Dear Francesco
Alternatively, if you are more specifically interested in the primary motor cortex, rather than the precentral gyrus (which is mainly covered by premotor cortex), you could use the SPM Anatomy Toiolbox.
This atlas is based on the histological delineation of cortical areas in human post-mortem brains, which have subsequently been normalised into MNI space. It offers probabilistic maps for these areas (including the primary motor cortex) as well as the corresponding maximum probability maps and an VOI tool.
Hope this helps
Simon
> -----Ursprüngliche Nachricht-----
> Von: "Hammers, Alexander" <[log in to unmask]>
> Gesendet: 24.07.09 11:46:09
> An: <[log in to unmask]>
> Betreff: Re: [SPM] extract cluster in primary motor cortex
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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