[Eeglablist] Fieldtrip Source-localization issues

[Arnaud Delorme]

Dear Ugo,

>  1.  When I plot the source localization, the orientation is 90 degrees wrong. When using dipfit, the activity is correctly localized, but after doing all the dipfit processes – altered to plot frequency – frontal activity is being plot in the right ear. I thought something was wrong, so I artificially increased the activity at channel 12 (the anterior-most channel in my channel model, and the activity is coming from the ear in the eloreta.

Yes, electrodes need to be coregistered with the head model and DIPFIT tries to do that automatically (although you need to check that the alignment is correct).

>  2.  For some reason, fieldtrip won’t accept the atlas. The error says my axis are 10mm in diameter, and the atlas is 150mm in each direction. I’m reading the ROI_MNI_V4 atlas in.

Atlas are specific to source model. You need to use a source model (list of potential brain sources) which have Atlas regions associated with them. In the EEGLAB GUI, you can use DIPFIT to load a source model and its associated Atlas (DIPFIT > Compute leadfield matrix), then use these in Fieldtrip.

Cheers,

Arno