[Mne_analysis] permutation clustering test using TFCE

Laetitia Grabot laetitia.grabot at gmail.com
Thu Jul 31 04:03:37 EDT 2014
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Hi Denis,

I tried the spatio-temporal clustering with TFCE
(spatio_temporal_cluster_1samp_test) on alpha power data (size of epoch :
2s; decimation = 4 (so 501 time points)) with n_jobs = 6 and the default
TFCE parameter (dict(start = 0, step = 0.2)).
According to script output, 48 thresholds were used from 0 to 9.4.
After 5h (!!), 10262484 clusters were found and finally after some others
hours the script crashed before the end ("cannot allocate memory")...

I tried on shorter data (1s so 250 time points) but it was also too long
and too memory-demanding. Then I tried to change the step parameter to
decrease the number of thresholds to test. I took step =0.5. 17 thresholds
were used from 0 to 8. 5121000 clusters were found and my script also ended
up crashing. So... what do you suggest to get acceptable computation time?

By the way, with p_threshold =0.001, I got no cluster; with  p_threshold
=0.01, I got one occipito-parietal cluster (pvalue = 0.026) lasting around
500ms, after something about 10min of computation.

Hoping that it is useful for you,
Laetitia G.
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