Back to the main page.
Bug 3206 - Tissue confusion in BEM headmodel tutorial
| Status | CLOSED WONTFIX |
| Reported | 2016-11-07 16:41:00 +0100 |
| Modified | 2019-08-10 12:33:05 +0200 |
| Product: | FieldTrip |
| Component: | documentation |
| Version: | unspecified |
| Hardware: | PC |
| Operating System: | Windows |
| Importance: | P5 normal |
| Assigned to: | |
| URL: | |
| Tags: | |
| Depends on: | |
| Blocks: | |
| See also: |
Jens Klinzing - 2016-11-07 16:41:09 +0100
In the BEM tutorial http://www.fieldtriptoolbox.org/tutorial/headmodel_eeg_bem the output of the segmentation is chosen as cfg.output = {'brain','skull','scalp'}; segmentedmri = ft_volumesegment(cfg, mri); Consequently, the order of tissues in the later output of ft_prepare_mesh is also brain, skull, scalp. From Figure 4 onwards, however, the tutorial assumes the scalp to be represented in vol.bnd(1) and the brain in vol.bnd(3), while its actually the other way around. This should affect the code for Figure 4, Figure 5, and the electrode alignment. I wasn't sure enough to edit it directly in the tutorial (dipoli doesn't run on our server), just tell me if I'm correct and I can do the edits.
Robert Oostenveld - 2016-11-07 17:05:08 +0100
(In reply to Jens Klinzing from comment #0) hmm, I recall that there is some reordering of the surfaces. The order is also different for the different MEB methods. So after vol = ft_prepare_headmodel(cfg, bnd); it could very well be that the order has changed. So unless you can show otherwise, I assume that the tutorial is actually correct. You may want to add a warning that the user should check the order, e.g. in the wiki CMS
Jens Klinzing - 2016-11-07 17:18:50 +0100
(In reply to Robert Oostenveld from comment #1) Thanks, I added the warning.
Robert Oostenveld - 2016-11-07 17:21:37 +0100
thanks