how to determine an actionpotential threshold

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Thu, 12/15/2011 - 04:21 am

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

RGerkin wrote:
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.



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