Dear Jun,
For precision of source localisation it wouldn't make any difference.
The possible reasons to do it can be as follows:
1) Some structural scans are at much higher resolution than necessary
to make a head model. As a result head model generation runs slowly.
Reslicing to the template resolution takes care of that.
2) Sometimes the code can fail if the individual image is grossly
misaligned with the template.Doing the coregistration first (and
sometimes you also need to do rough manual alignment as well before
that) guarantees that this will not happen.
3) There is an option to write out the results in Native space (in the
batch version of source reconstruction). You might want this native
space to be aligned to the template space rather than shifted.
Best,
Vladimir
On Thu, Sep 13, 2012 at 3:17 PM, Jun Wang <[log in to unmask]> wrote:
> Thanks, Vladimir. Would you recommend doing Coregister
> (Est&Reslice) for getting better source modelling results? The "Multi-modal
> faces" sample didn't do that.
>
> best
> Jun
>
>
> On Thu, Sep 13, 2012 at 5:03 AM, Vladimir Litvak <[log in to unmask]>
> wrote:
>>
>> Dear Jun,
>>
>> No, this is not a problem. It looks like the meshes fit the structural
>> well (the direction of the slices doesn't matter). If you want a
>> better correspondence with the template image you can do Coregister
>> (Est&Reslice) in the fMRI part of SPM using your individual image as
>> input and the template as the target. You can then use the output of
>> that for you source modelling and it should correspond to the template
>> much better (although the head size will still differ).
>>
>> Best,
>>
>> Vladimir
>>
>> On Thu, Sep 13, 2012 at 1:41 AM, Jun Wang <[log in to unmask]> wrote:
>> > Dear SPM experts,
>> >
>> >
>> >
>> > As a SPM beginner, I am analyzing my subjects by following the
>> > "Multi-modal
>> > faces" sample dataset. I had some troubles with EEG co-registration.
>> > After
>> > loading individual subjct's T1 image, the EEG mesh(F1) I got looked
>> > weird
>> > and doesn't look like the one shown in manual. The sagittal slices not
>> > the
>> > transverse slices were presented with mesh. I am not sure why this
>> > happens,
>> > Maybe someone can help. Also, when I checked the registration by
>> > comparing
>> > my image with SPM template, the crosshair doesn't show in the same areas
>> > of
>> > two images(F2). Is that means my subject's MRI image needs to be
>> > modified?
>> >
>> >
>> >
>> > Thank you in advance,
>> >
>> >
>> >
>> > Best wishes,
>> >
>> > Jun
>
>
|