Borg-Graham Type Channel

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Borg-Graham Type Channel

Post by lb5999 »

I am having trouble finding literature accurately describing a "Type" of channel that seems to be popular on the senselab website. Michael Hines himself uses a .mod file for the potassium A-current that quotes the description at the top of the file:
"Borg-Graham type generic K-A channel" (bgka.mod) ... eadme.html

I noticed that the style of modelling the channel differs slightly from other methods:
1) The time constants take on a different shape (in HH models they have the shape 1/alpha+beta).
2) n - the activation gating variable - occurs as a single power only in the formula for conductance (whereas, in the Connor-Stevens model for the A-current, for example, it occurs as a cube. It has even been seen to occur as a quartic in some models on senselab).
3) There are parameters I don't recognise, namely a0l_bgka and a0n_bgka.

I was wondering if anyone knew what modelling process resulted in this .mod file? Can anyone give me a break down of how it works, what it is and why people prefer to use it over the standard HH method.


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Re: Borg-Graham Type Channel

Post by ted »

Fair question. The best answer I can provide is to refer you to the following:

Borg-Graham, L., Modelling the non-linear conductances of excitable membranes. In Cellular Neurobiology: A Practical Approach, edited by Chad, J. and Wheal, H. pp247-275. IRL Press at Oxford University Press, 1991.

And Chapter 4 in
Borg-Graham, L., Modelling the somatic electrical behavior of hippocampal pyramidal neurons. Master's Thesis, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 1987 (Also appears as MIT AI Lab TR 1161)

The latter document is available from a link at
http://neurophys.biomedicale.univ-paris ... -pubs.html
and chapter 4 isn't the only part of it that is well worth reading.
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