Hi Michal,
At this point it is probably worth us taking a quick look at your
unthresholded zstat (...feat/stats/zstat1) image to get a feeling for
what the data looks like.
If you'd like to sent it, please upload the files in a single
compressed tarfile to
http://www.fmrib.ox.ac.uk/cgi-bin/upload.cgi
and then email me the upload ID.
Cheers, Steve.
On 25 Apr 2006, at 13:37, Michal Kuniecki wrote:
> Dear Christian,
>
> Thanks again for an answer, now at least I know what you mean by
> sensible
> histogram. It seems however that your answer assumes that the
> situation I am
> describing must result from some kind of error. I am not that sure
> about it.
> I have got 40 subjects in the analisys, in simple visual blocked
> design so I
> guess when simple effects are considered one would expect largely
> significant results.
> Anyway lets assume for a while that my results are OK, and lets
> reiterate
> my original question, namely how can you avoid getting one cluster
> spanning
> through entire brain? Or how can you avoid getting cluster covering
> two
> distinct brain structures. Quite often you get one cluster when two
> big
> patches of activity are "connected" by a narrow lets say bridge of
> active
> voxels. Is there any way of separating them? In other words is
> there any
> utility available to manipulate the span of clusters? Any measure of
> closeness ? I tried the cluster command but without much success. I
> thought
> that maybe the --connectivity switch governs the span of the
> cluster but it
> proved wrong (changes to connectivity value did not affect the span
> of the
> clusters at all). There must be some algorithm that decides where one
> cluster ends and another one begins. Is there any way of
> controlling how
> this algorithm works?
>
> Best regards
> Mike
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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