[FieldTrip] ICA on MEG data

[Irina Simanova]

Dear FieldTripers,

I would like to identify ocular artifacts in an MEG dataset using the  
ICA.

The data consist of 180 trials of variable duration ( the signal from  
stimulus onset to subject's response). The trials' duration vary from  
400 ms to 3000 ms. The data is sampled at 1.2 kHz, and has 275  
channels. I am new to ICA, and I need a piece of advice. What would be  
a reasonable number of output independent components?
Should I do the PCA as a pre-processing stage? How do i find an  
optimal number of principal components to extract?

I would appreciate your help,

Kind regards,

Irina Simanova
PhD student
Neurobiology of Language Group
Max-Planck Institute for Psycholinguistics
Wundtlaan 1
6525 XD Nijmegen
The Netherlands
e-mail: irina.simanova at mpi.nl
phone: +31 24 3521541