r.oostenveld at FCDONDERS.RU.NL
Wed Nov 29 09:08:47 CET 2006
On 28 Nov 2006, at 20:05, Hanukaev Dmitri wrote:
> We want to perform a T-dependent statistics test and to find the time-
> space clusters.
> The data has two condition and N replication (12 patient) and was
> acquired using the Loreta software. We used the loreta2fieldtrip.m
> function convert it to a fieldtrip structure.
> Now after the conversion we want to perform the test but we aren't
> which sourcestatistics function to use.
For statistical testing with space-time clusters, you have to use a
non-parametric randomization test. The single sample (voxel/
timepoint) statistic can be a dependent-T value, which then will be
clustered over neighbouring voxels and timepoints. So you should use
sourcestatistics itself, with cfg.method=montecarlo and
The functions sourcestatistics_randomization and
sourcestatistics_randcluster are implemented to test a hypothesis for
single subject source reconstructions in which the data was
randomized between two conditions prior to computing the source
reconstruction. In your case, you want to randomize between
conditions over subjects so these functions do not apply.
Note that 4D clustering (x,y,z,time) is rather experimental, and I am
not sure whether the bookkeeping aspects of the code will work
smoothly. Please read the help of sourcestatistics and of
statistics_montecarlo. Keep us posted on whether it works, and please
do report it if you encounter problems. I suggest that you use the
feature "dbstop if error" in Matlab together with the matlab debugger.
More information about the fieldtrip