AW: [Eeglablist] alpha like noise

Ian Kirk i.kirk at auckland.ac.nz
Wed Oct 19 13:55:14 PDT 2005


All v. good refs 
-you might want to look at Worden et al., J. Neurosci 20 RC63, 2000 
too.

cheers,
Ian

On 19 Oct 2005 at 9:16, Sarnthein Johannes wrote:

> Hi Maarten,
> You are probably looking at real data, leave it in.
> There are several reports of cognitive alpha processes,
> for example in expectancy and also working memory.
> See some references below.
> Best,
> Johannes
> 
> Petsche H, Kaplan S, von Stein A, Filz O.
> The possible meaning of the upper and lower alpha frequency ranges for
> cognitive and creative tasks. Int J Psychophysiol. 1997
> Jun;26(1-3):77-97.
> 
> Von Stein et al.
> http://www.pnas.org/cgi/content/full/97/26/14748
> 
> von Stein A, Sarnthein J.
> Different frequencies for different scales of cortical integration:
> from local gamma to long range alpha/theta synchronization. Int J
> Psychophysiol. 2000 Dec 1;38(3):301-13
> 
> Jensen et al
> http://cercor.oxfordjournals.org/cgi/content/full/12/8/877
> 
> Klimesch Group
> 
> Basar Schurmann Group
> 
> and some others
> 
> 
> 
> 
> 
> -----Ursprüngliche Nachricht-----
> Von: eeglablist-bounces at sccn.ucsd.edu
> [mailto:eeglablist-bounces at sccn.ucsd.edu] Im Auftrag von Maarten
> Mennes Gesendet: Dienstag, 18. Oktober 2005 11:32 An:
> eeglablist at sccn.ucsd.edu Betreff: [Eeglablist] alpha like noise
> 
> 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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> 
> 
> 
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Ian Kirk, PhD
Senior Lecturer, 
Research Centre for Cognitive Neuroscience,
Department of Psychology,
University of Auckland, Private Bag 92019, 
Auckland, New Zealand.
Tel: (09)373-7599 X 88524(office) 88421(lab)
Fax:(09)373-7450
e-mail: i.kirk at auckland.ac.nz




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