[Eeglablist] "Subtract individual subject mean spectrum"--- What does this option do??

[SANKET JAIN]

Hello,

I have created a .study file which has 9 datasets for 2 conditions (total 18
files). I am interested in knowing any significant differences in the
topographic maps for a particular frequency (say 15 hz).

In the Study tab, I used the "Precompute channel measure" to precompute the
power spectrum for this .study file. Then I used "Plot channel measures" to
plot the topographic maps for a particular frequency.  In "Plot channel
measures", there is a button "Params" between "Plot Spectra". When I press
"Params", I get the option "*Subtract individual subject mean spectrum*". I
get a different result when I select and not select this particular option.

I want to know, what exactly this options does? When I looked at the
frequency graphs using this option selected, the morphology of the frequency
graphs changes compared to when the option is not selected.

I looked in the manual but I think its not mentioned there. So, can anyone
explain me more about the option "*Subtract individual subject mean
spectrum"*

-- 
Sanket G. Jain
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