title: Neurons in the lateral sacral cord of the cat project to periaqueductal grey, but not to thalamus.
abstract: Previous work of our laboratory has shown that neurons in the lateral sacral cord in cat project heavily to the periaqueductal grey (PAG), in all likelihood conveying information from bladder and genital organs. In humans this information usually does not reach consciousness, which raises the question of whether the lateral sacral cell group projects to the thalamus. After wheatgerm agglutinin-horseradish peroxidase (WGA-HRP) injections into the sacral cord, anterogradely labelled fibers were found in the thalamus, specifically in the ventral anterior and ventral lateral nuclei, the medial and intralaminar nuclei, the lateral ventrobasal complex/ventroposterior lateral nucleus, and the nucleus centre median, lateral to the fasciculus retroflexus. Much denser projections were found to the central parts of the PAG, mainly to its dorsolateral and ventrolateral parts at caudal levels and lateral parts at intermediate levels. In a subsequent retrograde tracing study, injections were made in those parts of the thalamus that received sacral fibers, as found in the anterograde study. Labelled neurons were observed in the sacral cord, but not in the lateral sacral cell group. In contrast, a small control injection in the caudal PAG resulted in many labelled neurons in the lateral sacral cord. These results suggest that afferent information regarding micturition and sexual behaviour is relayed to the PAG, rather than to the thalamus.
authors.affiliation: Department of Anatomy and Embryology, University of Groningen Medical Center, Antonius Deusinglaan 1, bldg 3215, PO Box 196, 9700 AD Groningen, The Netherlands.
authors.forename: Esther Marije
authors.initials: EM
authors.lastname: Klop
authors.forename: Leonora J
authors.initials: LJ
authors.lastname: Mouton
authors.forename: Rutger
authors.initials: R
authors.lastname: Kuipers
authors.forename: Gert
authors.initials: G
authors.lastname: Holstege
mesh_terms: D000344:Afferent Pathways / Q000033:anatomy & histology; D000818:Animals; D001931:Brain Mapping; D002415:Cats; D004525:Efferent Pathways / Q000033:anatomy & histology*; D005260:Female; D007796:Laminectomy / Q000379:methods; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D010487:Periaqueductal Gray / Q000033:anatomy & histology*; D013116:Spinal Cord / Q000166:cytology*; D013788:Thalamus / Q000033:anatomy & histology; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate / Q000378:metabolism
chemical_list: D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate