World / Science & Health

Driving tiny cars soothes rats, pointing way toward nondrug therapy for humans


Scientists have trained rats to drive tiny cars and found that learning the task lowered their stress levels.

Their study not only demonstrates how sophisticated rats’ brains are, but could one day help in developing new nonpharmaceutical forms of treatment for mental illness, said senior author Kelly Lambert of the University of Richmond in Virginia on Wednesday.

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 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’s compartment with an aluminum plate on the bottom.

Copper wire was threaded horizontally across the cab to form three bars: left, center and right.

When a rat placed itself on the aluminum floor and touched the wire, the circuit was completed and the car moved in the direction selected.

Seventeen rats were trained over several months to drive around an arena 150 centimeters by 60 centimeters.

Writing in the journal Behavioural Brain Research, the researchers said the animals could indeed be taught to drive forward as well as steer in more complex navigational patterns.

As she had suspected, Lambert found that the animals kept in stimuli-rich 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’ feces was collected after their trials to test for the stress hormone corticosterone as well as for dehydroepiandrosterone, which counters stress.

All rats that underwent training had higher levels of dehydroepiandrosterone, indicating a more relaxed state, which could be linked to the satisfaction of gaining mastery over a new skill — boosting what is referred to as “self-efficacy” or “agency” in humans.

What is more, rats that drove themselves showed higher levels of dehydroepiandrosterone as compared to those that 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 Lambert was the potential for new avenues of treatment the work opened up for people suffering from mental health conditions.

“There’s no cure for schizophrenia or depression,” 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 behavior can change our neurochemistry.”

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