We made our first rodent automobile out of a plastic cereal container. After trial and error, my colleagues and I discovered that rats could learn to drive forward by grasping a small wire that acted like an accelerator pedal. Soon they were steering with surprising precision to achieve a treat within the Froot Loop.
As expected, rats kept in a designed environment—complete with toys, space, and companions—learned to drive faster than rats in standard cages. This finding supported the concept Complex environments improve neuroplasticity: the power of the brain to alter throughout life in response to environmental demands.
After we published our research, the story of the drifting rats followed went viral within the media. The project continues in my lab with latest, improved rat-powered vehicles, or ROVs, designed by a robotics professor John McManus and his students. These upgraded electric ROVs—with rat-proof wiring, indestructible tires, and ergonomic control levers—resemble a rodent version of Tesla's Cybertruck.
As a neuroscientist who’s committed to it Since we house and test laboratory animals in natural habitats, I discovered it amusing to see how far we deviated from my laboratory practices on this project. Rats typically prefer dirt, sticks, and rocks over plastic items. Now we allow them to drive cars.
But humans didn't evolve to drive cars either. Although our ancient ancestors didn’t have cars, They had flexible brains This allowed them to accumulate latest skills – fire, language, stone tools and agriculture. And a while after the invention of the wheel, people made cars.
Although cars made for rats are removed from the whole lot they encounter within the wild, we thought driving a automobile presented an interesting method to study how rodents acquire latest skills. Unexpectedly, we found that the rats had strong motivation for his or her driving training, often jumping into the automobile and revving the “lever engine” before their vehicle hit the road. Why was that so?
The latest goal of joy
Concepts from introductory psychology textbooks got a brand new, practical dimension in our rodent driving laboratory. Building on fundamental learning approaches comparable to: operant conditioningwhich reinforces goal-directed behavior through strategic incentives, we trained the rats step-by-step of their driving programs.
First, they learned basic movements, comparable to stepping into the automobile and operating a lever. But with practice, these easy actions evolved into more complex behaviors, comparable to steering the automobile to a particular destination.
The rats also taught me something profound one morning through the pandemic.
It was the summer of 2020, a time marked by emotional isolation for nearly everyone on the planet, even lab rats. As I entered the lab, I noticed something unusual: the three driver-trained rats eagerly ran to the side of the cage and jumped up, like my dog does when asked if he desires to go for a walk.
Had the rats all the time been doing this and I just hadn't noticed? Did they only wish to experience a Froot loop or were they expecting the ride itself? Whatever the case, they gave the impression to be feeling something positive – perhaps excitement and anticipation.
Behaviors related to positive experiences are related to joy in humans, but what about rats? Did I see something like joy in a rat? Maybe so, provided that neuroscientific research increasingly suggests so Joy and positive emotions play a critical role within the health of each human and non-human animals.
In doing so, my team and I even have shifted the main focus from topics comparable to the impact of chronic stress on the brain to the query of how positive events – and the anticipation of those events – influence neural function.
Kelly Lambert, CC BY-ND
Collaboration with a postdoctoral researcher Kitty HartvigsenI designed a brand new protocol that uses waiting times to extend anticipation of a positive event. Incorporating Pavlovian conditioning, rats had to attend quarter-hour after a Lego brick was placed of their cage before receiving a Froot Loop. They also had to attend of their transport cage for a couple of minutes before entering Rat Park, their play area. We also added challenges like having them shell sunflower seeds before eating them.
That became ours Wait for it Research program. We called this latest series of studies UPERs—unpredictable positive experiential responses—during which rats were trained to attend for rewards. In contrast, control rats received their rewards immediately. After a couple of month of coaching, we subject the rats to numerous tests to find out how waiting for positive experiences affects their learning and behavior. We are currently peering into their brains to map the neural footprint of prolonged positive experiences.
Preliminary results suggest that rats forced to attend for his or her rewards show signs of switching from a pessimistic cognitive style to an optimistic one in a test measuring rodent optimism. They performed higher on cognitive tasks and were bolder of their problem-solving strategies. We linked this program to our laboratory's broader interest in Behavioral medicationsa term I coined to suggest that experiences can change brain chemistry in an identical method to drugs.
This research provides further evidence of how anticipation can reinforce behavior. Previous work with laboratory rats has shown that rats that press a bar to receive cocaine – a stimulant that increases dopamine activation – already feeling a dopamine rush as they expect a dose of cocaine.
The story of rat tails
It wasn't just the results of anticipation on rat behavior that caught our attention. One day, a student noticed something strange: One of the rats within the group, trained to expect positive experiences, had an upward-pointing tail with a curve at the top that resembled the handle of an old-fashioned umbrella.
I had never seen this in my many years of working with rats. When we reviewed the video footage, we found that the rats that were trained to anticipate positive experiences were more prone to hold their tails up than untrained rats. But what exactly did that mean?
Kelly Lambert, CC BY-SA
Curious, I posted an image of the behavior on social media. Other neuroscientists identified this as a gentler type of what is named Straub tailtypically observed in rats given the opioid morphine. This S-shaped curl is just too linked to dopamine. When dopamine is blocked, Straub's tail behavior decreases.
Natural types of opiates and dopamine — key players in brain pathways that reduce pain and increase rewards — look like telltale components of the raised ends in our anticipation training program. Observing tail posture in rats adds a brand new level to our understanding of rat emotional expression and reminds us that emotions are expressed throughout the body.
While we will't directly ask rats whether or not they enjoy driving, we have now developed a behavioral test to evaluate their motivation to drive. Instead of just giving the rats the chance to drive to the Froot Loop Tree this time, they may also walk – or on this case, paw – a shorter distance.
Surprisingly, two of the three rats selected the less efficient route of turning away from the reward and running to the automobile to drive to their Froot Loop destination. This response suggests that the rats enjoy each the journey and the worthwhile destination.
Rat lessons to benefit from the journey
We're not the one team studying positive emotions in animals.
Neuroscientist Jaak Banksepp famous tickled ratsshow their Ability to enjoy.
Research has also shown that a low-stress environment is desirable for rats retune their brain's reward circuitscomparable to the nucleus accumbens. When animals are kept of their preferred environment, the world of the nucleus accumbens that responds to appetitive experiences expands. Conversely, when rats are kept in stressful environments, the anxiety-provoking zones of their nucleus accumbens expand. It's as if the brain is a piano that may tune the environment.
The neuroscientist Curt Richter also advocated for this Rats which have hope. In a study that wouldn't be allowed today, rats swam in glass cylinders full of water and eventually drowned from exhaustion in the event that they weren't rescued. Laboratory rats, often handled by humans, swam for hours to days. Wild rats gave up after just a couple of minutes. However, when the wild rats were rescued for less than a short while, their survival time increased dramatically, sometimes by days. It seemed that the rescue gave the rats hope and spurred them on.
The Driving Rats project has opened latest and unexpected doors in my behavioral neuroscience research lab. While it’s important to look at negative emotions comparable to fear and stress, positive experiences also shape the brain in significant ways.
As animals—human or otherwise—address the unpredictability of life, anticipating positive experiences helps foster persistence to proceed looking for life's rewards. In a world of fast gratification, these rats offer insights into the neural principles that govern on a regular basis behavior. Instead of pushing buttons for fast rewards, they remind us that planning, forethought and having fun with the ride may be the important thing to a healthy brain. There's a lesson here, my lab rats taught me well.
image credit : theconversation.com