It was made a while ago. Here is all that was written about the
procedure (from spm_templates.man).
% templates/EPI.nii
% -------------
% The image was created from the average of 13 subjects mean fMRI
% images. The grey matter was segmented from the original images
% using the segmentation in SPM. This was spatially normalised by
% matching to the apriori/grey.nii file using a 12-parameter
% affine registration, followed by a nonlinear registration
% (using the 7x8x7 lowest frequency DCT coefficients, and
% heavy regularisation). These estimated parameters were
% then applied to the functional images, which were then averaged
% and smoothed with an 8mm FWHM Gaussian kernel. The EPI images
% were acquired on a Siemens Vision scanner working at 2T. The
% original resolution of the images was an isotropic 3mm (1.8mm
% slice thickness + 1.2mm gap). A gradient echo sequence was
% used with TE@ms and a TR of about 3s. Inter echo spacing is 800
% micro seconds with a sinusoidal gradient waveform and
% nonlinear ADC sampling. Nyquist ghost suppression is achieved
% using a 2 echo reference scan (only 0th and 1st order phase
% correction implemented). Maximum gradient strength is approx.
% 20mT/m.
% Subject numbers: 1285 1286 1287 1291 1314 1379 1381 1399 1479
% 1514 1589 1644 1646.
Best regards,
-John
On 10 March 2012 17:44, Glen Lee <[log in to unmask]> wrote:
> Dear John,
> Thanks for the helpful answers and clarifying my confusion about the ICBM
> file.
> Just one more quick question and hope you don't mind answering it:
> Can you explain how the EPI template was generated in the current SPM8
> version?
> -Glen
>
>
> On Fri, Mar 9, 2012 at 9:05 AM, John Ashburner <[log in to unmask]> wrote:
>>
>> > I'm about to normalize 10 individual subjects' Beta maps onto the MNI
>> > standard template (/template/EPI.nii) and want to make sure that I'm
>> > doing
>> > it correctly.
>> > So, I always use the mean image (that is generated after registration)
>> > as
>> > the source image when I normalize the bold images. And now, I'm
>> > wondering if
>> > I can use the same mean image for normalizing Beta maps as well?
>>
>> The same spatial transform should be applicable to all data that is in
>> alignment with the image that you estimate the transform from. In
>> your case, the beta maps should be perfectly aligned with the mean
>> from the realignment, so the transform should be applicable.
>>
>>
>> > Also, as a side note, can anybody confirm that SPM8 still uses the
>> > MNI152
>> > template for its template? In other words, /template/EPI.nii is the ICBM
>> > 152
>> > template, correct?
>>
>> The EPI.nii file is not actually an ICBM file. It was one that I
>> generated from a relatively small number of subjects scanned in the
>> FIL, using some quite old SPM functions (maybe SPM99, but I don't
>> remember now). It should be in approximate alignment with the ICBM
>> 152 data though.
>>
>> Best regards,
>> -John
>
>
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