[Eeglablist] Notch filter and minimum #channel for ICA

[Masaki Nishida]

Dear All,
I'm now tackling with the removal of artifacts from sleep EEG.
I would be grateful if anyone could tell me my questions regarding notch 
filtering and application of ICA.

1. I have tried to notch filter to eliminate 60Hz line noise, however, the 
amplitude has remarkably decreased
and the notch noise was unsuccessfully removed in the afterward specttopo().
I am afraid that it could be a kind of bugs of band filter but we are not 
sure.


2. We have intended to apply ICA for our sleep EEG data (sampling rate: 256 
Hz).  Although our data has enough time length for
several hours, it has only four channels so we can get only four ICA 
components.
Could it be unsuitable to run ICA for our data?



Best wishes,


Masaki Nishida M.D.,Ph.D.

Department of Psychiatry, Center for Sleep and Cognition,
Harvard Medical School, Beth Israel Deaconess Medical Center E/FD864
330 Brookline Ave. Boston, MA 02215
phone: 617-667-8452 fax: 617-667-8498
e-mail: mnishida at bidmc.harvard.edu