[Eeglablist] Unequal group size and STUDY use

Tue Dec 2 00:32:40 PST 2008

Dear Hamish,

A related problem was that whenever you have channels without  
coordinate, the interpolation function was not functioning. I have  
fixed this problem and I will send you off the eeglablist some  
functions to test that.

In general, I would strongly recommend to use the current version over  
the 6.01 "stable" version of EEGLAB which is more than 1 year and a  
half old.
Best,

Arno

On 2 déc. 08, at 06:36, Hamish INNES-BROWN wrote:

> Interesting, it's working really well for me - I'm very glad!
>
> I did have to ensure that the interpolation was done correctly  
> though.  For me this meant using the stable v6.01 to do JUST the  
> interpolation, saving the STUDY, and then going back to the Oct08  
> version to pre-calculate my channel measures.  Then the plotting of  
> channel measures with unequal group sizes (and I also have two  
> conditions) works fine as far as I can see.
>
> I never did work out why the interpolation didn't work correctly in  
> the newer versions.  I tried many different parameters using  
> std_interp, eeg_interp as well as the menu system, and always ended  
> up with an error  (griddata error previously reported).
>
> Anyway that's what worked for me - do interpolation in the stable  
> version of eeglab (v6.01), then calculate channel measures in the  
> oct08 version, and then plotting will work.  Probably there is an  
> easier way :)
>
> It looks like what you did should have worked though, are you  
> definitely using the edited version of std_erpplot.m?  I have a few  
> different eeglab directories on my PC and it's easy to start up from  
> the wrong one..
>
> Hamish Innes-Brown
> Senior Research Assistant
>
> The Bionic Ear Institute
> c/o St Vincents Hospital
> 6th Floor Daly Wing,
> 35 Victoria Pde, Fitzroy Vic 3065
> Tel: +61 3 9288 3523
> Fax: +61 3 6997 7518
>
>
>
> From: Hilla Jakoby [mailto:jakobyhi at yahoo.com]
> Sent: Tuesday, 2 December 2008 2:59 AM
> To: Hamish INNES-BROWN; arno delorme
> Cc: eeglablist at sccn.ucsd.edu; Michael Stevens
> Subject: Re: [Eeglablist] Unequal group size and STUDY use
>
>
> Dear all,
>
> I've tried to use the new std_erpplot.m function with an unequal  
> number of subjects of each group (25 versus 29) and the same error  
> message was generated when trying to plot their ERPs as before  
> (using the old function). I've interpolated all datasets beforehand  
> to 65 electrodes (using eeg_interp(EEG, chanlocs,'invdist'). was I  
> right in doing so?
> On equal group sizes STUDY works well.
> Is there another solution for the problem, other changes to be done?
> Many thanks, Hilla
>
>
> Ph.D. student
> Gonda brain reseach center,
> Bar Ilan Universiy, Israel
>
>
>
>
> --- On Sun, 11/30/08, arno delorme <arno at ucsd.edu> wrote:
> From: arno delorme <arno at ucsd.edu>
> Subject: Re: [Eeglablist] Unequal group size and STUDY use
> To: "Hamish INNES-BROWN" <HINNES-BROWN at bionicear.org>
> Cc: eeglablist at sccn.ucsd.edu, "Michael Stevens" <msteven at harthosp.org>
> Date: Sunday, November 30, 2008, 9:40 PM
>
> Dear Michael and Hamish,
>
> thanks for reporting the problem. This issue arises due to the  
> complexity of
> the scheme implemented to handle scalp map plotting in the case of  
> subject with
> different number of channels. This scheme was currently enforcing to  
> have groups
> of the same size. To fix this problem, I have decided to enforce  
> interpolation
> so that all subject will need to have the same number of channels  
> (or at least
> subset of channels when plotting scalp maps). Scalp maps where the  
> different
> channels average different numbers of subjects do not make much  
> sense anyway.
> There has also been at least two people reporting plotting problems  
> after
> interpolating data, although I have not yet myself been able to  
> reproduce the
> problem. I hope the current fix will solve this problem too.
>
> I have reprogrammed the attached std_erpplot.m function so that it  
> can handle
> groups of different sizes (although be sure to interpolate missing  
> channels).
> Please let me know if this fixes your problems (just replace this  
> function in
> the eeglabxxx/functions/studyfunc/ folder) and it will be integrated  
> in the
> EEGLAB monthly release. This message was forwarded to the list  
> because it is of
> global interest and also because it depicts a problem that is a  
> major current
> limitation for most users. In general though, please use the  
> Bugzilla database
> for reporting problems.
>
> Best,
>
> Arno
>
> ps: For interpolation, there is currently a non-documented bug: if you
> interpolate channels when pre-computing ERPs and then go back to the  
> pre-compute
> GUI to compute ERSP without interpolation, the function will crash.  
> This is
> because all measure have to be consistent in terms of interpolation.  
> As
> described above, the future function will enforce interpolation  
> (which is
> relatively fast). In case the function crashed for you, erase all  
> measure data
> files (*.daterp, *.datersp, *.datspec, *.datitc), and type on the  
> command line
> STUDY.changrp = []; then call back the pre-computing interface.
>
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