[Eeglablist] TMS artifact removal with constrained ICA

[Martin Wiener]

Hello,

Has anyone out there analyzed data in EEGLAB with a simultaneous
transcranial magnetic stimulation (TMS) and EEG paradigm?  There are a
number of methods out there that I've seen for removal of the artifact
generated by TMS, but I'm curious if anyone has implemented them
specifically in EEGLAB.  I'm currently analyzing data from a study I
conducted using TMS/EEG, but I've found EEGLAB to be less ideal for artifact
removal than other software alternatives; however, I prefer to use EEGLAB
for my analyses and so would like to get this to work.  The reason for
EEGLAB being less ideal is that running ICA doesn't sufficiently remove the
artifact; the amplitude of the TMS artifact is generally so large that it is
difficult to parse out TMS-induced artifacts from neural sources when
looking at the ICA components.  An alternative method that I've found is to
conduct a  temporally constrained ICA, wherein a subset of the continuous
data is marked as artifact and another subset is marked as clean; ICA can
then be conducted on both sets by maximizing components that are similar to
the artifact-marked dataset and minimizing components similar to the
clean-marked dataset, then applying a spatial filter to the continuous data.
 I've seen this technique written by Mark Pfleiger at Source Signal Imaging
and have used it to remove the TMS artifact in EMSE, but I'm wondering if
there is a way I can do this in EEGLAB, either with a plugin that conducts a
similar method or some other way.  Any help would be great, thanks!

-- 
Martin Wiener, M.S.
Doctoral Candidate in Psychology
Department of Psychology
University of Pennsylvania
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20110613/3f3509f5/attachment.html>