[Eeglablist] alpha like noise

[Maarten Mennes]

Dear all,

During some of the tasks we used in our lab we encountered a sort of  
alpha-wave-like noise in our EEG-data (see figures in attachment).  
However, subjects were fully awake and had their eyes opened.

This alpha-noise was sometimes stimulus locked as in the attached figure,  
however, most of the time present in clear bursts. In addition this noise  
was not always limited to the posterior channels where you would expect  
the true alpha waves.

We did try a number of techniques in order to filter this noise out, but  
did not succeed. ICA for example could not confine this noise to one  
component.

Has anyone else on this group encounterd this kind of noise in your data  
and if so, what did you do in order to prevent or filter out
these wave-patterns?

Would using more electrodes than the current 19 enable ICA to isolate this  
noise in more confined components?

yours sincerely,
Maarten Mennes

------------------------------
Maarten Mennes
Ph.D. Student
Laboratory for Neuropsychology
Department of Pediatrics
UZ Gasthuisberg, O&N
Herestraat 49
3000 Leuven
Belgium

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

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