There existed a bug until recently (fixed on Dec 6, 2018) when reading CTF recordings with a headshape .pos file that would introduce an error in MEG coil orientations on the order of 1%. These errors would propagate to the forward and inverse solutions and thus affect any results in source space.

For users currently analyzing data where the bug is present, we created a process (added Jan 18, 2019) that can reset a channel file while keeping existing projectors and history, to avoid having to restart analysis from zero. This short tutorial shows how to fix data already read and pre-processed in Brainstorm.

If you choose to proceed with fixing your data, understand that all existing data including and past computing a forward model will have to be discarded and recomputed.

The process will also work best if the original raw data is still available in the same location as when it was first read into Brainstorm. If this is no longer the case and the raw files cannot be put back in their original location for some reason, the process will prompt to select each channel file manually.

First, make sure your copy of Brainstorm is up to date.