Hi Steve,
thanks for your reply. My question refers to the command
'$FSLDIR/bin/cluster'. My impression is that it just puts out a cluster
list of (face, edge or vertex?) adjacent voxels, but the website states
that it uses GRF, which I am amazed of. Therefore, I was wondering
whether the output from e.g. 'cluster -i stat_vox_p_tstat<n> -t .95'
includes any kind of GRF based correction or if the website is
misleading here.
Cheers,
Niklas
Stephen Smith wrote:
> Hi - there's a little more info in the FEAT manual
> http://fsl.fmrib.ox.ac.uk/fsl/feat5/detail.html#poststats
>
> FEAT offers both voxel-based and cluster-based thresholding, in both
> cases the test statistic (voxel Z value and cluster size respectively)
> are turned into corrected p-values using GRF theory. Not sure if that
> answers your question - but hopefully it's a pointer in the right
> direction. For a lot more useful stuff on GRF see the Cambridge
> Imagers website.
>
> Cheers.
>
>
>
>
> On 16 Feb 2010, at 12:02, Niklas Stein wrote:
>
>> Hi experts,
>>
>> on the individual tools' documentation pages, for inference 'cluster' is
>> documented as 'cluster-based thresholding using GRF theory for
>> inference'. I was wondering, how (and why) GRF is incorporated into
>> 'cluster' and whether 'cluster' has any other purpose than giving a list
>> of clusters by thresholding output from randomise.
>> Please do not laugh at the potential sillyness of my question, but since
>> the documentation is sparse and it is listed as an inference tool I feel
>> in need for clarification.
>>
>> Cheers,
>> Niklas
>>
>>
>> --
>> Pflichtangaben gemäß Gesetz über elektronische Handelsregister und
>> Genossenschaftsregister sowie das Unternehmensregister (EHUG):
>>
>> Universitätsklinikum Hamburg-Eppendorf
>> Körperschaft des öffentlichen Rechts
>> Gerichtsstand: Hamburg
>>
>> Vorstandsmitglieder:
>> Prof. Dr. Jörg F. Debatin (Vorsitzender)
>> Dr. Alexander Kirstein
>> Prof. Dr. Dr. Uwe Koch-Gromus
>
>
> ---------------------------------------------------------------------------
> 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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Dipl.-Phys. Niklas Stein
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Institut für Systemische Neurowissenschaften
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Pflichtangaben gemäß Gesetz über elektronische Handelsregister und Genossenschaftsregister sowie das Unternehmensregister (EHUG):
Universitätsklinikum Hamburg-Eppendorf
Körperschaft des öffentlichen Rechts
Gerichtsstand: Hamburg
Vorstandsmitglieder:
Prof. Dr. Jörg F. Debatin (Vorsitzender)
Dr. Alexander Kirstein
Prof. Dr. Dr. Uwe Koch-Gromus
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