clusterrandanalysis on scalar values + problem with topoplotER
Robert Oostenveld
r.oostenveld at FCDONDERS.RU.NL
Tue Aug 29 23:46:25 CEST 2006
Dear Marco
On 23 Aug 2006, at 14:53, Eric Maris wrote:
>> 2) Is there a way to compute the null distribution by considering
>> all possible reassignments of the conditions instead of the Monte
>> Carlo approximation - in this case it would be feasible because
>> all possible reassignments should be 2^9, right?
> This is not possible with clusterrandanalysis. However, this is
> possible with one of the new statistics functions in Fieldtrip that
> will replace both clusterrandanalysis and sourcestatistics. The
> function of interest for you is timelockstatistics, and you should
> have a look at the help information for the lower-level function
> statistics_montecarlo (which is called by timelockstatistics).
> However, provided that you use more than 500 draws from the
> permutation distribution, don’t expect major changes in the output.
We have an in-house version of fieldtrip, and an external FTP
version. The in-house version is always slightly more advanced than
the external version. Even though the timelockstatistics function was
already included in recent external fieldtrip versions (the daily zip
files) on the Donders FTP server, I just noticed that the underlying
statistics_montecarlo function that Eric is referring to was still
missing from the zip file. I have now also tagged that function (and
some further subfunctions on which it depends) to be released in the
external fieldtrip release. You should be able to use the
timelockstatistics function with both the montecarlo and the complete
permutation (cfg.numrandomization='all') based estimaes for the
cluster statistics.
I hope it works with the new function, if not then don't hesitate to
contact us.
Robert
More information about the fieldtrip
mailing list