I'm the neuroscientist who taught rats to drive cars. The joy of mice suggests how anticipating pleasure can enrich human life

We made our first rodent car from a plastic cereal container. Through trial and error, my colleagues and I discovered that rats can learn to move forward by squeezing a small wire that acts like a gas pedal. Eventually, they maneuvered with amazing precision and reached the Flute Loop treat.

As expected, rats raised in enriched environments with toys, space, and companions learned to drive faster than rats kept in standard cages. This finding supported the following ideas. Complex environments increase neuroplasticity: The brain's ability to change throughout life in response to environmental demands.

The story of kicking out a rat after publishing our research spread rapidly in the media. The project continues in my lab with the development of a new and improved rat-operated vehicle (ROV) designed by a robotics professor. John McManus And his students. These upgraded electric ROVs resemble rodent versions of Tesla's Cybertruck, with rat-proof wiring, unbreakable tires, and ergonomic driving levers.

as a neuroscientist who will defend I thought it would be interesting to see how much this project of raising and experimenting on laboratory animals in their natural habitat deviates from my laboratory practice. Rats usually prefer dirt, sticks, and stones to plastic objects. Well, we let them drive the car.

However, humans did not evolve to drive cars either. Our ancient ancestors did not have cars, they had flexible minds This allowed them to acquire new skills such as fire, language, stone tools, and agriculture. Shortly after the invention of the wheel, humans created cars.

Although cars built for rats are a far cry from what rats would encounter in the wild, we think driving is an interesting way to study how rodents acquire new skills. I did. Unexpectedly, the rats were found to have a strong motivation for driving training, often jumping into cars and revving the “lever engine” before the car hit the road. Why?

A new joy destination

A concept from an introductory psychology textbook takes on a new practical dimension in the rodent driving laboratory. Build on foundational learning approaches such as operant conditioningWe trained rats in a step-by-step driver education program to reinforce targeted behaviors through strategic incentives.

At first, we learned basic movements such as getting into a car and pushing levers. However, with practice, these simple actions evolved into more complex actions, such as steering a car toward a specific destination.

One morning during the pandemic, the mice taught me something profound.

It was the summer of 2020, a time of emotional isolation for just about everyone on the planet, including lab rats. When I entered the laboratory, I noticed something unusual. Three rats that had been trained to drive eagerly ran next to the cage and jumped up like my dog ​​does when asked if he wanted to go for a walk.

Do rats do this all the time and I just didn't notice? Were they simply eager for Flute Loop, or were they anticipating the drive itself? Either way, they seemed to be feeling some positive emotion, perhaps excitement and anticipation.

In humans, behaviors associated with positive experiences are associated with joy, but what about rats? Was I seeing something similar to joy in rats? Perhaps so, given that neuroscience research suggests that: joy and positive emotions It plays an important role in the health of humans and non-human animals.

This allowed my team and I to shift our focus from topics like how chronic stress affects the brain to how positive events and expectations about those events shape neural function. I did.

Collaboration with postdoctoral researchers kitty hartvigsenI designed a new protocol that uses a waiting period to build anticipation before a positive event. Bring Pavlovian conditioning After adding the Lego blocks to this mixture, the rats had to wait 15 minutes before receiving the Flute Loop. We also had to wait in a transport cage for several minutes before entering the rat park, which is a playground. They also added tasks such as peeling and feeding sunflower seeds.

this is now ours wait for it research program. We named this new line of research, in which rats were trained to wait for a reward, UPER (unpredictable positive experiential response). In contrast, control rats received the reward immediately. After about a month of training, the rats will be exposed to various tests to see how waiting for positive experiences affects their learning and behavior. We are now peering into their brains and mapping the neural footprint of extended positive experiences.

Preliminary results show that rats that have to wait for a reward show signs of shifting from a pessimistic to an optimistic cognitive style in a test designed to measure optimism in rodents. It suggests that. They performed better on cognitive tasks and were more bold in their problem-solving strategies. We connected this program with the broader interests of our laboratory. behavior cosmeticsa term I coined to suggest that experiences can change brain chemistry in the same way that medications can.

This study provides further support for how expectations reinforce behavior. Previous studies using laboratory rats have shown that they press the bar for cocaine, a stimulant that increases the activation of dopamine. Already experiencing a surge of dopamine Because they anticipate administering cocaine.

The story of the rat's tail

It wasn't just the effect of expectations on the rats' behavior that caught our attention. One day, the student noticed something strange. One rat in the group trained to expect positive experiences had a straight tail with a curved end, resembling the handle of an old-fashioned umbrella.

I've been working with rats for decades and had never seen anything like this. Reviewing the video footage, they found that rats trained to expect positive experiences were more likely to hold their tails high than untrained rats. But what exactly does this mean?

Curious, I posted a photo of the act on social media. Fellow neuroscientists have identified this as a milder form of the so-called condition. straub tailtypically seen in rats given the opioid morphine. This S-shaped curl too related to dopamine. When dopamine is blocked, Straub tail behavior subsides.

Natural opiates and dopamine are key players in the pain-reducing and reward-enhancing brain pathways and appear to be obvious components of tail elevation in our anticipatory training programs. Observing the rat's tail posture adds a new layer to our understanding of rat emotional expression and reminds us that emotions are expressed throughout the body.

Although we can't directly ask rats whether they like driving, we devised a behavioral test to assess their motivation to drive. This time, instead of just giving the mouse the option of driving to the Froot Loop Tree, he can also travel short distances on foot, or in this case, on his feet.

Surprisingly, two of the three rats chose the less efficient path of turning away from the reward and running to the car that would take them to their Froot Loop destination. This response suggests that the rats enjoy both the journey and the challenging destination.

Mouse lessons for enjoying your journey

We're not the only team studying positive emotions in animals.

neuroscientist jaak banksep famous tickled mousetheir ability to embrace joy.

Research also shows that a low stress environment is desirable for rats. Recalibrate the brain's reward circuitrynucleus accumbens, etc. When animals are kept in their preferred environment, the area of ​​the nucleus accumbens that responds to appetitive experiences expands. Alternatively, raising rats in stressful conditions expands the fear-producing region of the nucleus accumbens. It's as if the brain is a piano tuned by the environment.

Neuroscientist Kurt Richter also argued that: Mouse with hope. The study, which is no longer allowed, involved rats swimming in glass cylinders filled with water, until they eventually drowned from exhaustion unless rescued. Lab rats, frequently handled by humans, swam for hours to days. The wild mouse gave up after just a few minutes. However, when wild rats were rescued briefly, their survival was dramatically extended, sometimes by several days. It seems that being rescued gave the rats hope and courage.

The rat driving project opened an unexpected new door in my behavioral neuroscience laboratory. While it's important to study negative emotions such as fear and stress, positive experiences also greatly shape the brain.

As animals, human or otherwise, live unpredictable lives, the expectation of positive experiences can help encourage persistence in continuing to search for life's rewards. In a world of instant gratification, these rats provide insight into the neural principles that guide everyday behavior. It's a reminder that planning, anticipating, and enjoying the ride, rather than pressing a button and getting an instant reward, may be the key to brain health. That's a lesson for my lab rats. taught me well.