| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249 2 Department of Mathematics, Ohio State University, Columbus, Ohio 43210 3 Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
Submitted 22 September 2003; accepted in final form 29 December 2003
Subthalamic nucleus neurons exhibit reverse spike-frequency adaptation. This occurs only at firing rates of 20–50 spikes/s and higher. Over this same frequency range, there is an increase in the steady-state frequency–intensity (F–I) curve's slope (the secondary range). Specific blockade of high-voltage activated calcium currents reduced the F–I curve slope and reverse adaptation. Blockade of calcium-dependent potassium current enhanced secondary range firing. A simple model that exhibited these properties used spike-triggered conductances similar to those in subthalamic neurons. It showed: 1) Nonaccumulating spike afterhyperpolarizations produce positively accelerating F–I curves and spike-frequency adaptation that is complete after the second spike. 2) Combinations of accumulating aftercurrents result in a linear F–I curve, whose slope depends on the relative contributions of inward and outward currents. Spike-frequency adaptation can be gradual. 3) With both accumulating and nonaccumulating aftercurrents, primary and secondary ranges will be present in the F–I curve. The slope of the primary range is determined by the nonaccumulating conductance; the accumulating conductances govern the secondary range. The transition is determined by the relative strengths of accumulating and nonaccumulating currents. 4) Spike-threshold accommodation contributes to the secondary range, reducing its slope at high firing rates. Threshold accommodation can stabilize firing when inward aftercurrents exceed outward ones. 5) Steady-state reverse adaptation results when accumulated inward aftercurrents exceed outward ones. This requires spike-threshold accommodation. Transient speedup arises when inward currents are smaller than outward ones at steady state, but accumulate more rapidly. 6) The same mechanisms alter firing in response to irregular patterns of synaptic conductances, as cell excitability fluctuates with changes in firing rate.
This article has been cited by other articles:
|
|
 |
|
  M. N. Miller, B. W. Okaty, and S. B. Nelson Region-Specific Spike-Frequency Acceleration in Layer 5 Pyramidal Neurons Mediated by Kv1 Subunits J. Neurosci., December 17, 2008; 28(51): 13716 - 13726. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Ramanathan, T. Tkatch, J. F. Atherton, C. J. Wilson, and M. D. Bevan D2-Like Dopamine Receptors Modulate SKCa Channel Function in Subthalamic Nucleus Neurons Through Inhibition of Cav2.2 Channels J Neurophysiol, February 1, 2008; 99(2): 442 - 459. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Teagarden, J. F. Atherton, M. D. Bevan, and C. J. Wilson Accumulation of cytoplasmic calcium, but not apamin-sensitive afterhyperpolarization current, during high frequency firing in rat subthalamic nucleus cells J. Physiol., February 1, 2008; 586(3): 817 - 833. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Manuel, C. Meunier, M. Donnet, and D. Zytnicki The afterhyperpolarization conductance exerts the same control over the gain and variability of motoneurone firing in anaesthetized cats J. Physiol., November 1, 2006; 576(3): 873 - 886. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Miocinovic, M. Parent, C. R. Butson, P. J. Hahn, G. S. Russo, J. L. Vitek, and C. C. McIntyre Computational Analysis of Subthalamic Nucleus and Lenticular Fasciculus Activation During Therapeutic Deep Brain Stimulation J Neurophysiol, September 1, 2006; 96(3): 1569 - 1580. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. I. Kass and I. M. Mintz Silent plateau potentials, rhythmic bursts, and pacemaker firing: Three patterns of activity that coexist in quadristable subthalamic neurons PNAS, January 3, 2006; 103(1): 183 - 188. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Manuel, C. Meunier, M. Donnet, and D. Zytnicki How Much Afterhyperpolarization Conductance Is Recruited by an Action Potential? A Dynamic-Clamp Study in Cat Lumbar Motoneurons J. Neurosci., September 28, 2005; 25(39): 8917 - 8923. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. C Loucif, C. L Wilson, R Baig, M. G Lacey, and I. M Stanford Functional interconnectivity between the globus pallidus and the subthalamic nucleus in the mouse brain slice J. Physiol., September 15, 2005; 567(3): 977 - 987. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Atherton and M. D. Bevan Ionic Mechanisms Underlying Autonomous Action Potential Generation in the Somata and Dendrites of GABAergic Substantia Nigra Pars Reticulata Neurons In Vitro J. Neurosci., September 7, 2005; 25(36): 8272 - 8281. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. K. Skinner, J.Y.J. Chung, I. Ncube, P. A. Murray, and S. A. Campbell Using Heterogeneity to Predict Inhibitory Network Model Characteristics J Neurophysiol, April 1, 2005; 93(4): 1898 - 1907. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. J. Magill, A. Sharott, M. D. Bevan, P. Brown, and J. P. Bolam Synchronous Unit Activity and Local Field Potentials Evoked in the Subthalamic Nucleus by Cortical Stimulation J Neurophysiol, August 1, 2004; 92(2): 700 - 714. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Destexhe Is the Purpose of Reverse Spike-Frequency Adaptation to Enhance Correlations? Focus on "A Model of Reverse Spike Frequency Adaptation and Repetitive Firing of Subthalamic Nucleus Neurons" J Neurophysiol, May 1, 2004; 91(5): 1943 - 1944. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
