Profiling Molecular and Connection Specification of the Mouse Trigeminal Ganglia Nuclei

The trigeminal ganglia (TG) and associated brainstem nuclei constitute a sensory circuit essential for facial sensation in mice. Primary sensory neurons in the TG innervate the face, oral cavity, and nasal regions, projecting to brainstem trigeminal nuclei (TGN) before relaying to higher brain regions including the ventral posterior medial nucleus of thalamus (VPM), reticular formation, cerebellum, and superior colliculus. This circuit processes facial sensory information for behaviors like whisking, feeding, and protective reflexes. While these major pathways are well-documented, the cellular composition and organization of the TGN remain poorly understood. Here, we performed comprehensive molecular profiling and circuit tracing to characterize TGN neuronal diversity and identified novel pathways suggesting potential feedback regulation of the TGN.