Dear Dorian
In this case, you could try to normalise the standard space maps into the single subject space (computing the transformation-parameters for the MNI single subject template and applying it to the VOI).
Best
Simon
> -----Ursprüngliche Nachricht-----
> Von: "Dorian P." <[log in to unmask]>
> Gesendet: 24.07.09 12:52:52
> An: <[log in to unmask]>
> Betreff: Re: [SPM] extract cluster in primary motor cortex
Hello all,
>
> Just to point out something (as this thread made me curious), the use
> of standard masks cannot work because Francesco doesn't want to
> normalize. In this case, probability maps of any kind would be
> useless. The only solution I thought of is manually creating a mask
> of the precentral gyrus for each subject.
>
> Best regards.
> Dorian
>
> 2009/7/24 Hammers, Alexander <[log in to unmask]>
>
> Dear Francesco,
>
> If I understand correctly, you’re after the intersection of an
> activation cluster with the primary motor area. Would it help if you
> simply masked your cluster with a mask of the precentral gyrus?
>
> In that case you could use a contemporary version of our maximum
> probability maps (e.g. Hammers A et al. Hum Brain Mapping 2003) which
> defines precentral gyrus in MNI/ICBM152 space based on manual
> delineations in 30 healthy controls, mapped into stereotaxic space
> and concatenated into unequivocal (maximum probability / mode) maps (
> freely available for academic use). Do email me if you’d like to try
> this.
>
> With best wishes,
>
> Alexander
>
> On 21/07/2009 15:12, "francesco de Bertoldi" <[log in to unmask]>
> wrote:
>
> Hallo!
>
> I've the activation map resulting from a single subject experiment
> with finger tapping task. The peak of activity I observe in the
> primary motor cortex usually extends to other areas (e.g., parietal
> areas), but I need to isolate and extract the portion of the cluster
> having the peak of activity in the primary motor cortex, using a
> threshold of p=0.05 uncorrected. Does anybody know a method to isolate
> and “cut” (and save as a .img) the portion of the cluster in the
> primary motor cortex?
> Normally, to do this, I use Marsbar and I know that it is possible to
> select subclusters from one single cluster. However, the problem is
> that it is not possible to precisely match the coordinates of my
> selected cluster with its spatial location on the activation map (that
> I do not want to normalize!) appearing on the glass brain.
>
> Thank you in advance
>
> Francesco
>
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--
===================================
Univ.-Prof. Dr. med. Simon B. Eickhoff
AG Neuropsychiatrische Systembiologie
Klinik für Psychiatrie und Psychotherapie
Universitätsklinikum Aachen
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und
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