[FieldTrip] Using clusterstat.m straight giving her specific statobs and statrnd

[Constantino Méndez Bértolo]

Dear Fieldtrippers

We have a 3x3 design and MEG data, say only mag channels (n102) to simplify.

We want to perform a cluster-based permutation approach but
timelockstatistics (cfg.method = 'montecarlo', cfg.correctm = 'cluster',
etc) cannot deal with interactions when you have more than three levels
(true?)

So we built our 'statobs' and 'statrnd' doing a GLM in -R Statistical
Package- and feed 'clusterstat.m' with them

We have done this with one channel over time with success. However, I am
clueless now about how to solve the problem when dealing with the whole
channel set.

I wonder what is the nature of the cfg.dim that we need to feed
'clusterstat.m' with.

Up to now, we use, (cioming out of -R-):

size(statobs) = nchan*ntime % (102*500) % twin = [0 .5] % seconds
size(statrnd) = nchan*ntime*nrandomizations % (102*500*1000)


and the following presets:

cfg=[];
cfg.clustercritval = Fcritmain; % We genereate this before hand
cfg.tail = 1; cfg.clustertail = 1; cfg.clusterthreshold = 'parametric';
cfg.dim = [1 size(statobs,1) size(statobs,2) ] % <<< The key may be here
load('neuromag306mag_neighb.mat');
cfg.neighbours = neighbours;
cfg.feedback = 'yes';
cfg.numrandomization = 1000;
cfg.clusterstatistic = 'maxsum';
cfg.layout = 'neuromag306mag.lay';
for i = 1:length(cfg.neighbours)
cfg.channel{i} = cfg.neighbours(i).label;
end

stat = clusterstat(cfg,statrnd, statobs)


Which lead us to an error within findcluster

Error using findcluster (line 59)
invalid dimension of spatdimneighbstructmat

Error in clusterstat (line 197)
            posclusobs = findcluster(reshape(postailobs,
[cfg.dim,1]),channeighbstructmat,cfg.minnbchan);


If anybody has got some insigth it would be greatly appreciated. Or any
hints. Are the size of my statobs and starnd correct? I can share more
information and firstly apologize  if I was not able to describe the
problem accurately, I am confused regarding that 'reshape' and the addition
of one dimension at "...reshape(postailobs,[cfg.dim,1])...", but the
problem arises first when findcluster.m tries to calculate the size of
spatdimneighbstructmat

First line of findcluster.m calcualtes 'spatdimlength' by : " spatdimlength
= size(onoff, 1);" which in our case is "1", which is obviously wrong?.

manythanks&peace2all

-- 
Constantino Méndez-Bértolo
Laboratorio de Neurociencia Clínica, Centro de Tecnología Biomédica (CTB)

Parque Científico y Tecnológico de la UPM, Campus de Montegancedo

28223 Pozuelo de Alarcón, Madrid, SPAIN
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