No subject

Jan Mathijs Schoffelen Jan.Schoffelen at FCDONDERS.RU.NL
Mon Feb 12 08:43:23 CET 2007


Hi Sameer,

To start with your last question:

>Finally, while trying to see the spatial topography of the signals,
>using
> 	>> lay = createlayout('neuromag306.lay');
>gives me error
> 	??? Undefined command/function 'createlayout'
>even though the createlayout.m file exists in the private folder. (I am
>aware this might be a matlab problem and am looking into that too.)

The problem you mention is probably due to the fact, that createlayout is
inside the private-folder. M-files which are located within the folder which
contains the private-folder, have access to the functions which are private.
However, private functions cannot be accessed from the command-line. You
might try copying createlayout to a location which is on your matlab-path
and retry the command.

>After doing (from
>http://www2.ru.nl/fcdonders/fieldtrip/doku.php?id=fieldtrip:documentation:u
>se_independent_component_analysis_ica_to_remove_ecg_artifacts)
>
> 	 comp  = componentanalysis(cfg, data);
>
>what command can I use in order to visually identify which
>components I should remove, In other words, how do I plot the components
>(like in EEGlab) before I can use the command to remove the components?

Identifying the artifactual components can be done in a variety of ways:
1 you can plot the spatial topography, as specified in comp.comp. Artifacts
often have a typical topography.
2 if you recorded an ECG-channel you can compute a QRS-complex triggered
average, to identify those components being ECG-like. (Or similarly, you can
compute coherence between the external ECG and your components).
3 eye-movements and muscle artifacts betray themselves by their spatial
topography and time course.

Yours,

Jan-Mathijs



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