These scientists taught rats to drive tiny cars. Turns out, it's good for them
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REGINA BARBER: You're listening to Short Wave from NPR. Hey, Short Wavers, Regina Barber here. And today, our story starts with a rat scientist.
KELLY LAMBERT: You know, I know we're not a big rat, and they're not little humans. But at a basic level, they have mostly all the same brain areas, neurochemicals, like dopamine and serotonin, and plasticity kind of fertilizers that we look at. All of that is in a rat brain.
BARBER: That's Kelly Lambert. She's a professor of behavioral neuroscience at the University of Richmond. And a while ago, this colleague of hers, a cognitive scientist who's into robotics and design, reached out with kind of a weird question.
LAMBERT: She sent an email one night and said, Kelly, can you teach a rat to drive a car? And I consider myself a serious-minded neuroscientist, so my initial response was, why would I want to do that?
BARBER: But then she reconsidered.
LAMBERT: Once you start thinking about teaching a rat to drive a car, you can't not think about it. You can't stop thinking about it.
BARBER: Fast-forward to a couple of years later. Guess what this is?
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BARBER: If you guessed that's the sound of a rat driving a tiny car, you're right. Kelly's rats are in a lab at the University of Richmond, zooming in these four-wheeled little plastic boxes around this big arena.
LAMBERT: Almost like a playpen around the entire room and then some kind of flooring that we put that we roll out that's a flat surface. And it's black and white checked, so it kind of has this raceway kind of idea. And we start the car on one end. And at the other end is what we call the Froot Loop tree. And we have little straws with Froot Loops attached via marshmallows. We do give them healthy food. They just have these treats.
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BARBER: And in 2020, right at the peak of the COVID lockdown, watching these rats, Kelly had a breakthrough.
LAMBERT: We were all feeling isolated, low emotion. The students had been sent home. So I remember going in one day feeling that, ugh, low kind of feeling. And we had three rats that were our driver rats. And they ran up to the side of the cage, literally kind of jumping up and down like my dog, Brody, does when I say, want to go for a walk? And he's, you know, flipping around. And they were reaching out to me. Now, maybe they just associated me with a big Froot Loop, but it made me feel accepted, good, that they were excited for something.
BARBER: So that's what Kelly and her team are studying now, anticipation. They teach the rats how to drive these little cars in different situations and environments. And they study how these rats respond, how it changes their brains and their behavior.
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BARBER: So today on the show, we're learning from rats about anticipation, decision-making, and how to enjoy life. I'm Regina Barber, and you're listening to Short Wave, the science podcast from NPR.
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BARBER: Hey, Short Wavers, Regina Barber here. Before we get back to the show, can you give me a quick minute to talk to you about what makes Short Wave possible, aside from caffeine, a well-calibrated circadian rhythm, and a love of science, specifically, astronomy? Aside from all that, what really makes Short Wave possible is you. That's because we work for NPR, and NPR is public media, which means we exist not to make money, but to create a more informed public. Public media is kind of like a sidewalk or a public park. It's infrastructure that we all use. It's free. It's for everyone. That's why we work really hard to bring you stories about science that matter to you, no matter where you live or what community you belong to. We love doing that work. So this time of year, we are saying, thank you. Thank you for listening. Thank you for your support. And wouldn't you know, it's Giving Tuesday. That means it's a perfect time to keep Short Wave going. Sign up for sponsor-free episodes and similar perks across more than 25 podcasts with NPR+ today. Join us at plus.npr.org. plus.npr.org. That link is in our episode notes. And if you don't want podcast benefits, no one can stop you from simply just going to donate.npr.org. Your gifts are tax-deductible either way you choose to give. OK, thank you for listening, and back to the show. OK, Kelly, describe this setup. So, like, what do the carts look like that the rats are driving? And how do they do it?
LAMBERT: Right now, we're in our third version of our rat car, so we're in rat car 3 that we call rodent-operated vehicles.
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LAMBERT: They're a little smaller than a shoe box. And they have the tires, and they have a steering mechanism that we had to figure out. And we use kind of old-fashioned operant behavioral conditioning with a Froot Loop as the incentive-- that's the currency of my lab-- to shape them behaviorally to enter the car, to stay in the car, to press the lever and keep that lever pressed to activate and to drive the car to the Froot Loop tree, which is their destination.
