Zapping Nerves Into Regrowth

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, a look down the track for high speed rail in the US and why painting wind turbine blades black could save birds. But first, some hopeful news for people with spinal cord injuries this week.

Results of an early trial published this week in the journal Nature Medicine show some improvements in arm and hand function after people received electrical stimulation near the site of their spinal cord injury. Sophie Bushwick, senior news editor at New Scientist, is back to tell us more. Hi, Sophie.

SOPHIE BUSHWICK: Hi, Ira.

IRA FLATOW: This is really exciting. Tell us more about this spinal cord research.

SOPHIE BUSHWICK: Yeah, this is a really great intervention because these are external pads that are placed on the skin near the site of the spinal cord injury. And the participants in this trial received electrical stimulation from the pads while they were doing physical therapy to improve hand and arm function. And more than 2/3 of those who tried it said they had a significant improvement in their ability to grasp things and to move their hands after they had this treatment.

IRA FLATOW: That’s a lot of people, isn’t it?

SOPHIE BUSHWICK: Yes, and gains like that for someone who maybe is suffering from paralysis or other problems from their spinal cord injury can really be life-changing. It suggests also that they might have nerves regrowing as a result of this therapy because even after the pads were removed, they continued to have this improvement. So they didn’t have to be actively receiving the electrical stimulation to benefit from it.

IRA FLATOW: That is really amazing. Now, is this something that could help all kinds of spinal injuries?

SOPHIE BUSHWICK: Well, this only applies to certain kinds. So this isn’t going to be suitable for everybody. There needs to be parts of the spinal cord remaining intact in order for this nerve regrowth to happen. But about 2/3 of people with spinal injuries have the kind of injury that could benefit from this type of treatment.

IRA FLATOW: Hm. Usually, you know, when we talk about severe spinal cord injury, it’s in the context of getting people to walk again. But here, they’re looking at hands. And that’s important also, right?

SOPHIE BUSHWICK: Right, that’s a big quality of life issue. You know, for me, I’m someone who doesn’t have a spinal cord injury. I don’t know what it’s like for someone in this. But participants in the trial have said that hand and arm function is really huge in terms of improving their quality of life while they’re living with this type of injury.

IRA FLATOW: Yeah, I can imagine that. OK, let’s move on to a different kind of zap, and I’m talking about the X-ray laser at California SLAC National Lab has fired the most powerful X-ray pulse ever reported. Wow.

SOPHIE BUSHWICK: Yeah. You know, this pulse exists in only a few hundred billionths of a billionth of a second. And in that time, it has about a terawatt of power going. So that’s 1,000 times more than the average yearly output of a nuclear power plant.

IRA FLATOW: You know, it just seems amazing how you can pack thousands of power plants into one zap.

SOPHIE BUSHWICK: It’s super cool. And the reason they want to do it is, you know, this isn’t going to be like a pew pew laser situation. This is going to be so they can peer into these teeny little details of materials– you know, look at the behavior of electrons and molecules on this incredibly tiny scale. That’s the kind of research that the super powerful X-ray pulse can enable.

IRA FLATOW: Right, not to be confused with lasers used for fusion, right? This is not fusion research.

SOPHIE BUSHWICK: That’s right. This isn’t going to be powering our homes anytime soon. But it could be unraveling some, you know, fundamental mysteries of the universe.

IRA FLATOW: OK that’s good too, right?

SOPHIE BUSHWICK: I like it too.

IRA FLATOW: Yeah, I do. Yeah, let’s move on to some other tech news. OpenAI got into some trouble this week for the voice used in one of its products and a conflict with actress Scarlett Johansson. But there’s other ChatGP2 news as well, right?

SOPHIE BUSHWICK: That’s right. In one study, researchers were looking at how ChatGPT gives housing advice. So if you’re a potential home buyer, where does it advise you to live? And they found racial bias in the suggestions from the chat bot. People who were Black were more likely to be recommended to live in poorer neighborhoods, and people who were white were recommended to live in more wealthy ones.

