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zaza_DG
USA
2 Posts |
 Posted - 11/16/2005 : 1:55:12 PM
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I am trying to find out probability of release of a transmitter in a central GABAergic synapse. I am wondering if anyone uses Origin to perform variance-mean analysis of amplitude of synaptic currents to construct parabola and find out P (according to method of John Clements).
If you know how to do this kind of analysis with Origin, please email me at zm5e@virginia.edu. I will greatly appreciate.
Thanks,
Zaza
University of Virginia |
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minimax
348 Posts |
Posted - 11/17/2005 : 05:07:48 AM
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Hi Zaza,
Currently, Origin does not directly provide the variance-mean analysis tool. However, I notice that the analysis is based on a simple parabola (y = A*x - B*x^2) fitting. Hence , you could perform the analysis by hand.
1.Firstly, supporse that you have calculated out the variances and means of amplitude under different release probability conditions.
2. Use NLSF tool to fit the user-defined parabola function: y = A*x - B*x^2, where y represnets variance of amplitude of synaptic currents, and x represents mean amplitude.
3. Use estimated parameters A and B to calculate desirable parameters:
3.1) The average amplitude Qav = A/(1 + c.v.^2).
3.2) The average probability Pr = (B/A)*(1 + c.v.^2).
3.3) The lower limit number of measurements Nmin = 1/B.
where c.v. is the coefficient of variation of the amplitude.
Note: Since here I can not find out the original article form John Clements, the above formulas maybe have slight mistakes. If you are familiar with it, just correct it and let me know.
Max
OriginLab GZoffice
Edited by - minimax on 11/17/2005 05:10:06 AM |
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Using Origin for variance-mean analysis