[FieldTrip] problem with leadfield

[philip Joadavi]

Dear all,

I'm trying to compute the leadfield for my EEG data.
I've done all the steps in the tutorial, here
<https://www.fieldtriptoolbox.org/workshop/oslo2019/forward_modeling/>.
I run the *bemcp*, for computing the headmodel. Since in my data I have 2
electrode sets (64 channels and 32 channels), I tried to compute the
leadfield for 64 and then extract the leadfield from that file for 32
channels. However, when I compute the leadfield for 32 channels *separately*,
the results are different from when I *extract *the 32 channels from the 64
channel leadfield.

I have checked everything, the patterns that I get are exactly the same,
but the values from the leadfield computed separately from 32 channels are
higher when I plot the potentials (using the simulation in the tutorial).
Can someone explain why is this the case and where it happens in the code
for computing the leadfield? why the number of channels is important for
leadfield computation?

Unfortunately, I can not run the 'simbio' to compare.

Thank you very much!
Best,
Philip
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20210411/d7beb49d/attachment.htm>