Modeling local field potentials (Bedard et al. 2004)

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Accession:136310
This demo simulates a model of local field potentials (LFP) with variable resistivity. This model reproduces the low-pass frequency filtering properties of extracellular potentials. The model considers inhomogeneous spatial profiles of conductivity and permittivity, which result from the multiple media (fluids, membranes, vessels, ...) composing the extracellular space around neurons. Including non-constant profiles of conductivity enables the model to display frequency filtering properties, ie slow events such as EPSPs/IPSPs are less attenuated than fast events such as action potentials. The demo simulates Fig 6 of the paper.
Reference:
1 . Bedard C, Kroger H, Destexhe A (2004) Modeling extracellular field potentials and the frequency-filtering properties of extracellular space. Biophys J 86:1829-42 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Connectionist Network; Extracellular;
Brain Region(s)/Organism:
Cell Type(s):
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Extracellular Fields;
Implementer(s): Destexhe, Alain [Destexhe at iaf.cnrs-gif.fr];
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LFP
README
ImpedanceFM.mod
calc_lfp_variable-resistivity.oc
curr.dat
mosinit.hoc
                            
Neuron demo file to simulate local field potentials
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This Neuron demo file simulates the model of local field potentials
(LFP) with variable resistivity, as described in the following paper:

 Bedard C, Kroger H and Destexhe A.  Modeling extracellular field
 potentials and the frequency-filtering properties of extracellular
 space.  Biophysical Journal 86: 1829-1842, 2004.

This paper develops a model of LFP that includes the frequency
filtering properties of extracellular space.  The paper considers
inhomogeneous conductivity and permittivity profiles, which results
from the multiple media (fluids, membranes, vessels, ...) composing
the extracellular space around neurons.  Including non-constant
profiles of conductivity enables the model to display frequency
filtering properties, ie slow events such as EPSPs/IPSPs are less
attenuated than fast events such as action potentials.

The model shown here is a reproduction of Figure 6 of the paper. 
The source current is monopolar in this simple case and consists of
an EPSP/IPSP sequence followed by an action potential (see details
in the paper).

The method to calculate the extracellular LFP consists of the 
following steps:
	  - read in the source current I from a data file
	  - compute the Fourier transform of the source current I
	  - compute the impedance Z assuming a non-homogeneous conductivity
	    function (radial symetry) - this step requires a MOD file
	    with the ImpedanceFM mechanism
	  - compute the extracellular voltage by inverse Fourier transform
	    of the product Z(w) * I(w)

Note that this demo file is provided "as is", unfortunately I have
no time to help implementing, but feedbacks are always welcome if
it has been useful to you.  If you use this for your research,
please cite the above paper.

Alain Destexhe, 
CNRS, Gif sur Yvette, France
http://cns.iaf.cnrs-gif.fr

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