Neural Circuit Fuels Rodents' Gnawing Instinct

Researchers discover dopamine reward system behind rodents' constant need to chew.

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 may provide insights into conditions like bruxism and malocclusion.

Why it matters

The study's findings provide a concrete biological explanation for why repetitive oral behaviors are sustained over time in both animals and humans. Understanding this neural circuit could lead to more effective interventions for conditions affected by dopamine regulation, such as teeth grinding and misaligned bites.

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 another that extends into the midbrain to activate a dopamine center, giving rise to the motivational component of the behavior. Blocking the motivation pathway still allows for mechanical maintenance of the teeth, but without the dopamine reward, the behavior becomes less 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 (Neuron)

“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 (Neuron)

What’s next

The research team is now exploring whether similar sensory-reward pathways regulate other behaviors beyond gnawing, as they believe this may represent a more general principle that could help target maladaptive behaviors.

The takeaway

This study provides a concrete biological explanation for why repetitive oral behaviors are sustained over time in both animals and humans, which could lead to new treatments for conditions like teeth grinding and misaligned bites that are linked to dopamine regulation in the brain.