BARBER: [LAUGHS] OK, that seems like a lot of work, but you're saying these rats, they like this. They like driving. Like, how do you know that? Is it from their brains? Is it from their behavior? Or is it, like, both?
LAMBERT: That's a really interesting question, and probably the most popular question, frequent question, that people have asked me. Do they like it? And I can't give them a Qualtrics survey or something like that. So I can look at their behavior. When we bring them into the lab and to their driving arena, we transport them from their transport cage into the car, they jump in automatically. So that suggests that they're at least approaching something, and that's usually related to something they like. And as we're putting them into the driving arena, before they even hit the rat road, they start activating the lever. And it sounds like they're revving up the engine.
BARBER: Yeah, I watched the videos. I saw them, like, revving it up. It really seemed like they were, like, so ready to go.
LAMBERT: Yeah. So approach is one way that a behavioral scientist, like myself, could understand that. I wanted to explore it a little bit more definitively with that small group. So they had only been able to access the Froot Loop tree in their car in the past training. But I asked my students to let them get into the arena without the car and just see that they could clearly just walk down to that Froot Loop tree. So the test, in this preliminary study, was to put the car at one end of the arena, as we always had done. The Froot Loop tree was in the other end, and we put the rat outside of the car just in the middle of the arena. So the most efficient way to get to the Froot Loop would be to simply walk or run to the Froot Loop tree, eat all the Froot Loops you want. One rat consistently did this. We have individual differences with rats, and I love that.
BARBER: That's the smart one.
LAMBERT: Yeah. Two of the rats, they hesitated. They turned around, saw the car, and not walked, but kind of ran to the car, jumped in, and drove to the Froot Loop tree. Not once, not twice, but day after day, they are preferring to drive to the Froot Loop tree as opposed to walk to it. That driving increased the anticipation.
BARBER: OK, I'm just going to, like, pause you right there, because I want to talk about this, like, anticipation, because I know that there are these other studies out there indicating that there's, like, natural dopamine being released in these rats as they're, like, anticipating reward. And it seems like you're, like, building on these studies. Can you explain how, like, driving fits into all that?
LAMBERT: Yeah. I developed, with my colleagues, a whole new protocol looking at-- I call it unpredictable positive experience responses. So at random times during the day, we're giving them these positive experiences. So they never know when it's coming. And then they have to wait for it. So I'm really trying to ramp up anticipation for something good. And we are starting to write up our initial data. But it's looking like we are indeed sculpting their brains differently, their behaviors, their vocalizations, whether or not they're happy or sad calls. And so if we think-- if I think about my life, you know, if we're looking forward to a vacation with a family, and you're thinking and planning, it's rare that the actual event meets all those expectations. So maybe the anticipation is even more rewarding than the actual event sometimes. But if we deprive ourselves of all that anticipation, we're really depriving our brains of a lot of feel-good chemicals and such. So the rats, maybe prolonging the feel-good time, [LAUGHS] the time that they're enjoying driving or anticipating that Froot Loop.
BARBER: OK, so you mentioned that there are, like, physical, like, behavioral cues that these rats are-- they are experiencing this dopamine. Can you tell me a little bit more?
LAMBERT: Yeah. Again, it's exploratory, but just kind of blew my mind. So we were doing another test with these-- we call them upper-trained or positive anticipation-trained rats, where they were in an arena. And a student said, Dr. Lambert, why does the rat have its tail sticking straight up? And it was like an umbrella, you know, kind of a hook. And sure enough, the upper-trained or anticipatory-trained animals had it sticking up more. And I didn't know what this meant. So I put a picture on social media. Said, has anyone seen this? Because I just hadn't. And a few people said, oh, yes. If you inject morphine into a mouse or a rodent, their tail goes up. And I thought, have we--
BARBER: Wow.
LAMBERT: Have we changed these opiates in these animals through behavioral training? So dopamine for pleasure and opiates for well-being, that's a pretty good cocktail from behavioral training. And I've introduced this word, behaviorceuticals, that we can change our-- so it was maybe the perfect behaviorceutical, but we're still exploring. It's just great to watch the animals, and they give you clues about what to look at next.
