Hi Jörn,<br><br>Thanks a lot! Now it makes sense to me.<br><br>Best regards,<br><br>Qi<br><br><div class="gmail_quote">On Thu, Jan 5, 2012 at 3:20 AM, "Jörn M. Horschig" <span dir="ltr"><<a href="mailto:jm.horschig@donders.ru.nl">jm.horschig@donders.ru.nl</a>></span> wrote:<br>
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Dear Qi,<br>
<br>
Though I am not sure to what z-score formula you are referring to, I
guess you are talking about the 'summary' mode of ft_rejectvisual.
Z-scores are computed in different ways here, once across channels
and once across time, leading to two different plots. The third plot
is an accumulated plot of these two, where colors indicate the
strength of the selected measure (e.g. z-score). Thus, in terms of
the z-score formula, it is once computed with the average and
standard deviation across the time-dimension per channel and once
across the channel-dimension per time bin. I hope this clarifies why
the two plots don't show the same. <br>
<br>
ICA can also be applied to eye blinks, for which an example is given
in the "Walkthrough"<br>
<a href="http://fieldtrip.fcdonders.nl/walkthrough#using_ica_for_eye_artifact_removal" target="_blank">http://fieldtrip.fcdonders.nl/walkthrough#using_ica_for_eye_artifact_removal</a><br>
<br>
And of course, ICA can be used for anything else you believe in
(e.g. look for papers by Makeig)<br>
<br>
Best,<br>
Jörn<div><div class="h5"><br>
<br>
On 1/4/2012 4:52 PM, qi li wrote:
</div></div><blockquote type="cite"><div><div class="h5">Hi,<br>
<br>
I am confused about the plot of the z-score and 'most contribute'
channel trial plot in the automatic artifact rejection tutorial.
The z-score formula provided in the tutorial is linear to the
time course of a particular channel of a specific trial, but the
two plots don't look alike.<br>
<br>
ICA in the tutorial only applies to ECG, can it be applied to
remove eye blink and other known artifacts instead of rejecting
trials.<br>
<br>
Thanks!<br>
<br>
Qi<br>
<br>
<br>
<br>
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<pre cols="72">--
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands
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