Subthreshold K+ channel dynamics interact with stimulus spectrum to influence temporal coding in an auditory brain stem model

Mitchell L. Day, Brent Doiron, John Rinzel

Research output: Contribution to journalArticle

Abstract

Neurons in the auditory brain stem encode signals with exceptional temporal precision. A low-threshold potassium current, IKLT, present in many auditory brain stem structures and thought to enhance temporal encoding, facilitates spike selection of rapid input current transients through an associated dynamic gate. Whether the dynamic nature of IKLT interacts with the timescales in spectrally rich input to influence spike encoding remains unclear. We examine the general influence of IKLT on spike encoding of stochastic stimuli using a pattern classification analysis between spike responses from a ventral cochlear nucleus (VCN) model containing I KLT, and the same model with the IKLT dynamics removed. The influence of IKLT on spike encoding depended on the spectral content of the current stimulus such that maximal IKLT influence occurred for stimuli with power concentrated at frequencies low enough (<500 Hz) to allow IKLT activation. Further, broadband stimuli significantly decreased the influence of IKLT on spike encoding, suggesting that broadband stimuli are not well suited for investigating the influence of some dynamic membrane nonlinearities. Finally, pattern classification on spike responses was performed for physiologically realistic conductance stimuli created from various sounds filtered through an auditory nerve (AN) model. Regardless of the sound, the synaptic input arriving at VCN had similar low-pass power spectra, which led to a large influence of I KLT on spike encoding, suggesting that the subthreshold dynamics of IKLT plays a significant role in shaping the response of real auditory brain stem neurons.

Original languageEnglish (US)
Pages (from-to)534-544
Number of pages11
JournalJournal of Neurophysiology
Volume99
Issue number2
DOIs
StatePublished - Feb 2008

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Cochlear Nucleus
Brain Stem
Neurons
Cochlear Nerve
Brain Stem Auditory Evoked Potentials
Potassium
Membranes

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Subthreshold K+ channel dynamics interact with stimulus spectrum to influence temporal coding in an auditory brain stem model. / Day, Mitchell L.; Doiron, Brent; Rinzel, John.

In: Journal of Neurophysiology, Vol. 99, No. 2, 02.2008, p. 534-544.

Research output: Contribution to journalArticle

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