[Eeglablist] cohangle distribution

Scott Makeig smakeig at ucsd.edu
Mon Apr 4 10:18:00 PDT 2005


The computations performed in crossf() are documented in the J Neurosci 
Methods paper (Delorme & Makeig, 2004). There are four modes (linear 
coherence or phase coherence, with or without the ERP).

The data save option you are looking for is present but hidden in the 
current version of crossf(). Add flag/arg pair  'savecoher',1 to your 
call - then the last listed output, 'cohangles', will have the 
single-trial cross-spectral vectors. I have  documented this option - if 
will be in the next release, but should work  with the current version.

Scott

Joseph Brooks wrote:

> Hi All,
>
> I am working with the cohangle outputs from CROSSF. My question is 
> about how exactly the angle that is output is computed. I'm assuming 
> that it is computed as the angle of the vector sum of all of the 
> individual trial phase differences. Is this true? I understand that 
> the coherence is essentially the normalized length of the vector sum.
>
> Also, I am interested in looking at the actual distribution of those 
> individual trial phase differences. I can't find an option to output 
> this. Has anyone else modified the code of crossf to access this 
> information? If so, I'd be interested in seeing your modifications or 
> just a description of where in the code to focus. Any help will be 
> much appreciated.
>
> Joe
>



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