes have for today's brain scanners. Take, for instance, functional magnetic resonance imaging - fMRI - it's basically Mosso's dream come true.
It tells us what parts of the brain are working harder by tracking where the blood goes. And Poldrack says, to be sure, fMRI is an incredible tool. But consider how it was misused a few years back by a branding consultant.
POLDRACK: He had put people in the scanner and shown them iPhones and claimed that he saw activity in an area of their brain that demonstrated that people were in love with their iPhones.
BENDEREV: The problem - that part of the brain is also associated with pain and disgust and other emotions. The brain, it turns out, is just not that simple. But Poldrack has a guess as to why brain technology has often made it seem simple.
POLDRACK: We're sort of fascinated by seeing thought which seems so nonmaterial - seeing it as a material thing. And I think people often feel like if they see it on an imaging scan, it's real in a way that it isn't real if it's just being talked about.
BENDEREV: In the end, says Poldrack, Mosso's balance, the fMRI - they're both machines with limitations. Chris Benderev, NPR News.
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