Hi
I had exactly same problem. I'm sorry I didn't get the point from your
discussion. So what's the solution? Thanks.
Qingyan
>From: Stephen Smith <[log in to unmask]>
>Reply-To: FSL - FMRIB's Software Library <[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: [FSL] report.html missing activation image
>Date: Thu, 23 Aug 2001 18:54:53 +0100
>
>Hi.
>
> > I looked at zstat.img and indeed the values were very low. I did find
>some
> > spurious voxels with Z's larger than 2.3, (for example, the one
>report.html
> > shows a time plot for (Z=4)).
>
>Some voxels have passed the first part of the cluster-based thresholding
>(eg above >2.3) but then the resulting clusters fail the probability test
>(eg is P<0.01) because they are not large enough. If you had chosen
>resel-based thresholding instead of cluster-based you may have found a
>little activation, but in this case the required Z threshold (derived from
>the voxel-level P which you set) will be greater than 2.3 probably.
>
> > Certainly the experiment is no good. But, just out of curiosity, why
>were
> > these voxels not pointed out, even when FEAT is set to no thresholding?
>
>you get the time plot for max Z but no colour overlay because no clusters
>survived thresholding and no average timecourse for the same reason.
>
>when FEAT is set to no thresholding that automatically carries through to
>no colour overlay because no "activation" has been defined.
>
>Thanks, Steve.
QingYan [log in to unmask]
(425)391-8251
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