Hi brainstorm forum,
I’m trying to conduct a between group analysis in SPM but have a problem with normalisation of the data into MNI space.
I’ve projected all my participants to the default anatomy using the ICBM template and can average the source data / conduct stats etc. The nifti images exported from BS (volumetric for SPM8 ) and subsequent t-maps however don’t overlap either with SPM’s single subject brain or the MNI ICBM152 template downloaded from the MNI website (see unintentionally funky image and the other, less funky but more informative image).
Any ideas where I might have gone wrong?
Thanks,
Peter
Never mind, turns out the ICBM template is slightly larger than the standard space used in SPM. Not sure about the other templates however.
Hi Peter,
The Colin27 and ICBM152 templates ares supposed to be registered to the same MNI stereotaxic space. One should not be bigger than the other.
What you are observing is most likely a registration problem. For some reason the origin of the MRI, ie. the coordinate (0,0,0), is not at the same place in the SPM reference volume and in the ICBM152 volume.
You can load the ICBM152 volume in SPM for your displays as you would do for the individual anatomy (illustrated in the tutorial).
If this doesn’t solve the issue, you can start by testing if it works correctly it you use the Colin27 brain to reconstruct the sources in Brainstorm.
Cheers,
Francois
Hi Francois,
Thanks very much for the advice. I'll export the ICBM152 MRI and see if that works.
EDIT
Yep, worked aok.
For anyone using SPM8 and wanting to present their data as a surface map, a similar effect can be had by exporting the template MRI volume, skull stripping (I used MRIcron) and viewing the template overlaid with the t-maps using mricroGL
