JN Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 80: 715-729, 1998;
0022-3077/98 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lüscher, H.-R.
Right arrow Articles by Larkum, M. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lüscher, H.-R.
Right arrow Articles by Larkum, M. E.

The Journal of Neurophysiology Vol. 80 No. 2 August 1998, pp. 715-729
Copyright ©1998 The American Physiological Society

Modeling Action Potential Initiation and Back-Propagation in Dendrites of Cultured Rat Motoneurons

Hans-R. Lüscher and Matthew E. Larkum

Department of Physiology, University of Bern, CH-3012 Bern, Switzerland

Lüscher, Hans-R. and Matthew E. Larkum. Modeling action potential initiation and back-propagation in dendrites of cultured rat motoneurons. J. Neurophysiol. 80: 715-729, 1998. Regardless of the site of current injection, action potentials usually originate at or near the soma and propagate decrementally back into the dendrites. This phenomenon has been observed in neocortical pyramidal cells as well as in cultured motoneurons. Here we show that action potentials in motoneurons can be initiated in the dendrite as well, resulting in a biphasic dendritic action potential. We present a model of spinal motoneurons that is consistent with observed physiological properties of spike initiation in the initial segment/axon hillock region and action potential back-propagation into the dendritic tree. It accurately reproduces the results presented by Larkum et al. on motoneurons in organotypic rat spinal cord slice cultures. A high Na+-channel density of &gmacr;Na = 700 mS/cm2 at the axon hillock/initial segment region was required to secure antidromic invasion of the somato-dendritic membrane, whereas for the orthodromic direction, a Na+-channel density of &gmacr;Na = 1,200 mS/cm2 was required. A "weakly" excitable (&gmacr;Na = 3 mS/cm2) dendritic membrane most accurately describes the experimentally observed attenuation of the back-propagated action potential. Careful analysis of the threshold conditions for action potential initiation at the initial segment or the dendrites revealed that, despite the lower voltage threshold for spike initiation in the initial segment, an action potential can be initiated in the dendrite before the initial segment fires a spike. Spike initiation in the dendrite depends on the passive cable properties of the dendritic membrane, its Na+-channel density, and local structural properties, mainly the diameter of the dendrites. Action potentials are initiated more easily in distal than in proximal dendrites. Whether or not such a dendritic action potential invades the soma with a subsequent initiation of a second action potential in the initial segment depends on the actual current source-load relation between the action potential approaching the soma and the electrical load of the soma together with the attached dendrites.




This article has been cited by other articles:


Home page
 J. Neurophysiol.Home page
S. Diwakar, J. Magistretti, M. Goldfarb, G. Naldi, and E. D'Angelo
Axonal Na+ Channels Ensure Fast Spike Activation and Back-Propagation in Cerebellar Granule Cells
J Neurophysiol, February 1, 2009; 101(2): 519 - 532.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
W. A. Hossain, S. D. Antic, Y. Yang, M. N. Rasband, and D. K. Morest
Where Is the Spike Generator of the Cochlear Nerve? Voltage-Gated Sodium Channels in the Mouse Cochlea
J. Neurosci., July 20, 2005; 25(29): 6857 - 6868.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
F Saraga, C P Wu, L Zhang, and F K Skinner
Active dendrites and spike propagation in multicompartment models of oriens-lacunosum/moleculare hippocampal interneurons
J. Physiol., November 1, 2003; 552(3): 673 - 689.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
P. D. Dodson, M. C. Barker, and I. D. Forsythe
Two Heteromeric Kv1 Potassium Channels Differentially Regulate Action Potential Firing
J. Neurosci., August 15, 2002; 22(16): 6953 - 6961.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
P. A Rhodes and R. R Llinas
Apical tuft input efficacy in layer 5 pyramidal cells from rat visual cortex
J. Physiol., October 1, 2001; 536(1): 167 - 187.
[Abstract] [Full Text] [PDF]

Home page
 NeuroscientistHome page
M. L. Hines and N. T. Carnevale
Neuron: A Tool for Neuroscientists
Neuroscientist, April 1, 2001; 7(2): 123 - 135.
[Abstract] [PDF]

Home page
 Physiol. Rev.Home page
J. C. Rekling, G. D. Funk, D. A. Bayliss, X.-W. Dong, and J. L. Feldman
Synaptic Control of Motoneuronal Excitability
Physiol Rev, April 1, 2000; 80(2): 767 - 852.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
G. Y. Shen, W. R. Chen, J. Midtgaard, G. M. Shepherd, and M. L. Hines
Computational Analysis of Action Potential Initiation in Mitral Cell Soma and Dendrites Based on Dual Patch Recordings
J Neurophysiol, December 1, 1999; 82(6): 3006 - 3020.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online