[FieldTrip] doing ica on magnetometers and gradiometers

[Thomas Hartmann]

hi,

we have had a vivid discussion in our group concerning whether apply ICA 
to magnetometers and gradiometers in one go (i.e. lumping them together) 
or whether it is necessary to apply the ICA on mags ands grads 
separately. most approaches that can be found on the internet seem to 
favor the do-it-in-one-go way.

my main concern with applying it to both sensor types at the same time 
is that the resulting components will probably be a linear mixture of 
both sensor types. when i reject some components and the project the 
components back to the sensor space, gradiometer activity should "leak" 
into the magnetometer data and vice versa.

or am i wrong with my thoughts? or does it just not matter at all?

i am looking forward to reading your thoughts!

best,
thomas

-- 
Dr. Thomas Hartmann

Centre for Cognitive Neuroscience
FB Psychologie
Universität Salzburg
Hellbrunnerstraße 34/II
5020 Salzburg

Tel: +43 662 8044 5109
Email: thomas.hartmann at th-ht.de

"I am a brain, Watson. The rest of me is a mere appendix. " (Arthur Conan Doyle)