[Erppcatoolkit-support] ERP-components and PCA-components

[Petter K. <pet...@gm...>]

Hi Joe!
I use your toolkit all the time. I like the structured 

I find that the temporal PCA-components usually have nice correspondance to candidate ERP-components (as you know N400 is my primary interest). However in the spatial decomposition things get problematic: Very often the first spatial component is the best in terms of topography and amplitude, but hardly ever show differences between conditions. Condition differences is usually I usually find in 2 to 4th spatial components, with topographies that does not look like typical ERP-components. (Later spatial components usually captures noise, remaining artifacts etc which is fine). So the mapping between the two-step PCAs and ERP components does not seem to be direct. N400-incongruency effects does not appear, in my data, as a centroparietal negativity. The typical N400-negativity is caputerd in the first component while, incongruency-effect is captured in components with less typical topographies. Is this stuff you recognize Joe? Should I evaluate topographical components as related subcomponents of the same underlying ERP-component rather than as independent ones? And, if the matching between PCA-components and ERP-components is more nested than direct (a unrecognized spatial PC evaluated as part of known and predicted temporal PC) do you have suggestions about how to should do the bonferroni correction?

A second question: What are your views on PARE-correction? I've seen you using it in articles, but it is not a part of the toolkit. 

Hope to have you in Stockholm again in the future!

Best regards!
/Petter Kallioinen