The Journal of Neuroscience, July 23, 2008, 28(30):7476-7491; doi:10.1523/JNEUROSCI.4198-07.2008
Previous Article | Next Article 
Cellular/Molecular
Channel Density Distributions Explain Spiking Variability in the Globus Pallidus: A Combined Physiology and Computer Simulation Database Approach
Cengiz Günay, *
Jeremy R. Edgerton, * and
Dieter Jaeger
Department of Biology, Emory University, Atlanta, Georgia 30322
Correspondence should be addressed to Dr. Dieter Jaeger, Department of Biology, 1510 Clifton Road, Atlanta, GA 30322. Email: djaeger{at}emory.edu
Globus pallidus (GP) neurons recorded in brain slices show significant variability in intrinsic electrophysiological properties. To investigate how this variability arises, we manipulated the biophysical properties of GP neurons using computer simulations. Specifically, we created a GP neuron model database with 100,602 models that had varying densities of nine membrane conductances centered on a hand-tuned model that replicated typical physiological data. To test the hypothesis that the experimentally observed variability can be attributed to variations in conductance densities, we compared our model database results to a physiology database of 146 slice recordings. The electrophysiological properties of generated models and recordings were assessed with identical current injection protocols and analyzed with a uniform set of measures, allowing a systematic analysis of the effects of varying voltage-gated and calcium-gated conductance densities on the measured properties and a detailed comparison between models and recordings. Our results indicated that most of the experimental variability could be matched by varying conductance densities, which we confirmed with additional partial block experiments. Further analysis resulted in two key observations: (1) each voltage-gated conductance had effects on multiple measures such as action potential waveform and spontaneous or stimulated spike rates; and (2) the effect of each conductance was highly dependent on the background context of other conductances present. In some cases, such interactions could reverse the effect of the density of one conductance on important excitability measures. This context dependence of conductance density effects is important to understand drug and neuromodulator effects that work by affecting ion channels.
Key words: basal ganglia; model; excitability; ion channel; in vitro; neuron
Received Sept. 13, 2007;
revised May 26, 2008;
accepted June 11, 2008.
Correspondence should be addressed to Dr. Dieter Jaeger, Department of Biology, 1510 Clifton Road, Atlanta, GA 30322. Email: djaeger{at}emory.edu
Related articles in J. Neurosci.:
- This Week in The Journal
J. Neurosci. 2008 28: i.
[Full Text]
This article has been cited by other articles:

|
 |

|
 |
 
C. Gunay and A. A. Prinz
Model Calcium Sensors for Network Homeostasis: Sensor and Readout Parameter Analysis from a Database of Model Neuronal Networks
J. Neurosci.,
February 3, 2010;
30(5):
1686 - 1698.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. A. Deister, C. S. Chan, D. J. Surmeier, and C. J. Wilson
Calcium-Activated SK Channels Influence Voltage-Gated Ion Channels to Determine the Precision of Firing in Globus Pallidus Neurons
J. Neurosci.,
July 1, 2009;
29(26):
8452 - 8461.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. L. Taylor, J.-M. Goaillard, and E. Marder
How Multiple Conductances Determine Electrophysiological Properties in a Multicompartment Model
J. Neurosci.,
April 29, 2009;
29(17):
5573 - 5586.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
N. Keren, D. Bar-Yehuda, and A. Korngreen
Experimentally guided modelling of dendritic excitability in rat neocortical pyramidal neurones
J. Physiol.,
April 1, 2009;
587(7):
1413 - 1437.
[Abstract]
[Full Text]
[PDF]
|
 |
|