BARBER: That's amazing. And I really like this, like, term that you've coined, this, like, behaviorceuticals, this idea that behaviors can alter your brain chemistry, what you're seeing, like, similar to pharmaceuticals. How does this work with driving rats? Like, add to that line of research.
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LAMBERT: Yeah, so we found that just going through the training itself, regardless if they learned to drive or not, that changed at least the hormone profiles.
BARBER: Aw. So it doesn't even matter if they're a good driver or not? They just--
LAMBERT: Yes, it's the process, the journey, not the destination.
BARBER: Yeah, really.
LAMBERT: There's research to suggest that stress can impair neuroplasticity, or at least, they help veer kind of versions of plasticity. So if this training is helping them regulate their emotions and have lower levels of stress hormones, that's going to have, probably, a positive impact on the brain. So if we know more about how we can intentionally and systematically change our behavior to change our brains in healthy ways-- Most of the research is related to changing neurochemistry through pharmaceuticals, but I wanted there to be more attention on the behavior. We know that cognitive behavioral therapy is very effective with humans, but we don't have good preclinical models. We're not sure exactly what that's doing. So I'm trying to replicate some of that with the animals so that we know more about what it's doing, and that may elevate the respect for behavioral interventions.
BARBER: Right. Yeah. And neuroplasticity, as you're saying, is, like, the brain's ability to, like, change and learn, right? And so to sum up, like, training new skills helps these rats, like, regulate emotions, which lowers stress, which makes their neuroplasticity stronger, right? Like, it's a cycle.
LAMBERT: You got it. Yeah. And this has lots of lessons. But now, I'm excited about what we can learn from other animals. Rats don't represent all mammals or all animals or all brains. More research is done on mice now. It's convenient. We know a lot about how to house them and do research. But let's look at wild animals. Let's look at different-- I love raccoons. They're out there working the environment, and they're so smart.
BARBER: They're so smart.
LAMBERT: We don't keep them in the lab, but they look like primate brains. There's a reason we can't invent or design a garbage can to keep them out. So I think there are a lot of species out there that hold a lot of secrets that may unlock some mysteries about some of the psychiatric and neurological illnesses that we face. So we need to diversify our research portfolios.
BARBER: Wow. Aside from, like, what is scientifically proven and, like, how similar rats' brains are to human brains, what has this work done for you, like, personally? Has it changed how you look at life, how you look at anticipation and about delayed gratification and working for things?
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LAMBERT: Yes, on so many levels. A lot of research is focused on protecting children from trauma, and that's so important when we have adverse childhood experiences. We want to minimize the stress, the trauma. Little challenges are great, but horrible things that happen, that's so impactful for the brain, and we need to keep that up. But what about if a child has something to look forward to? While a pediatrician is asking about stressors in a child's life, I'd love to start thinking about the impact of asking, what are you looking forward to? Anticipation kicks in a lot of really healthy brain responses related to curiosity and planning and all that dopaminergic activity. So we need to balance the scale. And we've been a little one-sided focusing on avoiding the negative, but we need to add to that to extend that anticipation, like we're doing with the rats. Or maybe they never know when something good is going to happen, or they know that they can wait, and it's coming. That's also, I think, very healthy for brains. We're exploring it.
BARBER: I love it. I'm going to take this and be like, you know, you can actually think that random good things are going to happen, too, not just bad things.
LAMBERT: Yeah. That's not the way our culture is. It's just, what is the next bad thing that's going to happen?
BARBER: Right. But now, I'm going to be like your rats. I'm going to be like, one day, there'll be a Froot Loop tree.
LAMBERT: [LAUGHS] Yes. Yes.
BARBER: Well, thank you so much for sharing your work with us.
LAMBERT: You're welcome. I love sharing our brain stories with anyone interested in hearing them.
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BARBER: This episode was produced by Hannah Chinn. It was edited by showrunner Rebecca Ramirez. Tyler Jones checked the facts. James Keeley was the audio engineer. Beth Donovan is our senior director, and Collin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Short Wave from NPR.
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