[FieldTrip] interpolate missing grad positions

[Schoffelen, J.M. (Jan Mathijs)]

Hi all,

Stephen is totally right. If you’re in for doing a MEG source reconstruction there is no need to interpolate missing channels. The interpolation step does not add new information (it just represents old information in a different way). Also, the introduction of rank deficiency might introduce numerical problems if you don’t deal with that properly.

Best wishes,
Jan-Mathijs

PS: thanks Stephen for teaching me a new verb: to intuit :).

On 4 Oct 2021, at 19:22, Stephen Whitmarsh via fieldtrip <fieldtrip at science.ru.nl<mailto:fieldtrip at science.ru.nl>> wrote:

Hi Fan,

While Julian is of course right, and ft_channelrepair will probably do it for you, I don't think you have to interpolate before doing source modelling: just don't include those channels in your source modelling.

Someone more fluent in the underlying math can chime in, and don't take it from me, but I would intuit that interpolating channels will make your data rank-deficient. I doubt this would pose any real problems though.

Cheers,
Stephen

Op ma 4 okt. 2021 om 19:04 schreef Julian Keil via fieldtrip <fieldtrip at science.ru.nl<mailto:fieldtrip at science.ru.nl>>:
Hi Fan,

ft_channelrepair is what you’re looking for: https://www.fieldtriptoolbox.org/reference/ft_channelrepair/<https://urldefense.com/v3/__https://www.fieldtriptoolbox.org/reference/ft_channelrepair/__;!!HJOPV4FYYWzcc1jazlU!o8oPUVhu488868p0k77GXZEoEu0U1SoRKtrHgdhGfunViqT_gPMhSGQjba5q1qqDVFZc8W9QUeJYzpA$>

Best,

Julian


Am 04.10.2021 um 18:07 schrieb go puluto via fieldtrip <fieldtrip at science.ru.nl<mailto:fieldtrip at science.ru.nl>>:

Hi there,

Does anyone know how to interpolate positions of grad (that were missing at the recording session) for source reconstruction? There are 6 sensors that were not recorded during MEG data collection, is there a function in Fieldtrip to re-interpolate these grad positions? Thanks so much in advance.

best,
Fan
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