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Bug 2429 - Individual BEM, Leadfield and Electrode rotatetd
| Status | CLOSED INVALID |
| Reported | 2014-01-07 15:34:00 +0100 |
| Modified | 2019-08-10 12:28:08 +0200 |
| Product: | FieldTrip |
| Component: | forward |
| Version: | unspecified |
| Hardware: | PC |
| Operating System: | Linux |
| Importance: | P5 critical |
| Assigned to: | |
| URL: | |
| Tags: | |
| Depends on: | |
| Blocks: | |
| See also: |
Julian Keil - 2014-01-07 15:34:54 +0100
Created attachment 579 Indivisual source vs. standard source Dear all, first of all: Happy New Year! I already sent the following issue to the mailing list seeking advise, but without much help (19/12/2013 subject EEG Electrode / Volume Alignment Problem). I also spent more time checking every step in building the BEM and leadfield and doing the source analysis but I'm lost. I uploaded the relevant data (individual MRI, BEM-Model, Leadfield, electrode locations, standard MRI, BEM-Model, Leadfield, electrode locations as well as a sample script) to wetransfer: http://we.tl/7e4T7q0VCY (online until 14/01/14) As I wrote in my mail, I can nicely localize source activity (e.g. visual N1) using the standard BEM, MRI and our standard EEG electrode positions (see Berlin_EEG_Head.mat in the .zip-file from wetransfer). However, when I use the individual MRI (realigned) to build a BEM-Model and then a leadfield and use this for the source analysis, the source appears to be rotated by 90° to temporal cortex. Interestingly, depending on which landmarks I use for the MRI realignment, the sources are shifted clockwise (when using Nasion and Left/Right) or counterclockwise (when using the Commissures). I therefore assume that the alignment in ft_electroderealign between the BEM-Model and the EEG-electrodes fails. Thanks a lot for your help! Julian
Julian Keil - 2014-01-14 11:20:44 +0100
Dear all, sorry to have bothered you. The error seems to have been on this side of the screen: The mesh, volume, grid and leadfield had different units (mm in mesh and volume, cm in grid and leadfield) which I assume caused the problem. I'll double check but hopefully keeping an eye on the units solved my problem. All the best Julian
Jan-Mathijs Schoffelen - 2014-01-15 13:59:36 +0100
Hi Julian, This is JM writing on Nietzsche's bugzilla account: We're changing the status of the bug, since it ssems it's invalid. Feel free to re-open if it remains a problem.