Re: question regarding Colocalization Threshold in Fiji - Coloc2

Posted by jo on Jul 29, 2011; 10:00am
URL: http://imagej.273.s1.nabble.com/Re-question-regarding-Colocalization-Threshold-in-Fiji-Coloc2-tp3683647p3683652.html

Dear Daniel,
I have two questions concerning Colocalization threshold and Coloc2 plugin which I´ve been testing lately to analyze my data.

I applied the Colocalization threshold plugin on 2 background-subtracted images for example one “positive” image where colocalization is expected/”visible” and one “negative” image with no colocalized signals. Then, I´ve tested the results with the Colocalization test plugin and all the p values were much lower than 0.
I´ve also tried with Coloc2 and the results (the tM1 and tM2) were extremely different from those of Colocalization threshold. The thresholds were almost the same (Ch1 equal, Ch2 25 instead of 26) but where NO colocalization occurs: Colocalization threshold provides tM1 0,5388 tM2 0,5833 whereas Coloc2 Manders M1 (threshold): 0.836 Manders M2 (threshold): 0.786.
I don´t see the colocalization but the Manders Coefficients from Coloc2 are quite high.
I´d rather use the Colocalization threshold at this point. What do you think about?


On the same pictures the Coloc2 plugin gives me an error:
Warning! y-intercept high - The y-intercept of the auto threshold regression line is high. Maybe you should use a ROI. What is the reason for such a warning and how I can improve my analysis if I don´t want to use a ROI?
Many thanks for your work, I´ll really appreciate any comment/suggestion
J