Intrinsic firing dynamics of vestibular nucleus neurons

Chris Sekirnjak, Sascha du Lac

Research output: Contribution to journalArticle

Abstract

Individual brainstem neurons involved in vestibular reflexes respond to identical head movements with a wide range of firing responses. This diversity of firing dynamics has been commonly assumed to arise from differences in the types of vestibular nerve inputs to vestibular nucleus neurons. In this study we show that, independent of the nature of inputs, the intrinsic membrane properties of neurons in the medial vestibular nucleus substantially influence firing response dynamics. Hyperpolarizing and depolarizing inputs evoked a markedly heterogenous range of firing responses. Strong postinhibitory rebound firing (PRF) was associated with strong firing rate adaptation (FRA) and occurred preferentially in large multipolar neurons. In response to sinusoidally modulated input current, these neurons showed a pronounced phase lead with respect to neurons lacking strong PRF and FRA. A combination of the hyperpolarization-activated H current and slow potassium currents contributed to PRF, whereas FRA was predominantly mediated by slow potassium currents. An integrate-and-fire-type model, which simulated FRA and PRF, reproduced the phase lead observed in large neurons and showed that adaptation currents were primarily responsible for variations in response phase. We conclude that the heterogeneity of firing dynamics observed in response to head movements in intact animals reflects intrinsic as well as circuit properties.

Original languageEnglish (US)
Pages (from-to)2083-2095
Number of pages13
JournalJournal of Neuroscience
Volume22
Issue number6
StatePublished - Mar 15 2002
Externally publishedYes

    Fingerprint

Keywords

  • I
  • Phase lead
  • Postinhibitory rebound
  • Potassium current
  • Spike frequency adaptation
  • Vestibular nucleus neuron

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this