title: Trigeminal ganglion innervates the auditory brainstem.
abstract: A neural connection between the trigeminal ganglion and the auditory brainstem was investigated by using retrograde and anterograde tract tracing methods: iontophoretic injections of biocytin or biotinylated dextran-amine (BDA) were made into the guinea pig trigeminal ganglion, and anterograde labeling was examined in the cochlear nucleus and superior olivary complex. Terminal labeling after biocytin and BDA injections into the ganglion was found to be most dense in the marginal cell area and secondarily in the magnocellular area of the ventral cochlear nucleus (VCN). Anterograde and retrograde labeling was also seen in the shell regions of the lateral superior olivary complex and in periolivary regions. The labeling was seen in the neuropil, on neuronal somata, and in regions surrounding blood vessels. Retrograde labeling was investigated using either wheatgerm agglutinin-horseradish peroxidase (WGA-HRP), BDA, or a fluorescent tracer, iontophoretically injected into the VCN. Cells filled by retrograde labeling were found in the ophthalmic and mandibular divisions of the trigeminal ganglion. We have previously shown that these divisions project to the cochlea and middle ear, respectively. This study provides the first evidence that the trigeminal ganglion innervates the cochlear nucleus and superior olivary complex. This projection from a predominantly somatosensory ganglion may be related to integration mechanisms involving the auditory end organ and its central targets.
authors.affiliation: Kresge Hearing Research Institute, University of Michigan, Ann Arbor, Michigan 48109-0506, USA. Sushore@umich.edu
authors.forename: S E
authors.initials: SE
authors.lastname: Shore
authors.forename: Z
authors.initials: Z
authors.lastname: Vass
authors.forename: N L
authors.initials: NL
authors.lastname: Wys
authors.forename: R A
authors.initials: RA
authors.lastname: Altschuler
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D001931:Brain Mapping; D001933:Brain Stem / Q000502:physiology*; D017626:Cochlear Nucleus / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D009847:Olivary Nucleus / Q000502:physiology; D011247:Pregnancy; D012668:Trigeminal Ganglion / Q000502:physiology*; D014278:Trigeminal Nuclei / Q000502:physiology