title: The somatotopic organization of trigeminal premotoneurons in the cat brainstem.
abstract: This study was performed to complement the results of prior intracellular recording and labeling studies by investigating the general distribution pattern of trigeminal premotoneurons in the cat brainstem using the retrograde tracing methods. The results of the present study reconfirmed the presence of premotoneurons in the trigeminal principal and oral nuclei following horseradish peroxidase injections into the jaw-opening (JO) or jaw-closing (JC) nucleus. Furthermore, we found that labeled cells from the JO nucleus and JC nucleus located in the reticular regions surrounding the trigeminal motor nucleus (Vmo; Vmo shell region) were arranged in a topographic fashion, while those in the parabrachial nucleus, supratrigeminal nucleus, lateral reticular formation caudal to the shell region and raphe nuclei were intermingled with each other. The labeling in the individual nuclei was bilateral with an ipsilateral predominance to each injection site, with the exception of the mesencephalic trigeminal nucleus, where the labeling was ipsilateral to the injection site in the JC nucleus. These results, combined with the data of the previous intracellular tracing studies, indicate that based on the presence of somatotopic organization, premotoneurons can be largely divided into two groups; those projecting to either the JO or the JC nucleus and those projecting to the two nuclei, and we offer the suggestion that roles of premotoneurons for jaw movements differ among the individual nuclei.
authors.affiliation: Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Moritani
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chang
authors.forename: Ikuro
authors.initials: I
authors.lastname: Taki
authors.forename: Akiko
authors.initials: A
authors.lastname: Tomita
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ono
authors.forename: Yong-Chul
authors.initials: YC
authors.lastname: Bae
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Shigenaga
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D002415:Cats; D009046:Motor Neurons / Q000166:cytology*; D009434:Neural Pathways / Q000166:cytology*; D014278:Trigeminal Nuclei / Q000166:cytology*