IRA FLATOW: Now, is this just another typical case of these models reinforcing existing biases?

SOPHIE BUSHWICK: That’s exactly right. So this study, they looked at three US cities, Chicago and New York City, which are relatively segregated, and then San Antonio, Texas, which is more integrated racially. And the Chatbot that racial bias had exhibited was stronger in Chicago and New York City as opposed to the more integrated city of San Antonio.

IRA FLATOW: Now, I’d like to know how the model knows if someone was Black to guide them toward certain housing areas.

SOPHIE BUSHWICK: Well, in this particular study, the researchers just entered profiles of people. So they had people tell the chat bot what race they are, what gender they are, what their wealth is, you know, their socioeconomic status, and then ask for recommendations. But, you know, these bots are trained on all this past data, and our past data, our existing data, it encodes a lot of bias– you know, racial bias, bias based on gender, ageism– and it can come out in weird ways. So, for instance, a previous study found that when asked to judge people who spoke either African-American Vernacular English or standard American English, the bots showed bias against the people who spoke AAVE. So it’s almost like this constant battle to make sure that we’re seeing all the potential harms of these bots and that companies are constantly working to try to remove them.

IRA FLATOW: Well, is anyone actually planning to use ChatGPT or other AI products for real estate? Is this a real problem as we speak.

SOPHIE BUSHWICK: Oh, it definitely is. In 2023, two real estate platforms, Zillow and Redfin, did offer these ChatGPT plug-ins to have recommendations, and they had to remove them after a month because they flagged issues with the ability of these bots to meet Fair Housing standards.

IRA FLATOW: Yeah, you know, I love a good microbiome story. And you have one this week about the scalp microbiome. Who knew? But I guess I would have suspected.

SOPHIE BUSHWICK: That’s right. The scalp has a microbiome just like the skin does. And then researchers use that information to find a potential treatment for dandruff.

Often when people who have dandruff have a lot of this particular species of fungus, malassezia restricta, and that makes the cells on your skin of your scalp clump together and form those, you know, pretty telltale white flakes. And, you know, a lot of people who have this issue, they’ll use chemicals that treat the fungus. But then the fungus just comes back. So instead, the researchers had a bunch of volunteers wash their hair, and then they tested their scalp microbiome and compared the scalps of people who had dandruff and people who didn’t. And people who were not prone to dandruff had a lot of this bacteria called cutibacterium acnes, which, as you might guess from acne–

IRA FLATOW: Right.

SOPHIE BUSHWICK: –when it’s on the rest of your skin, it causes acne. It can cause real problems. But on the scalp, it seems to have this protective effect against the fungus that causes dandruff.

IRA FLATOW: No kidding. That is amazing. So I’m picturing some day where we’ll see ads on TV for acne bacteria in your shampoo, right?

SOPHIE BUSHWICK: Well, what they did is instead of putting the bacteria itself in the shampoo, they developed this lotion that contains propionic acid. That’s an acid produced by these acne bacteria. And volunteers who used it on their scalp said that it did help treat their dandruff.

IRA FLATOW: So this could be actually an actual product.

SOPHIE BUSHWICK: Oh, for sure. You might not be able to find it in the drugstore today, but maybe down the line we’ll all be, you know, taking a leaf out of the acne bacteria book.

IRA FLATOW: I’m waiting. Next up, some pretty epic dress-up play involving Greek armor? What’s this about?

SOPHIE BUSHWICK: I love this study. So there’s this famous suit of armor called the dendra armor. It’s about 3,500 years old, and it’s one of the oldest complete suits of metal armor from the Bronze Age.

And this is from bronze age Greece. Researchers were like, this is a really heavy, bulky suit. Could warriors actually wear it in sustained combat, or is it more of like a ceremonial outfit that they would have worn for decoration?

IRA FLATOW: Yeah. So what did they find out?

