Dancing rats reveal how the brain unconsciously perfects skillful movements

BALTIMORE — Perfecting complex movements, like playing an instrument or tying your shoes, all come down to one thing — practice, practice, practice. What makes this process interesting is the way our brains put their own little flair on these repetitive tasks. Now, a new study involving “dancing” rats is revealing just how the brain goes about learning and perfecting complex skills.

A team from the University of Maryland School of Medicine found that several brain regions work together to learn how to complete specific tasks flawlessly every time — like tying a shoe. Moreover, they found that each rat added their own personal “dance” to the exercise which helped them remember the repetitive acts.

“Besides following our basic curiosity to figure out how the brain works and how we learn movements, our work has many direct applications. Understanding the conditions under which healthy brains learn informs how people should train for highly skilled activities like certain sports,” says Steffen Wolff, PhD, a UMSOM assistant professor of pharmacology, in a university release. “More importantly, one day hopefully the insights gathered from this basic research program will help people with brain damage or diseases that affect movements.”

Breaking down the ‘choreography’ of the brain

The study authors say they’ve been training rats to examine how the brain learns and performs new skills. In the new experiment, the rats had to press a lever in a certain way in order to get a drink of water.

Just like baseball players develop their own superstitious movements before throwing a pitch or stepping into the batter’s box, the rats came up with their own little routine after successfully learning how to press the lever.

“During the learning process, they develop a little dance, and each rat comes up with their own choreography,” Dr. Wolff reports. “After they have perfected their technique, they continue to do whatever worked for them when learning: one animal will scratch the wall, another will tap their foot, and another sticks out their tongue, while simultaneously pressing the lever.”

In previous studies, the researchers damaged a rat’s motor cortex, the outermost layer of the brain. As a result, rats could not learn their dances tied to a certain movement. However, once the animals did learn a dance, they were capable of completing that certain skill even without using that brain region.

In another study, the team discovered another brain region vital for learning complex tasks — the basal ganglia. This region is deep inside the brain and scientists believe conditions like Parkinson’s disease damage it.

Their newest experiment put both these findings together to examine if the motor cortex teaches the basal ganglia how to replicate new skills. The team used viruses to shut down the connections between these brain areas. Results show that without the motor cortex teaching the basal ganglia, the rat could not develop a dance for their skills.

Back to basics when the brain stops functioning

The study also looked at the relationship between the basal ganglia and another brain region — the thalamus. When the team used viruses to disrupt the connection between these two regions, rats could still press the lever to receive water, but completely lost their unique dances.

Instead, the rats fell back into the initial habits of randomly swatting at the lever with their arms until they hit the switch correctly. Dr. Wolff believes these more simplistic motions are the work of more basic areas of the brain, like the brainstem.

“This work helps to reveal the logic of how individual brain regions work together to control skill learning and execution, a first step in our quest to help treat patients with motor movement disorders like Parkinson’s disease, and injuries from trauma or stroke to the motor-controlling parts of the brain,” concludes Dean E. Albert Reece, MD, PhD, MBA, Executive Vice President for Medical Affairs at UM Baltimore.

The study is published in the journal Science Advances.

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