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bioRxiv · 10.64898/2026.10.14.759217

Brainstem premotor circuits transform dental sensory input into coordinated jaw opening

Liu, L.-Y.·Lee, H.·Wagner, N.·Hunter, K.·Lee, E.·Constantinescu, B. S. C.·Dakhilalla, L.·Chang, A.·Duan, B.·Emrick, J.
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Abstract

Protective actions require the rapid transformation of damage into coordinated activity of motor pools, yet the brainstem circuits implementing this operation remain poorly defined. Here, we use the tooth-trigeminal system to identify molecularly specified pathways linking intradental sensory input to opposing jaw motor pools. Optogenetic activation of tooth-associated sensory afferents evoked rapid, stimulus-locked jaw-opening. Intradental afferents formed functional monosynaptic connections with Pdyn+ neurons in the 5Sol transition zone and Calb2+ neurons in the 5Tr transition zone, identifying these regions as sensory-recipient premotor interfaces. Predominantly excitatory Pdyn+ 5Sol neurons provided monosynaptic input to anterior digastric motor neurons, whereas predominantly inhibitory Calb2+ 5Tr neurons provided bilateral monosynaptic input to masseter motor neurons. Activation of Pdyn+ 5Sol neurons was sufficient to evoke jaw opening. Together, these findings define complementary brainstem pathways positioned to couple jaw-opening drive with inhibition of antagonistic jaw-closing output, revealing a withdrawal-like sensorimotor computation adapted to cranial biomechanics.

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Liu, L.-Y., Lee, H., Wagner, N., Hunter, K., Lee, E., Constantinescu, B. S. C., Dakhilalla, L., Chang, A., Duan, B., Emrick, J.. 2026-10-16. Brainstem premotor circuits transform dental sensory input into coordinated jaw opening. https://doi.org/10.64898/2026.10.14.759217

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