2026-03-10 ミシガン大学
Rodents, including squirrels, have to gnaw to keep their ever-growing incisors in order. New research from the University of Michigan reveals the neural circuitry that rewards this behavior, which could help develop better treatments for people with dental issues such as teeth grinding or jaw misalignment. Image credit: Connor Titsworth, Michigan Media Commons
＜関連情報＞
- https://news.umich.edu/gnaw-y-by-nature-u-m-researchers-discover-neural-circuit-that-rewards-gnawing-behavior-in-rodents/
- https://www.cell.com/neuron/abstract/S0896-6273(26)00046-2
触覚誘導神経回路が歯並びを維持するために動機づけられた噛みつきを制御する A touch-guided neural circuit regulates motivated gnawing to maintain dental alignment
Xin-Yu Su ∙ Elizabeth A. Ronan ∙ Sienna K. Perry ∙ … ∙ Dawen Cai ∙ Joshua J. Emrick ∙ Bo Duan
Neuron Published:March 10, 2026
DOI:https://doi.org/10.1016/j.neuron.2026.01.021
Highlights
- Sp5O SST⁺ neurons encode gnawing-evoked mechanosensation for incisor alignment
- Trigeminal Aβ-LTMRs relay gnawing-related tactile signals to Sp5O SST⁺ neurons
- Sp5O SST⁺ neurons synapse onto trigeminal motor neurons to control gnawing
- A Sp5O-LPB-VTA circuit underlies the motivational drive for gnawing
Summary
How hindbrain circuits integrate peripheral and central signals to regulate complex oral behaviors is poorly understood. In rodents, gnawing is essential for localized tooth wear to offset lifelong incisor growth. Whether this process relies on specific sensory input to guide localized tooth wear and is actively regulated by neural mechanisms remains unresolved. Here, we identify somatostatin-expressing neurons in the spinal trigeminal nucleus oralis as a central relay distributing tactile input to motor execution and motivational circuits. These neurons receive input from a genetically distinct population of S100b+ Aβ low-threshold mechanoreceptors that innervate the incisor periodontium and project to both jaw-closing motor neurons and, via the parabrachial nucleus, the ventral tegmental area. Disruption of this pathway abolished gnawing and resulted in severe malocclusion, while activation triggered dopamine release in the nucleus accumbens. Our findings redefine dental alignment as an active, touch-dependent, circuit-governed process and reframe malocclusion as a sensorimotor-motivational integration disorder.
