[Eeglablist] Questions on FFT phase results and ICA methodology

[Chris Rose]

Hi all,

I am working on a project where we'll be using A.I. to do an exploratory
analysis on recordings taking during the viewing of a stimulus that lasted
~90minutes. Given the length of the recording period and the number of
subjects(60), we are trying to be selective about what information we use
as learning inputs to avoid overloading the AI algorithm.

There are two things that I was hoping to include as inputs in the AI
analysis that I'm having trouble getting.

1) I am hoping to include phase calculations taken from FFT of the standard
frequency bands. We've been using spectopo to calculate the power in each
band, but I don't see any option to calculate phase with this function. This
thread <https://sccn.ucsd.edu/pipermail/eeglablist/2011/003837.html> from a
previous eeglablist question seems to have a similar question, and the
original writer says they solved their problem by using newtimef outputs to
calculate phase for each band/channel, however I'm unclear on how the
post-newtimef calculation would look. Since the data set is so large, I'm
hoping to avoid actually calculating coherence prior to the AI, and simply
let the neural net calculate it internally.

2) A little more unorthodox, I was hoping to include ICA information for
1-minute epochs across the entire recording to see if there are changes in
the predominant components as the stimulus progresses. Trying to simply
segment an EEG file into minutes and run ICA on each segment resulted in a
truly enormous amount of data when testing it with just one subject
(~60GB), and that would certainly be prohibitive to including it in our
analysis. Is there any way that this might be done more efficiently such
that the resulting data is of a mroe manageable size?

Thanks in advance for any thoughts you can offer with either issue!

Best,

Chris
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