title: Projections of the sensory trigeminal nucleus in a percomorph teleost, tilapia (Oreochromis niloticus).
abstract: The sensory trigeminal nucleus of teleosts is the rostralmost nucleus among the trigeminal sensory nuclear group in the rhombencephalon. The sensory trigeminal nucleus is known to receive the somatosensory afferents of the ophthalmic, maxillar, and mandibular nerves. However, the central connections of the sensory trigeminal nucleus remain unclear. Efferents of the sensory trigeminal nucleus were examined by means of tract-tracing methods, in a percomorph teleost, tilapia. After tracer injections to the sensory trigeminal nucleus, labeled terminals were seen bilaterally in the ventromedial thalamic nucleus, periventricular pretectal nucleus, medial part of preglomerular nucleus, stratum album centrale of the optic tectum, ventrolateral nucleus of the semicircular torus, lateral valvular nucleus, prethalamic nucleus, tegmentoterminal nucleus, and superior and inferior reticular formation, with preference for the contralateral side. Labeled terminals were also found bilaterally in the oculomotor nucleus, trochlear nucleus, trigeminal motor nucleus, facial motor nucleus, facial lobe, descending trigeminal nucleus, medial funicular nucleus, and contralateral sensory trigeminal nucleus and inferior olive. Labeled terminals in the oculomotor nucleus and trochlear nucleus showed similar densities on both sides of the brain. However, labelings in the trigeminal motor nucleus, facial motor nucleus, facial lobe, descending trigeminal nucleus, and medial funicular nucleus showed a clear ipsilateral dominance. Reciprocal tracer injection experiments to the ventromedial thalamic nucleus, optic tectum, and semicircular torus resulted in labeled cell bodies in the sensory trigeminal nucleus, with a few also in the descending trigeminal nucleus.
authors.affiliation: Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo 113-8602, Japan. xuehg@nms.ac.jp
authors.forename: Hao-Gang
authors.initials: HG
authors.lastname: Xue
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Chun-Ying
authors.initials: CY
authors.lastname: Yang
authors.forename: Gulnisa
authors.initials: G
authors.lastname: Kerem
authors.forename: Masami
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sawai
authors.forename: Hironobu
authors.initials: H
authors.lastname: Ito
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ozawa
mesh_terms: D000818:Animals; D023681:Cichlids / Q000033:anatomy & histology*; D004525:Efferent Pathways / Q000033:anatomy & histology*; D014278:Trigeminal Nuclei / Q000033:anatomy & histology*