title: Static and dynamic membrane properties of lateral vestibular nucleus neurons in guinea pig brain stem slices.
abstract: In vitro intracellular recordings of central vestibular neurons have been restricted so far to the medial vestibular nucleus (MVN). We performed intracellular recordings of large Deiters' neurons in the lateral vestibular nucleus (LVN) to determine their static and dynamic membrane properties, and compare them with those of type A and type B neurons identified in the MVN. Unlike MVN neurons (MVNn), the giant-size LVN neurons (LVNn) form a homogeneous population of cells characterized by sharp spikes, a low-amplitude, biphasic after-hyperpolarization like type B MVNn, but also an A-like rectification like type A MVNn. In accordance with their lower membrane resistance, the sensitivity of LVNn to current injection was lower than that of MVNn over a large range of frequencies. The main difference between LVNn and MVNn was that the Bode plots showing the sensitivity of LVNn as a function of stimulation frequency were flatter than those of MVNn, and displayed a weaker resonance. Furthermore, most LVNn did not show a gradual decrease of their firing rate modulation in the frequency range where it was observed in MVNn. LVNn synchronized their firing with the depolarizing phase of high-frequency sinusoidal current injections. In vivo studies have shown that the MVN would be mainly involved in gaze control, whereas the giant LVNn that project to the spinal cord are involved in the control of posture. We suggest that the difference in the membrane properties of LVNn and MVNn may reflect their specific physiological roles.
authors.affiliation: Laboratoire de Neurobiologie des Réseaux Sensorimoteurs, Centre National de la Recherche Scientifique UMR 7060, Université Paris 5, Centre Universitaire des Saints-Pères, 75270 Paris Cédex 06, France. auno@ent.med.osaka-u.ac.jp
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.forename: Erwin
authors.initials: E
authors.lastname: Idoux
authors.forename: Mathieu
authors.initials: M
authors.lastname: Beraneck
authors.forename: Pierre-Paul
authors.initials: PP
authors.lastname: Vidal
authors.forename: Lee E
authors.initials: LE
authors.lastname: Moore
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Wilson
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vibert
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001933:Brain Stem / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology; D003689:Vestibular Nucleus, Lateral / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D026902:Potassium Channel Blockers; D015221:Potassium Channels