Dear Guillaume,
thank you for your reply. This is already helpful for me, but I would have
a follow-up question on that.
After a GLM has been estimated, is it also feasible to just read the
values within an ROI of the RPV.nii image that is automatically saved? For
my understanding, this tells me the resels-per-voxel for all my voxels
within the ROI. Could I not simply add all the resels-per-voxel estimates
within the ROI to get the ROI resel count? However, I tried this and the
values I get seem to be roughly but not exactly the values that SPM prints
out when doing a small volume correction.
Would it nevertheless be feasible to take within-ROI values from RPV.nii
as a measure of smoothness of individual voxels and further derive the
number of resels within the ROI from RPV.nii?
Best,
Matthias
On 19/01/17 11:50, "Guillaume Flandin" <[log in to unmask]> wrote:
>Dear Matthias,
>
>Have a look at spm_VOI.m, the SPM function where "small volume
>correction" is implemented. It calls spm_resels.m that will return the
>Resel counts given a search space and the estimated smoothness (assuming
>stationarity).
>
>Best regards,
>Guillaume.
>
>
>On 19/01/17 08:47, Stangl, Matthias /DZNE wrote:
>> Hi all,
>>
>> I am currently looking for a way to correct the results of a statistical
>> test for spatial smoothness of the (fMRI) data. This should be done
>> outside SPM using custom Matlab code. However, I would need to calculate
>> the number of resels within an ROI for that purpose.
>> Is there any way (ideally an SPM function that I could call) which
>> calculates the number of resels within an ROI/volume in SPM?
>>
>> I would be very grateful if someone knows an easy way how to calculate
>> the number of resels or how to get to this value in SPM.
>>
>> Thank you,
>> Matthias
>>
>> --
>> Matthias Stangl
>> Aging & Cognition Research Group
>> German Center for Neurodegenerative Diseases (DZNE)
>> Leipziger Str. 44, 39120 Magdeburg, Germany
>> phone: +49-391-67-24520
>> email: [log in to unmask] <mailto:[log in to unmask]>
>> website: www.wolberslab.net
>>
>> --
>> Matthias Stangl
>> Aging & Cognition Research Group
>> German Center for Neurodegenerative Diseases (DZNE)
>> Leipziger Str. 44, 39120 Magdeburg, Germany
>> phone: +49-391-67-24520
>> email: [log in to unmask] <mailto:[log in to unmask]>
>> website: www.wolberslab.net
>
>--
>Guillaume Flandin, PhD
>Wellcome Trust Centre for Neuroimaging
>University College London
>12 Queen Square
>London WC1N 3BG
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