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<div class="moz-cite-prefix">Hi Kidist,<br>
<br>
<br>
On 10/16/2013 3:30 PM, <a class="moz-txt-link-abbreviated" href="mailto:kgm@tf.uni-kiel.de">kgm@tf.uni-kiel.de</a> wrote:<br>
</div>
<blockquote
cite="mid:dd60122e6f2331f51a8bfb81ed8e9ce7.squirrel@webmail.tf.uni-kiel.de"
type="cite">
<pre wrap="">Hello,
I am trying to do forward modeling using individual MRI and MEG from
Neuromag306 system. I have three questions.
I have performed the following steps:
1. ft_read_mri
2. ft_volumerealign
3. ft_volumesegment
Q1. At this point I want to check if the segmentation fits the MRI
correctly. So I used ft_sourceplot but I am getting the following
message with an empty plot:
the input is segmented volume data with dimensions [256 256 176]
scaling anatomy to [0 1]
no functional parameter
no masking parameter
the call to "ft_sourceplot" took 4 seconds</pre>
</blockquote>
<br>
Hard to tell, maybe post a snippet of your cfg? First, however, you
might want to have a look at this tutorial and especially check how
the segmented mri is plotted and what else is done:<br>
<a class="moz-txt-link-freetext" href="http://fieldtrip.fcdonders.nl/tutorial/beamformingextended#preparing_the_data_and_the_forward_and_inverse_model">http://fieldtrip.fcdonders.nl/tutorial/beamformingextended#preparing_the_data_and_the_forward_and_inverse_model</a><br>
<br>
<blockquote
cite="mid:dd60122e6f2331f51a8bfb81ed8e9ce7.squirrel@webmail.tf.uni-kiel.de"
type="cite">
<pre wrap="">4. ft_prepare_headmodel, method: singleshell
5. ft_plot_sens and ft_plot_vol, after converting the units
Q2. The plot shows that the sensors/electrodes are quiet far away from
the brain. Is there a means to do some projection to lower them a bit?
Or is the problem arising from the co-registration? I have attached the
figure.</pre>
</blockquote>
Most likely, this is indeed a problem with the co-registration, or
the subject was just seated that way. You mustn't just project
sensors to make the plot appeal better to you ;) <br>
<br>
<blockquote
cite="mid:dd60122e6f2331f51a8bfb81ed8e9ce7.squirrel@webmail.tf.uni-kiel.de"
type="cite">
<pre wrap=""> Q3. I have also used 'localspheres' method to prepare the head model.
The output of the plot (attached) gives me some rounded image which
does not look like a brain. Is there another function used to plot the
local spheres?</pre>
</blockquote>
My guess is that you need to reduce the radii of the localspheres.
Looks like they are defined in cm while the rest of your anatomy is
defined in mm. <br>
<br>
<br>
Best,<br>
Jörn<br>
<br>
<blockquote
cite="mid:dd60122e6f2331f51a8bfb81ed8e9ce7.squirrel@webmail.tf.uni-kiel.de"
type="cite">
<pre wrap="">
Looking forward for the response.
Best regards,
Ms.c. Kidist G.Mideksa
Department of Neurology,
Uni-Klinikum, Kiel, Germany
</pre>
<br>
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<br>
<pre wrap="">_______________________________________________
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<a class="moz-txt-link-freetext" href="http://mailman.science.ru.nl/mailman/listinfo/fieldtrip">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a></pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
FieldTrip Development Team
P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands
Contact:
E-Mail: <a class="moz-txt-link-abbreviated" href="mailto:jm.horschig@donders.ru.nl">jm.horschig@donders.ru.nl</a>
Tel: +31-(0)24-36-68493
Web: <a class="moz-txt-link-freetext" href="http://www.ru.nl/donders">http://www.ru.nl/donders</a>
Visiting address:
Trigon, room 2.30
Kapittelweg 29
NL-6525 EN Nijmegen
The Netherlands</pre>
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