Consequences of Adaptation of Spike-Threshold-Accommodation

Abstract

Event Abstract Back to Event Consequences of Adaptation of Spike-Threshold-Accommodation William J. Spain1, 2*, Nikolai C. Dembrow1, 2 and Gregory S. Newkirk1 1 University of Washington, Physiology & Biophysics, United States 2 VAPSHCS, Neurology, United States It has long been known that action potential threshold depends on the time-course of the rising trajectory of the underlying EPSCs, so called action potential threshold accommodation where some neurons are less excitable for more slowly rising inputs. By selective filtering of slower inputs, AP threshold accommodation restricts the “synaptic receptive field” of a neuron. Experimental results will be shown demonstrating a dynamic change in the amount of AP threshold accommodation that occurs in a neuron and its consequences for neuronal input selectivity. One of several mechanisms that can result in threshold accommodation is potassium channels located near the spike generating zone of a neuron. The potassium channels must have voltage dependence and kinetics that result in an increase in channel activation during the rising phase of an EPSP (e.g. Id or Kv1 type channels). In some neurons the depolarization of the mean inter-spike membrane potential during persistent firing results in slow inactivation of such K channels. The filtering of slower rising EPSCs decreases over time as K channel inactivation accumulates (all else being equal). In this manner, as synaptic activity persists, a broadening of the range of input frequencies that can efficiently drive action potentials occurs, causing an increase in firing rate. That is, the lessening of threshold accommodation makes the neurons less high pass. In addition to the increase in firing rate, spike-time precision decreases during a constant noisy input (or phase-locking to specific frequency components of the input decreases). A specific example from the auditory brainstem will be reviewed that supports the hypothesis that this form of neuronal adaptation underlies the adaptation of the ability to accurately locate moving sounds. Acknowledgements We thank M. Higgs, S. Slee, M. Kuznetsova, A. Brown and G. Stecker for prior experiments and discussions that formed the basis for this abstract. References Slee, S.L., Higgs, M.H., Fairhall, A.F. and Spain, W.J. Two-Dimensional Time Coding in the Auditory Brainstem. J. Neuroscience 25: 9978-9988, 2005. Kuznetsova, M.S. Higgs, M.H., and Spain, W.J. Adaptive Changes in Firing Rate and Spike Timing Precision in Neurons of the Chick Nucleus Magnocellularis. J. Neuroscience 28:11906-11915, 2008. Higgs, M.H. and Spain, W.J. Kv1 Channels control spike threshold dynamics and spike timing in cortical pyramidal neurons. J. Physiology 589: 5125-42, 2011. Brown, A.D., Kuznetsova, M.S., Spain, W.J. and Stecker, G.C. Frequency-specific, location-independent adaptation of interaural time difference sensitivity. Hearing Research 291: 53-6, 2012. Higgs, M.H. Kuznesova, M.S. and Spain, W.J. Adaptation of spike timing precision controls the sensitivity of sound localization J. Neuroscience 32: 32(44):15489-94, 2012. Keywords: Action potential threshold, Adaptation, Physiological, Potassium Channels, accommodation, Sound Localization, Inactivation, spike time precision, phase-locking Conference: Spike Initiation: Models & Experiments, Prague, Czechia, 22 Jul - 22 Jul, 2015. Presentation Type: Oral Presentation Topic: Neuroscience Citation: Spain WJ, Dembrow NC and Newkirk GS (2015). Consequences of Adaptation of Spike-Threshold-Accommodation . Front. Neurosci. Conference Abstract: Spike Initiation: Models & Experiments. doi: 10.3389/conf.fnins.2015.90.00006 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 07 Jul 2015; Published Online: 08 Jul 2015. * Correspondence: Dr. William J Spain, University of Washington, Physiology & Biophysics, Seattle, Washington, 98195, United States, spain@u.washington.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers William J Spain Nikolai C Dembrow Gregory S Newkirk Google William J Spain Nikolai C Dembrow Gregory S Newkirk Google Scholar William J Spain Nikolai C Dembrow Gregory S Newkirk PubMed William J Spain Nikolai C Dembrow Gregory S Newkirk Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.