Summary: Researchers have trained rats to drive “rodent operated vehicles.” The rats were able to navigate the vehicle in unique ways and utilized novel steering patterns to find rewards. The findings reveal rats’ brains are more flexible than previously thought. Exploring how rats perform complex tasks may shed light on a range of mental health conditions and cognitive impairments.
Source: University of Richmond
Professor of Behavioral Neuroscience Kelly Lambert and her research colleagues have just published this research in the Behavioural Brain Research journal article “Enriched Environment Exposure Accelerates Rodent Driving Skills.”
This research explores how performing complex tasks, like driving, may further inform the science community about treatment for mental health conditions such as anxiety and depression.
“We already knew that rodents could recognize objects, press bars, and find their way around mazes, but we wondered if rats could learn the more complex task of operating a moving vehicle,” Lambert said.
The research team built a tiny car for the rats out of a clear plastic food container on wheels, with an aluminum floor and three copper bars functioning as a steering wheel. A total of 17 rats were trained to drive in rectangular arenas. Rats who passed their driver’s education were rewarded with Froot Loops.
“They learned to navigate the car in unique ways and engaged in steering patterns they had never used to eventually arrive at the reward,” says Lambert.
Results from this study include the following:
Rats’ brains are more flexible than previously thought. This finding could be used to understand how learning new skills may build a sense of control over the animal’s environment that may ultimately reduce stress. Because so many psychiatric illnesses such as depression and various anxiety disorders are exacerbated by stress, anything that relieves stress may provide a buffer against the onset of mental illness.
In the published study, rats that participated in the driving training had healthier stress hormone profiles than they had prior to their training. The researchers assessed hormones by measuring levels of two hormones: corticosterone, a marker of stress, and dehydroepiandrosterone (DHEA), which counteracts stress. The ratio of DHEA to corticosterone in the rats’ poop increased over the course of their driving training. In a previous study presented at the International Behavioral Neuroscience Society last summer, Lambert’s team compared driving rats to passenger (Uber) rats. They drove the Uber rats around in a remote control car for the same distances as the yoked driver rats so that the experiences were matched other than having control of the “wheel.” In this study the driving rats had higher DHEA levels (healthy hormone change) than the Uber rats. “We concluded that the rats that actually learned to drive had a greater sense of control over their environment that was accompanied by increased DHEA — something like a rodent version of what we refer to as self-efficacy or agency in humans,” Lambert said.
Rats housed in a complex, enriched environment (i.e., environment with interesting objects to interact with) learned the driving task, but rats housed in standard laboratory cages had problems learning the task (i.e., they failed their driving test).” That means the complex living environment led to more behavioral flexibility and neuroplasticity,” Lambert said. “This reminds us that our brains are constantly changing in response to our environments — and that we’re accountable for maintaining our brains moment-to-moment.”
The research team included fellow psychology professor Laura Knouse, and Apple data scientist Beth Crawford, a former psychology faculty member at UR. Alum Olivia Harding, now a research lab assistant at UR, is also assisting with this research, which she began working on as an undergraduate. Additionally, several undergraduate students were co-authors on the published manuscript and continue to work on the research program.
As for next steps, the team is now planning follow-up experiments to understand how the brain changes to accommodate the acquired driving skills — that is, the neuroplasticity that accompanies the driving training. They will also continue to explore how task mastery — e.g., driving or mastering other complex tasks — modify the stress and coping response to new challenges.
Although rarely used, long-term behavioral training protocols provide opportunities to shape complex skills in rodent laboratory investigations that incorporate cognitive, motor, visuospatial and temporal functions to achieve desired goals. In the current study, following preliminary research establishing that rats could be taught to drive a rodent operated vehicle (ROV) in a forward direction, as well as steer in more complex navigational patterns, male rats housed in an enriched environment were exposed to the rodent driving regime. Compared to standard-housed rats, enriched-housed rats demonstrated more robust learning in driving performance and their interest in the ROV persisted through extinction trials. Dehydroepiandrosterone/corticosterone (DHEA/CORT) metabolite ratios in fecal samples increased in accordance with training in all animals, suggesting that driving training, regardless of housing group, enhanced markers of emotional resilience. These results confirm the importance of enriched environments in preparing animals to engage in complex behavioral tasks. Further, behavioral models that include trained motor skills enable researchers to assess subtle alterations in motivation and behavioral response patterns that are relevant for translational research related to neurodegenerative disease and psychiatric illness.