first success!!!

Robert Oostenveld r.oostenveld at FCDONDERS.RU.NL
Mon May 8 09:16:26 CEST 2006

> I want to share my first success in using Filedtrip. Although I
> could still not properly load my current 64 electrodes data, I
> succeeded in importing my old 19 channel data. Moreover, I succeded
> in conducting the between-trial clasterrandomization analysis!

It might be that the automatic projection of the 3D electrodes to the
2D surface for plotting is not optimal for your 64 channel set,
perhaps due to a few very low electrodes. I suggest that you
construct a layout file, see my previous mail. You can also look into
the code in private/createlayout, where at the bottom you will find
some code that helps you to  visualise the layout.

> But I still have problems with within-subject cluster-
> randomization. The error "did not find the gradiometer or electrode
> information" appears, line 461. What could it be?

Cluster randomization requires that the neighbourhood geomerty in the
data is known, i.e. the neighbouring electrodes. You can specify them
with cfg.neighbours. It is documented in "help clusterrandanalysis".
One method to automatically specify the neighbourhood is by having
electrode information in the dataset, i.e. an elec structure and to
specify the cfg.neighbourdist option (default is 4 cm, which is
suitable for the CTF gradiometers). I do not know the units of your
electrodes (could be m, cm, mm, or unit-scaled dimensionless), but
the cfg.neighbourdist should be specified in the same units.

best regards,

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