[Eeglablist] (Updated) Huge challenge: Dipoles uncorrelated with components

[Delorme, Arnaud]

Hi Curtis,

I agree with Makoto. The issue is the coregistration. Your head model is not aligned with your electrode. See this section of the tutorial for more information.

https://sccn.ucsd.edu/wiki/A08:_DIPFIT#Manual_coregistration_or_fine_tuning_of_coregistration

Best wishes,

Arno

> On Jul 2, 2020, at 8:09 AM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
> 
> Dear Curtis,
> 
> This seems a common failure that coregistration between the forward head
> model and your electrode locations is erroneously set to be 90 degrees
> rotated.
> I updated my Wiki page to describe the meaning of head model coregistration.
> 
> https://sccn.ucsd.edu/wiki/Makoto%27s_preprocessing_pipeline#Head_model_coregistration
> 
> 
> Makoto
> 
> On Tue, Jun 30, 2020 at 11:26 PM Curtis Bingham <cnbingham at gmail.com> wrote:
> 
>> (UPDATE with links to images, and additional information in UPDATES
>> section below, as requested by kind souls who responded privately)
>> 
>> 
>> 
>> Why are my dipoles completely uncorrelated with independent components?
>> 
>> In this image (
>> https://urldefense.com/v3/__https://imgur.com/wlHSs0X__;!!Mih3wA!W92KXdh7blda6IzoYtjvGjRu6xaTeySMzUMtOXyW_F1oJlZEaDjOLADtJxU5Hp4eJLIK6g$
>> ), you can see that the dipoles representing the components are almost
>> entirely uncorrelated with the independent components.
>> The dipole for IC 7 is the only dipole properly correlated with the
>> underlying component
>> Dipoles for IC 2 and IC 9 are in opposite hemispheres from the components
>> The remaining dipoles are a LONG way away from their components.
>> 
>> 
>> What would cause this extreme separation of dipole from independent
>> component?
>> 
>> 
>> 
>> The EDF file is generated by Neurofield Q20 and processed as follows:
>> import, channel locations (10-20 or 10-05 locs file makes no difference)
>> average reference, remove baseline, high and low-pass filter, runica,
>> ICLabel, and delete rejected components.
>> 
>> 
>> 
>> DIPFIT is run with Template BEM (MNI), no co-reg, autofit (RV%=100)
>> 
>> There is a warning in each pass saying “use cfg.headmodel instead of
>> cfg.hdmfile” but that is hardcoded in the dipfit code.
>> 
>> 
>> 
>> In this image (
>> https://urldefense.com/v3/__https://imgur.com/P8CvQA3__;!!Mih3wA!W92KXdh7blda6IzoYtjvGjRu6xaTeySMzUMtOXyW_F1oJlZEaDjOLADtJxU5Hp5QVil1qw$
>> ) you can see the DIPFIT plot with the RV% and TAL numbers:
>> 
>> 
>> 
>> 
>> 
>> I’ve used the same EDF dataset and tested eeglab 2019_0 against 2019_1,
>> and within each of those trials, have tested DIPFIT 3.0 and 3.3, but
>> haven’t been able to find any combination wherein the dipoles actually
>> matched the components, most likely ruling out a version mismatch.
>> 
>> 
>> 
>> What are we doing wrong? Can anyone shed some light on what might be
>> happening and how we can attempt to further diagnose?
>> 
>> 
>> 
>> Updates:
>> 
>> Someone suggested plotting the channels to ensure that channels aren’t
>> being transposed somehow. It appears that the channels are being properly
>> referenced and sequenced.
>> 
>> This image (
>> https://urldefense.com/v3/__https://imgur.com/ByfaSYi__;!!Mih3wA!W92KXdh7blda6IzoYtjvGjRu6xaTeySMzUMtOXyW_F1oJlZEaDjOLADtJxU5Hp69f1htbg$
>> ) shows the layout of the channels. Ignoring the pre- and post-fix labels,
>> these appear to be in the correct order and placement in the 10-20 system.
>> These are obtained in the channel locations dialog from the
>> eeglab2019_1/sample_locs/Standard-10-20-Cap19.ced file that I’ve merely
>> changed the labels so I don’t have to manually edit every channel name.
>> 
>> 
>> 
>> Without going too far down a rabbit hole, when I plot the channel layout
>> obtained from the plugins/dipfit/standard_BEM/elec/standard_1005.elc, I get
>> a plot where the ears (T3/T4) are too low, and the Fp1/Fp2 are too far
>> forward and off the head (
>> https://urldefense.com/v3/__https://imgur.com/dlp8KEw__;!!Mih3wA!W92KXdh7blda6IzoYtjvGjRu6xaTeySMzUMtOXyW_F1oJlZEaDjOLADtJxU5Hp52heQLlw$
>> ). Is that expected behavior?
>> 
>> 
>> 
>> 
>> 
>> Suggestions welcome!
>> 
>> 
>> 
>> Best regards,
>> 
>> Curtis
>> 
>> 
>> 
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