The description of the procedure is in 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 normalized 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 regularization). 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.

The artifacts and contrast in our EPI images will differ from those in the
images that other scanners, sequences and subject orientations produce. The
ideal processing stream would involve having distortion corrected fMRI, for
which spatial normalisation parameters could be estimated from a rigidly
registered anatomical scan - preferably by matching its GM with a GM template
(or using the Segment button in SPM5).

Best regards,
-John

On Thursday 03 August 2006 22:30, Tracy Wang wrote:
> Hi Renat and all,
>
> We are currently running an aging study and potentially see problems
> when we start normalizing older adults using the MNI templates. Even after
> normalization, the older adult normalized brain still differ enough from
> the young adult normalized brain to be both visually identifiable and
> problematic when comparing across groups. Has anyone already created a
> solution to this problem? Or has anyone created a merged young-old
> template in MNI space using SPM to minimize this problem as of yet?
>
>
>
> On another note, I've also noticed that the EPI template seems to be
> curiously free of susceptibility artifact/dropout created from the nasal
> cavity. How was the EPI created as to minimize this dropout?
>
>
>
> Please advise.
>
>
>
> Best Regards,
>
> Tracy
>
>
>
> _____
>
> From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On
> Behalf Of Renat Yakupov
> Sent: Thursday, August 03, 2006 1:29 PM
> To: [log in to unmask]
> Subject: [SPM] creating new EPI template
>
>
>
> Hello SPM users,
>
>
>
> We have been having some problems with SPM normalization and we are
> thinking about creating our own EPI template.
>
> How can I do it? How is the one supplied with SPM2 created? We have about
> 100 subjects with 6 or more scans for each subject. Do I you all of them or
> do I select only a few? Thank you.
>
>
>
> Regards,
>
> Renat.