[FieldTrip] Urgent: Error in Source Statistics, Group level
Azeez Adebimpe
ayobimpe2004 at hotmail.com
Sun Jan 26 10:43:58 CET 2014
Hi Chaitanya ,
I would suggest you try analyitcs instead of montecarlo and use stat= ft_sourcestatitics(cfg, source1a, source2a .................., source1b,source2b.............);a and b are for the conditions.
Azeez Adebimpe
Date: Sun, 26 Jan 2014 09:46:03 +0100
From: chaitanya.pro at gmail.com
To: fieldtrip at science.ru.nl
Subject: Re: [FieldTrip] Urgent: Error in Source Statistics, Group level
Hi Eelke,
No significant results then in my data. I wonder how my boss takes it :P.
Anyway, thanks for your help on a Sunday that too.
>From your reply I also understand that the code doesn't have any mistakes :)
===============================================
Best RegardsChaitanya Srinivas Lanka
Wiss. Mitarbeiter PhD Student
Functional and Restorative Neurosurgery Neural Information Processing
Neurosurgical University Hospital Graduate Training Center for Neuroscience
Eberhard Karls University Eberhard Karls University
Otfried-Mueller-Str.45 Österbergstr. 3
D-72076 Tuebingen D-72074 Tuebingen
Mobile Phone Number : +49-176-79035731
===============================================
On Sun, Jan 26, 2014 at 9:40 AM, Eelke Spaak <eelke.spaak at donders.ru.nl> wrote:
Hi Chaitanya,
stat.prob reflects the 'p-values' resulting from your statistical test. So voxels expressing e.g. stat.prob < 0.05 should be considered reflecting a significant difference between conditions. The NaNs correspond to voxels outside the brain.
Since stat.mask is all zeros (which by default is just stat.prob < 0.05), this indicates there are no significant differences between your conditions. There is nothing we can help you with in this respect :)
Best,Eelke
On 26 January 2014 09:06, Chaitanya Srinivas <chaitanya.pro at gmail.com> wrote:
Hi Eelke,
I looked at the stat.stat values if that is what you mean. There are some NaNs , but also some values. Similarly in stat.prob, there are some 1's. The stat.mask is all zeros as you say.
Any further suggestions from you?
Thank you
===============================================
Best RegardsChaitanya Srinivas Lanka
Wiss. Mitarbeiter PhD Student
Functional and Restorative Neurosurgery Neural Information Processing
Neurosurgical University Hospital Graduate Training Center for Neuroscience
Eberhard Karls University Eberhard Karls University
Otfried-Mueller-Str.45 Österbergstr. 3
D-72076 Tuebingen D-72074 Tuebingen
Mobile Phone Number : +49-176-79035731
===============================================
On Sun, Jan 26, 2014 at 8:53 AM, Eelke Spaak <eelke.spaak at donders.ru.nl> wrote:
Dear Chaitanya,
Perhaps an obvious question: do you find any significant differences in the statistics step (inspect the stat structure)? If not, the mask will consist of all zeroes, hence giving you a 'blank' plot.
Best,Eelke
On 26 January 2014 08:46, Chaitanya Srinivas <chaitanya.pro at gmail.com> wrote:
Dear fieldtrip users,
I would like to do sourcestatistics on a group level with eeg data. I have a
pre and post intervention measurement for each of my 10 subjects
. After source reconstruction using an DICS beamformer
and volume normalization, I calculated the sourcegrandaverage for the pre and
post condition and i have avg.pow for each subject.
However, when I use the grandaverage results in ft_sourcestatistics in the
configuration shown below and plot the result I just get a blank anatomical
mri. It only runs with cfg.parameter="pow" .I tried with cfg.parameter = 'avg.pow' it doesnt run.
Do I have to set any additional parameters or am I making some mistake?
cfg=[];
cfg.dim = grandAVGsourcePre.dim;
cfg.method = 'montecarlo';
cfg.statistic = 'depsamplesT';
cfg.parameter = 'pow';
cfg.correctm = 'cluster';
cfg.numrandomization = 1000;
cfg.alpha = 0.05;
cfg.tail = 0;
nsubj=length(sourcePre.trial);
cfg.design(1,:) = [1:nsubj 1:nsubj];
cfg.design(2,:) = [ones(1,nsubj) ones(1,nsubj)*2];
cfg.uvar = 1;
cfg.ivar = 2;
stat = ft_sourcestatistics(cfg, grandAVGsourcePre, grandAVGsourcePost);
and next interpolation
cfg = [];
cfg.voxelcoord = 'no';
cfg.parameter = 'mask';
cfg.interpmethod = 'nearest';
cfg.coordsys = 'mni';
mask = ft_sourceinterpolate(cfg,stat,mri);
statplot.mask = mask.mask;
and then for plotting
cfg = [];
cfg.method = 'slice';
cfg.funparameter = 'stat';
cfg.maskparameter = 'mask';
cfg.funcolorlim = [-0.1 0.1];
cfg.opacitylim = [-0.1 0.1];
figure
ft_sourceplot(cfg, statplot);
===============================================
Best RegardsChaitanya Srinivas Lanka
Wiss. Mitarbeiter PhD Student
Functional and Restorative Neurosurgery Neural Information Processing
Neurosurgical University Hospital Graduate Training Center for Neuroscience
Eberhard Karls University Eberhard Karls University
Otfried-Mueller-Str.45 Österbergstr. 3
D-72076 Tuebingen D-72074 Tuebingen
Mobile Phone Number : +49-176-79035731
===============================================
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