Papers of the Week

The trigeminal ganglion (TG) comprises primary sensory neurons responsible for orofacial sensations, subsequently projecting to the trigeminal nuclei in the brainstem. However, the circuit basis of nasal mechanosensation is not well characterized. Here we elucidate the anatomical organization of both peripheral and central projections of the TG. We found that the non-peptidergic nociceptor, MrgprD neurons in the TG densely innervate the nasal mucosa, whereas the LTMRs subtypes rarely innervate the nasal mucosa. We also identified the central projection pattern of the mechanosensory neurons in TG. TrkC neurons project to dorsal part of the brainstem trigeminal complex and the solitary nucleus. TrkB neurons project to the Pr5VL, Sp5O, Sp5I and Sp5C. TH neurons project to ventrolateral Sp5I, the outer edge of Sp5C and the caudal part of solitary nucleus. Additionally, the MrgprD neurons only densely project to outer edge of Sp5C. In addition, we further determined the ascending pathway of the TG neurons. Taken together, our study demonstrates the peripheral and central projection pattern of mechanosensory neurons in the TG, which provides a basis for the future functional studies.