Group level sensor space permutation cluster t-test on n channels?

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1

Hi MNE list,

I'm having a bit of trouble on getting group level sensor space stats going. I've run similar in Fieldtrip and just create an array (or matrix in matlab speak) consisting of participants x channels x samples, and looking through the examples it seems we need to work directly with the array data too. But none of the functions I've used seem to accept anything other than a 2d array (3d for TF) and all the examples seem to either be single channel or one sample t-tests.

Are group level stats available currently or does something need to be written / cobbled together to get them to work?

Thanks for any help,

Peter

2

Hi Peter,

Hi MNE list,

I'm having a bit of trouble on getting group level sensor space stats
going. I've run similar in Fieldtrip and just create an array (or matrix in
matlab speak) consisting of participants x channels x samples, and looking
through the examples it seems we need to work directly with the array data
too. But none of the functions I've used seem to accept anything other than
a 2d array (3d for TF) and all the examples seem to either be single
channel or one sample t-tests.

you can use all `mne.stats.permutation_cluster_XXX` functions. They accept
mutli-dimensional arrays as input. Irrespective of the cluster-forming stat
used (t-test, f-test) they will perform a cluster permutation test.
For sensor space data you first have to assemble a corresponding matrix /
array.

X = np.array([e.data for e in m_evoeds])

To yield meaningful results you need to specify a connectivity structure,
e.g., based on the fieldtrip neighbor definitions.
C.f. https://github.com/mne-tools/mne-python/pull/1306 which we recently
added.

The input matrix is then expected to be of size n_subjects, n_times,
n_channels.

HTH,
Denis

Are group level stats available currently or does something need to be

written / cobbled together to get them to work?

Thanks for any help,

Peter

   __________________________
Peter Goodin,
BSc (Hons), Ph.D Candidate.

Brain and Psychological Sciences Research Centre (BPsych)
Swinburne University,
Hawthorn, Vic, 3122

http://www.swinburne.edu.au/swinburneresearchers/index.php?fuseaction=profile&pid=4149

Monash Alfred Psychiatry Research Centre (MAPrc)
Level 4, 607 St Kilda Road,
Melbourne 3004

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3

Dear Denis,

Thank you very much for the code snippet and neighbour definitions advice! As usual the problem was simply user error. My evoked data was being imported and placed into an array of arrays instead of a single multi-dimensional array, so the array object properties (specifically x.ndim) wasn't being assigned.

Peter