[Eeglablist] CTF275 MEG channel position from FieldTrip to EEGLAB

[Zhi Li]

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!ENVD0B0A7NrJL96T7sGAQrAtwDux0_txPuXCxX99zbje1I29MNhYK68zsBi43TXXkwYaFySQPfOo3WBVLZt1D0pc6g$ 
>
> 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
>> _______________________________________________
>> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
>> To unsubscribe, send an empty email to
>> eeglablist-unsubscribe at sccn.ucsd.edu
>> For digest mode, send an email with the subject "set digest mime" to
>> eeglablist-request at sccn.ucsd.edu
>>
>