how to determine an actionpotential threshold

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Dear all,

that´s a very general question for the determination of a threshold for my measured actionpotentials.
Is there anybody who knows how to do that in Igor or manually?
I read a lot of papers but I´m still confused!

Thanks for your answers!
:-)
The real answer is that there is no such thing as an exact threshold, because the membrane potential increases exponentially. But a robust method for getting something that looks roughly like a threshold is to find the maximum slope of the rising phase, and then locate the point where the membrane potential slope reaches X% of that slope, for some value of X. 10% is usually a reasonable value. You can use, in sequence, Smooth, Differentiate, WaveStats, and FindLevel to achieve your goal. I've written code to do all of this, what I can put on the site if you are interested.

December 16, 2011 at 09:10 pm - Permalink
[quote=RGerkin]The real answer is that there is no such thing as an exact threshold, because the membrane potential increases exponentially. But a robust method for getting something that looks roughly like a threshold is to find the maximum slope of the rising phase, and then locate the point where the membrane potential slope reaches X% of that slope, for some value of X. 10% is usually a reasonable value. You can use, in sequence, Smooth, Differentiate, WaveStats, and FindLevel to achieve your goal. I've written code to do all of this, what I can put on the site if you are interested.[/quote]


Hey,

thanks for your answer. That sounds really good!
It would be very nice if you can put it on the site! I´m at the end of my PhD thesis...time is running out and I´m gonna freak out if I can´t fix that threshold problem :D ;-)

THANK YOU VERY MUCH!!! :)

December 17, 2011 at 09:30 am - Permalink