SOPHIE BUSHWICK: So what they found out is if you put replicas of this armor on modern Greek soldiers– they had the Hellenic Marines volunteer to help test this. And then they had them do 11 hours of these activities inspired by descriptions of combat in Homer’s Iliad. And they found that they held up pretty well.

You know, the soldiers were tired at the end of the day after a long day of hitting a shield with a replica sword or a spear. They used bows and arrows and rocks. They even rode on chariots.

And they had them do all these exercises for 11 hours. They had them eat a menu of foods inspired by this era of history. And then afterwards, they were OK.

IRA FLATOW: Somewhere, there’s a video of this that we’re all going to want to see.

SOPHIE BUSHWICK: Oh yes. If you’ve ever wanted to see someone riding a chariot that’s on a treadmill, you definitely want to check out the video of these exercises.

IRA FLATOW: Yeah, so they had no meals ready to eat in this fight. They had real–

SOPHIE BUSHWICK: No, actually, their meals sounded really good. They had these a heavy breakfast and a heavy dinner with snacks in between, and the food included bread. They had red wine with both of their big meals. They had goat cheese and onions. It sounded much better than an MRE.

IRA FLATOW: The idea of all these combat moves is coming out of Homer.

SOPHIE BUSHWICK: Well, Homer is– he was actually putting these stories down hundreds of years after the events he’s describing. So he’s not exactly the most reliable source, but we just don’t have a ton of firsthand information about that era. And we do think that battle was sort of like today’s high intensity interval exercises.

You know, the soldiers would go to battle, and they’d have maybe an intense fight, and then they’d retreat back behind their battle lines to rest and to have a snack. So Homer’s not an ideal source, but he is a potential source. And by putting these soldiers through these paces, it is really a rigorous study for exercising a lot under these conditions and seeing how people hold up while they’re wearing something really bulky like that armor.

IRA FLATOW: So they did conclude, then, that this armor is actually useful. It just doesn’t weigh them down. It actually could be useful in battle conditions.

SOPHIE BUSHWICK: Yes, they were monitoring the volunteers throughout, testing their body and skin temperature, taking blood samples, measuring how much energy each of these exercises was expending. And using computer models afterwards, they found that this could be sustainable for an 11 hour combat period. Unless the weather was extremely bad and extremely hot, your average elite Mycenaean warrior would definitely have been able to wear this.

IRA FLATOW: Yeah, I get that, considering our summer coming up here.

SOPHIE BUSHWICK: Yes.

IRA FLATOW: Finally, giving people owl vision– I mean, a 360 degree view. How does that work?

SOPHIE BUSHWICK: This is amazing. So basically, volunteers were wearing a VR headset. And on top of their head, they had a 360 degree camera.

And the way that this software worked was when a volunteer turned their head slightly, the VR view would give them an even bigger turn than they actually did. So when they turned their head sort of 90 degrees to the side, their view in the VR headset was behind them, 180 degrees behind them.

IRA FLATOW: I would imagine it would take some time to adapt to this, right?

SOPHIE BUSHWICK: Definitely. It did take a little while. But then people, once they had adapted, were really comfortable with this owl’s eye view. You know, they were able to navigate and to pick things up. And then when it was time to take the headset off after that, they had a little bit of trouble readjusting back to normal human view.

IRA FLATOW: Yeah, I’d ask if I could take it home with me. You know, this is working so well. I’d like–

SOPHIE BUSHWICK: I would love to use it if I’m trying to look behind me while I’m sitting in the car. Instead of using the rear facing camera, you can just turn your head a little bit and see behind you.

IRA FLATOW: Hey, I think you’ve got a product here, Sophie. Instead of your backup camera, why do I need it, right? I’ve got it on my head.

SOPHIE BUSHWICK: Yeah you just need to drive around everywhere in a VR headset. What could go wrong?

IRA FLATOW: What– exactly. Always great to have you, Sophie. Thanks for taking time to be with us today, and have a great holiday weekend.

SOPHIE BUSHWICK: You too. Thanks.

IRA FLATOW: Sophie Bushwick, senior news editor at New Scientist.

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