WASHINGTON (AFP) - Sometimes life really can be a rat race.
Scientists have reported successfully training the rodents to drive tiny cars in exchange for tasty bits of Froot Loops cereal, and found that learning the task lowered their stress levels.
The study not only advances our understanding of how sophisticated rat brains are, but could also one day help in developing new non-pharmaceutical forms of treatment for mental illness, senior author Kelly Lambert of the University of Richmond told Agence France-Presse on Wednesday (Oct 23).
Dr Lambert said she had long been interested in neuroplasticity - how the brain changes in response to experience and challenges - and particularly wanted to explore how well rats that were housed in more natural settings ("enriched environments") performed against those kept in labs.
She and colleagues modified a robot car kit by adding a clear plastic food container to form a driver compartment with an aluminium plate placed on the bottom.
A copper wire was threaded horizontally across the cab's front to form three bars: left, centre and right.
When a rat placed itself on the aluminium floor and touched the wire, the circuit was complete and the car moved in the direction selected.
Seventeen rats were trained over several months to drive around an arena 150cm by 60cm made of Plexiglas, with the researchers establishing that the animals could indeed be taught to drive forward as well as steer in more complex navigational patterns.
As she had suspected, Dr Lambert found that the animals kept in so-called "enriched environments" performed far better than their lab rat counterparts, but "it was actually quite shocking to me that they were so much better", she said.
The rats' faeces were collected after their trials to test for the stress hormone corticosterone as well as dehydroepiandrosterone, which counters stress.
All rats that underwent training had higher levels dehydroepiandrosterone, indicating a more relaxed state, which could be linked to the satisfaction of gaining mastery over a new skill, referred to as "self-efficacy" or "agency" in humans.
What's more, rats that drove themselves showed higher levels of dehydroepiandrosterone as compared to those who were merely passengers when a human controlled the vehicle, meaning they were less stressed - something that will be familiar to nervous backseat drivers.
The biggest takeaway for Dr Lambert was the potential new avenues of treatment the work opened up for people suffering from mental health conditions.
"There's no cure for schizophrenia or depression. We're behind," she said. "And we need to catch up and I think we need to look at different animal models and different types of tasks and really respect that behaviour can change our neurochemistry."