Do you have any suggestion where I can download the high resolution MNI
brain?
Erik
----- Original Message -----
From: "John Ashburner" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, September 17, 2001 12:08 PM
Subject: Re: how to get the brain surface in the manual
> > In the SPM99 manual, page 84, there are nicely rendered brains. I tried
to
> > create that kind of brain surface with the single_subj_T1.img in the
> > canonical folder. The following is what I did:
> >
> > 1. segment single_subj_T1.img (choose "NO" when prompted "Are they
> > spatially normalized?"; "Modality"-->"T1-MRI"; "No inhomogeneity
> > correction.") 2. select "Xbrain" in Display, choose
> > "single_subj_T1_seg1.img" and "single_subj_T1_seg2.img"
> >
> > However, the rendered brain does not look right (as shown in the
attached
> > figure). They are too smooth at some locations. The brain extraction
I've
> > done seems not producing the same effect as shown by the
> > render_single_subj.mat. Did I do anything wrong with segmentation or
brain
> > extraction? Or I missed some steps?
>
> You did all the right steps.
>
> The single subject dataset that render_single_subj.mat was based on had an
> isotropic resolution of 1mm. In order to reduce disk space downloading
time
> etc, I reduced the size of the dataset by a factor of 8 by reproducing
with
> voxels of 2mm. There is simply not enough detail in the downsampled data
> to derive a reasonable cortical surface.
>
> The renderings in the manual is derived from a high resolution dataset.
>
> Best regards,
> -John
>
> --
> Dr John Ashburner.
> Wellcome Department of Cognitive Neurology.
> 12 Queen Square, London WC1N 3BG, UK.
> tel: +44 (0)20 78337491 or +44 (0)20 78373611 x4381
> fax: +44 (0)20 78131420
> http://www.fil.ion.ucl.ac.uk/~john
> mail: [log in to unmask]
>
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