[Eeglablist] Adjar Technique

[Scott Makeig]

Anja - While you look for existing Adjar code, I suggest you trying
visualize your data trials using erpimage(), for example sorted by subject
reaction time. Then you can see directly 'what' features are time-locked to
the stimulus onset, and 'what' to the subject response. Of course, if you
visualize the channel data directly, keep in mind that each channel is a
weighted sum/difference of several cortical source activities, with little
or no sign of 'what' features come from 'which' in the individual channel
records. Several examples of using erpimage plotting to explore
'trial-by-trial' data relationships in evoked response data trials are
presented the chapter Julie Onton and I wrote last winter for a Steve Luck
edited handbook:

http://sccn.ucsd.edu/~scott/pdf/MakeigOnton_ERP09.pdf

In fact, simple Adjar code could be written in Matlab using the outputs of
erpimage. A plug-in wouldn't be hard for an experienced Matlab script writer
to manage, and might include step-by-step erpimage visualizations. For
example, at every iteration, a 2-by-4 matrix of erpimage plots could show

stim-aligned_data   stim-aligned_data_            stim-aligned_ERP_data_
      resp-aligned_ERP_
                               with_ERPs_removed         removed_from_each_
           data_rmd_from_each_

stim-aligned_trial                     stim-aligned_trial

resp-aligned_data   resp-aligned_data_           stim-aligned_ERP_data_
     resp-aligned_ERP_
                                with_ERPs_removed
removed_from_each_trial      data_rmd_fr_ea_tr

resp-aligned_trial                   resp-aligned_trial

Sorry if this is beyond your current ability or outside your interest -- I'm
hoping someone on the list
may want to try it...

Scott Makeig



Scott

On Tue, Nov 17, 2009 at 9:44 AM, Dr. Anja Ischebeck <
anja.ischebeck at uni-graz.at> wrote:

> Dear all,
>
> We am currently trying to use the Adjar technique
> (Woldorff, Psychophysiology, 1993),
> to deal with overlapping ERP Responses.
> However, I am not quite able to wrap my head
> around it. Does anybody have some experience
> with Adjar? Every bit of script would help us,
> just as a demo of what has to be done.
>
> And of course we could be happy to
> learn from your experience and share our
> (hopefully) future experiences with that method.
>
> Any hints and comments are highly welcome
>
> Anja
>
> ---------------------
> Dr. Anja Ischebeck
> Institut für Psychologie
> Universität Graz
>
> Universitätsplatz 2/DG, 8010 Graz
> Tel: +43 (0) 316 380-8503
> E-Mail: anja.ischebeck at uni-graz.at
> http://www.anps.uni-graz.at/anps
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-- 
Scott Makeig, Research Scientist and Director, Swartz Center for
Computational Neuroscience, Institute for Neural Computation, University of
California San Diego, La Jolla CA 92093-0961, http://sccn.ucsd.edu/~scott
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