[FieldTrip] fft_timelockgrandaverage

[jan-mathijs schoffelen]

Hi all,

Thanks for noticing this discrepancy in the documentation. Indeed when the functionality was changed some time ago, it seems that the wiki was not updated to mirror these changes. But hey, the fun thing about a wiki is that everybody can change it. I hereby give permission to any of you to bring this page up-to-date again ;o).

Best wishes,

Jan-Mathijs


On Sep 22, 2011, at 3:48 PM, Stephen Politzer-Ahles wrote:

> Leopold,
> 
> The way I dealt with this was by running ft_timelockgrandaverage() twice, once with keepindividual='yes' and once with keepindividual='no', and I saved the structures under different names (i.e., 'condition1_grandindividuals' and 'condition1_grandonly'). I used the former one for cluster statistics, and the latter one (which has the .avg field) for plotting. 
> 
> Alternatively, for each grand average structure with individuals you could just create an .avg field by running the following:
> 
> GA.avg = squeeze( mean(GA.individual,1) );
> 
> This should average across individuals.
> 
> Best,
> Steve Politzer-Ahles
> 
> 
> 
> Message: 2
> Date: Thu, 22 Sep 2011 14:49:14 +0200
> From: Zizlsperger Leopold <zizlsperger at gmail.com>
> To: fieldtrip at donders.ru.nl
> Subject: [FieldTrip] ft_timelockgrandaverage
> Message-ID: <058344EB-FCDD-42FB-8A60-E70A339F35F2 at gmail.com>
> Content-Type: text/plain; charset=us-ascii
> 
> Dear Fieldtrippers,
> 
> in a within-subjects design I use ft_timelockgrandaverage with cfg.keepindividual = 'yes' to average timelocked EEG data (10 subjects) of the form:
> 
>  avg: [29x5000 double]
>          var: [29x5000 double]
>         time: [1x5000 double]
>          dof: [29x5000 double]
>        label: {29x1 cell}
>        trial: [172x29x5000 double]
>       dimord: 'rpt_chan_time'
>    trialinfo: [172x28 double]
>          cfg: [1x1 struct]
> 
> I stick closely to the FieldTrip tutorial for cluster permutation statistics. I use the newest version of fieldtrip. After the grandaverage there is no more 'avg' in the structure, so I can not go on in the tutorial e.g. with:
> GA_XvsY = GA_X;
> GA_XvsY.avg = GA_X.avg - GA_Y.avg;
> 
> New data is of structure:
> 
> label: {29x1 cell}
>          time: [1x5000 double]
>    individual: [10x29x5000 double]
>        dimord: 'subj_chan_time'
>           cfg: [1x1 struct]
> 
> Do I get the tutorial wrong or is it my data ?
> Thanks in advance
> Best
> Leopold
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Jan-Mathijs Schoffelen, MD PhD 
Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands
J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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