Adaptation of firing rate and spike-timing precision in the avian cochlear nucleus.
Adaptation is commonly defined as a decrease in response to a constant stimulus. In the auditory system such adaptation is seen at multiple levels. However, the first-order central neurons of the interaural time difference detection circuit encode information in the timing of spikes rather than the overall firing rate. We investigated adaptation during in vitro whole-cell recordings from chick nucleus magnocellularis neurons. Injection of noisy, depolarizing current caused an increase in firing rate and a decrease in spike time precision that developed over approximately 20 s. This adaptation depends on sustained depolarization, is independent of firing, and is eliminated by alpha-dendrotoxin (0.1 microM), implicating slow inactivation of low-threshold voltage-activated K+ channels as its mechanism. This process may alter both firing rate and spike-timing precision of phase-locked inputs to coincidence detector neurons in nucleus laminaris and thereby adjust the precision of sound localization.
Kuznetsova
Marina S
MS
Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98105, USA.
Higgs
Matthew H
MH
Spain
William J
WJ
D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology*; D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001307:Auditory Perception / Q000502:physiology; D001717:Birds / Q000033:anatomy & histology / Q000502:physiology*; D002642:Chick Embryo; D017626:Cochlear Nucleus / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013017:Sound Localization / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D013997:Time Factors
D015221:Potassium Channels