title: Zonal organization of the vestibulocerebellum in pigeons (Columba livia): II. Projections of the rotation zones of the flocculus.
abstract: Previous neurophysiologic research in birds and mammals has shown that there are two types of Purkinje cells in the flocculus. The first type shows maximal modulation in response to rotational optokinetic stimulation about the vertical axis (rVA neurons). The second type shows maximal modulation in response to rotational optokinetic stimulation about a horizontal axis oriented 45 degrees to contralateral azimuth (rH45c neurons). In pigeons, the rVA and rH45c are organized into four alternating parasagittal zones. In this study we investigated the projections of Purkinje cells in the rVA and rH45c zones by using the anterograde tracers biotinylated dextran amine and cholera toxin subunit B. After iontophoretic injections of tracers into the rH45c zones, heavy anterograde labeling was found in the infracerebellar nucleus and the medial margin of the superior vestibular nucleus. Some labeling was also consistently observed in the lateral cerebellar nucleus and the dorsolateral vestibular nucleus. After injections into the rVA zones, heavy anterograde labeling was found in the medial and descending vestibular nuclei, the nucleus prepositus hypoglossi, and the central region of the superior vestibular nucleus. Less labeling was seen in the tangential nucleus, the dorsolateral vestibular nucleus, and the lateral vestibular nucleus, pars ventralis. These results are compared and contrasted with findings in mammalian species.
authors.affiliation: Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada. dwylie@ualberta.ca
authors.forename: Douglas R W
authors.initials: DR
authors.lastname: Wylie
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Brown
authors.forename: Ryan R
authors.initials: RR
authors.lastname: Barkley
authors.forename: Ian R
authors.initials: IR
authors.lastname: Winship
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Crowder
authors.forename: Kathryn G
authors.initials: KG
authors.lastname: Todd
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives*; D002529:Cerebellar Nuclei / Q000033:anatomy & histology / Q000166:cytology; D002531:Cerebellum / Q000033:anatomy & histology* / Q000166:cytology / Q000502:physiology; D002772:Cholera Toxin; D010856:Columbidae; D003911:Dextrans; D007478:Iontophoresis; D009434:Neural Pathways / Q000033:anatomy & histology / Q000166:cytology; D010775:Photic Stimulation; D011689:Purkinje Cells / Q000166:cytology / Q000502:physiology; D014726:Vestibular Nuclei / Q000033:anatomy & histology* / Q000166:cytology
chemical_list: D003911:Dextrans; C076397:biotinylated dextran amine; D001710:Biotin; D002772:Cholera Toxin