[Eeglablist] CTF275 MEG channel position from FieldTrip to EEGLAB

[Makoto Miyakoshi]

Good to hear that Zhi. And thank you for sharing your solution with others!

Makoto

On Fri, Jul 8, 2022 at 3:50 PM Zhi Li <lizhi.psych at gmail.com> wrote:

> Hi Makoto,
>
> Many thanks for your kind reply. I have solved this problem by adding the
> channel type to *pop_fileio. *
>
> Best wishes,
>
> Zhi
>
> On Fri, 8 Jul 2022 at 17:09, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
>
>> Dear Zhi,
>>
>> I don't have the same experience but I remember I also had some
>> inconvenience with fieldtrip2eeglab for which I needed to modify it a bit.
>> Anyway, it sounds like a low-level technical problem, which I recommend you
>> post to eeglab github issues to let the developers know.
>>
>> https://urldefense.com/v3/__https://github.com/sccn/eeglab/issues__;!!Mih3wA!AShbXpOalytJYyNBenicz3U1qA3DxCYBnVQ8O5jtXMD3GX6wJmHSL8EVomTT7hl7bg4nLYnwC8aRMEF4xG-V2dkZx8c$ 
>> <https://urldefense.com/v3/__https://github.com/sccn/eeglab/issues__;!!Mih3wA!ExFgptOGjSywLmKWBZm34Y3nUDeCVnEamNcPt-4nV17d-Lr_lGmxxIPChGT1wl-4L2zIZ6MguzDiZOnMyCG9LpE$>
>>
>> It may take some time for the developers to take a look at it. Sorry for
>> the inconvenience.
>>
>> Makoto
>>
>> On Fri, Jul 1, 2022 at 2:01 PM Zhi Li <lizhi.psych at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I would like to use ICA and IClabel in EEGLAB to detect artefacts in my
>>> MEG
>>> data. But no matter if I used *fieldtrip2eeglab* or *pop_fileio*, the
>>> gradiometer
>>> channel positions cannot be correctly extracted from the ctf275 .ds
>>> folder.
>>> The channel positions in eeglab format *EEG* are all empty.
>>>
>>> I tried to copy the channel information directly from the header of the
>>> ctf275 data folder but the MEG channels cannot be projected on the 2-D
>>> map
>>> appropriately. It seems like the channel position in the MEG data
>>> imported
>>> by FieldTrip are the real locations of the MEG helmet and their unit is
>>> cm.
>>> whereas the channel position in EEGLAB is based on the 10-10 system which
>>> is already on the scalp. Hence the projected channels on the scalp are
>>> all
>>> misplaced if I use the raw XYZ from the header of ctf275 data.
>>>
>>> May I ask how I could transform the MEG channel position from FieldTrip
>>> to
>>> EEGLAB appropriately, or is there any other solution? Many thanks.
>>>
>>> Best regards,
>>>
>>> Zhi Li
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>>