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<p class="MsoNormal">Dear Fieldtrippers,<o:p></o:p></p>
<p class="MsoNormal">I’m not sure whether my problem is a Fieldtrip or a Neuromag problem, but maybe someone can help me here.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve recorded MEG data with a Neuromag system and the headshape and hpi coils using the polhemus system. When I read the headshape and the sensor locations from the fif-file and plot them using Fieldtrip, the plots look as expected, i.e.,
the “headshape” and the hpi coils are located within the MEG sensors / helmet (see attached example figures S1_1 and S1_2 from different angles). For one subject, however, the sensors from the hdr.grad-file seem rotated and it even looks like the “headshape”
is partly outside the MEG sensors / helmet (see attached figures S2_1 and S2_2).<o:p></o:p></p>
<p class="MsoNormal">I have no idea what is going wrong here and/or how I could correct the apparently wrong positions. Any help would be much appreciated.<o:p></o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Jo<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Ps: the simple FT-code:<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">hdr = ft_read_header(‘subject.fif’);<o:p></o:p></p>
<p class="MsoNormal">headshape = ft_read_headshape(‘subject.fif’);<o:p></o:p></p>
<p class="MsoNormal">figure; <o:p></o:p></p>
<p class="MsoNormal">ft_plot_sens(hdr.grad, 'style', 'b.', 'coil', 'false'); <o:p>
</o:p></p>
<p class="MsoNormal">ft_plot_mesh(headshape.pos(1:4,:),'vertexsize',20,'vertexcolor','r'); %HPI coils<o:p></o:p></p>
<p class="MsoNormal">ft_plot_mesh(headshape.pos(5:end,:),'vertexsize',20,'vertexcolor','k'); %”manual” headshape<o:p></o:p></p>
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