[FieldTrip] EEG Leadfield computation for eyeballs

Wed Feb 18 14:53:06 CET 2026

Hi all,

The Hartmut folks actually have an open (work-in-progress) pull request on the fieldtrip github: https://github.com/fieldtrip/fieldtrip/pull/2253<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Ffieldtrip%2Ffieldtrip%2Fpull%2F2253&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195872897472%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=omR74Ejn01PnBIra5twMlgR3kFHxrZHGyTDWpI5wZHI%3D&reserved=0>. Please feel free to work on this so that we can merge it with the code base. Progress has stalled a bit at this front.

Thus, much of the ’simple’ machinery that is in place in order to create forward models for equivalent current dipoles is already at your disposal in FieldTrip. With an appropriate volume conduction model it should be relatively straightforward to place 2 dipoles at the location of the eyballs, and model the field/potential distribution.

Best wishes,
Jan-Mathijs

On 18 Feb 2026, at 14:07, René Skukies via fieldtrip <fieldtrip at science.ru.nl> wrote:

Dear Thomas,

there was a master student in our Group last year (under the supervision of Benedikt Ehinger & Judith Schepers, in CC) that worked on the topic.

She used the HArtMuT model mentioned by Saran to implement ocular artifacts in EEG simulations. You can find her thesis + code here: https://github.com/s-ccs/2024-ocular-artifacts-simulation/tree/main<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fs-ccs%2F2024-ocular-artifacts-simulation%2Ftree%2Fmain&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195872919488%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=9OPNgZPnaHuAvlhDhM0rAQp7mnsD3FH7XWpTK%2FqV4W8%3D&reserved=0>

The work she did also led to an addition to our simulation toolbox (in Julia), but for now it's still an open PR: https://github.com/unfoldtoolbox/UnfoldSim.jl/pull/165<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Funfoldtoolbox%2FUnfoldSim.jl%2Fpull%2F165&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195872937227%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=e1GoipTVBCs3ByBd1AKGF6Hlf7aemIqdhd3dLw8cxY0%3D&reserved=0>

I am sure you can also write Judith or Bene to discuss this more.

Cheers,
René

On 2/18/2026 1:04 PM, Sarang S. Dalal via fieldtrip wrote:
Dear Thomas,

I haven't tried it myself yet, but check out the HArtMuT model:
 https://www.hartmut.berlin<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fhartmut.neuro.tu-berlin.de%2F&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195872954552%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=fOcQLD%2FC679ws3Gs%2BpNQ03q%2B%2B0KMC0DE%2Fm3VVkynixo%3D&reserved=0>

And associated paper:
http://doi.org/10.1088/1741-2552/aca8ce<https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdoi.org%2F10.1088%2F1741-2552%2Faca8ce&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195872971381%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=I9J%2F27%2FwYliCfTRNRzg2x5XhTj2E0CD6ImfJS9GBIbg%3D&reserved=0>

I'm not sure if it's ready to use with FieldTrip (or EEGLAB) out of the box yet, but maybe with some further hacking/development.

There's probably not much else with available code, but there's several other papers about modelling the oculogram or retinogram, e.g.:
https://doi.org/10.1109/10.552251<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdoi.org%2F10.1109%2F10.552251&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195872990111%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=6G23AKwLK9ZcQ%2BI80P3pVWs3mjrO2GdpHhs7Vf50Qzo%3D&reserved=0>
https://ieeexplore.ieee.org/document/8856323<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fieeexplore.ieee.org%2Fdocument%2F8856323&data=05%7C02%7Cfieldtrip%40science.ru.nl%7C7ec1dca2ecc942181e0a08de6ef50ae5%7C084578d9400d4a5aa7c7e76ca47af400%7C1%7C0%7C639070195873010213%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=qMgcd1sw4VEzPk69Dw3wkG46ML4Mx9DBZSNA9HLguPw%3D&reserved=0>

Depending on what your goal is, I wonder if it might be simpler to 'empirically' determine the ocular lead field with intentional eye movements. Happy to discuss that offline if you like!

Cheers,
Sarang
________________________________
From: fieldtrip <fieldtrip-bounces at science.ru.nl><mailto:fieldtrip-bounces at science.ru.nl> on behalf of Thomas Koenig via fieldtrip <fieldtrip at science.ru.nl><mailto:fieldtrip at science.ru.nl>
Sent: Wednesday 18 February 2026 09:59
To: fieldtrip at science.ru.nl<mailto:fieldtrip at science.ru.nl> <fieldtrip at science.ru.nl><mailto:fieldtrip at science.ru.nl>
Cc: thomas.koenig at unibe.ch<mailto:thomas.koenig at unibe.ch> <thomas.koenig at unibe.ch><mailto:thomas.koenig at unibe.ch>
Subject: [FieldTrip] EEG Leadfield computation for eyeballs

Dear colleagues,

I am looking for a way to compute an EEG lead-field matrix for two single dipoles at the centers of the eyeballs. Has anybody worked on or ideally solved this problem?

Thanks, Thomas

Prof. Dr. Thomas Koenig
Translational Research Center
University Hospital of Psychiatry and Psychotherapy
Bolligenstrasse 111
3000 Bern 60

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