U-M Finds Neural Circuit Driving Rodent Gnawing

Researchers discover a touch-guided neural circuit that regulates motivated gnawing to maintain dental alignment in rodents, which could help lead to more effective treatments for oral health issues.

Published on Mar. 11, 2026

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Researchers at the University of Michigan have discovered that the constant gnawing of rodents isn't just a reflex or a consequence of a tough diet. It also triggers a release of dopamine in the brain, which acts as a biochemical reward or incentive, through a newly identified neural circuit. This connection could help explain why dogs chew bones and why people bite their nails, and it could lead to more effective interventions for conditions like bruxism and malocclusion in humans.

Why it matters

The finding reveals a previously hidden motivation for gnawing in mammals, which could help lead to more effective treatments for oral health issues. Identifying this circuit provides a concrete biological explanation for why these repetitive behaviors are sustained over time, which could have implications for understanding and treating conditions like teeth grinding and jaw misalignment in humans.

The details

The researchers found that touch-sensitive neurons in the tissue around teeth send signals to a junction that connects to two distinct paths - one to motor neurons that help move the jaw and position the incisors, and another that extends into the midbrain where it activates a dopamine center, giving rise to the motivational component of the behavior. Blocking the motivation pathway still allows the sensory-motor pathway to help maintain teeth, but without the motivation, it's not as efficient.

  • The study was published in the journal Neuron on March 11, 2026.

The players

Bo Duan

Associate professor in the U-M College of Literature, Science, and the Arts Department of Molecular, Cellular and Developmental Biology, and the lead author of the study.

Joshua Emrick

Assistant professor at the U-M School of Dentistry and a co-author of the study, who is a dentist and sensory neuroscientist.

University of Michigan

The institution where the research was conducted.

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What they’re saying

“In the old point of view, everyone sort of believed that gnawing was a very passive behavior driven by mechanical considerations. What we're learning is that this is indeed a motivated behavior. There is a defined neural circuit that connects sensory input from the teeth to dopamine neurons in the midbrain.”

— Bo Duan, Associate professor (Mirage News)

“If you have a malfunction in the system at a higher level, it ultimately can be very destructive for our oral tissues and, honestly, we don't have targeted treatments for the underlying issue. We need a fundamental understanding of how and where these behaviors are being driven in the brain.”

— Joshua Emrick, Assistant professor (Mirage News)

What’s next

The team is now exploring whether similar sensory-reward pathways regulate other behaviors beyond gnawing, as they believe this may represent a more general principle. Understanding how these circuits are organized could eventually help target them when the behavior becomes maladaptive.

The takeaway

This study provides a concrete biological explanation for why repetitive oral behaviors like gnawing, teeth grinding, and nail-biting are sustained over time, and it could lead to more effective treatments for conditions like malocclusion and bruxism by revealing the connection between sensations in the mouth and dopamine releases in the brain.