just to chime in: they would not necessarily be worthless as you could
determine a "individual to MNI" mapping and apply the inverse,
conveniently saved by unified segmentation, to the standard mask. Not
necessarily very elegant, but hey ;)
Dorian P. schrieb:
> 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.
> 2009/7/24 Hammers, Alexander <[log in to unmask]
> <mailto:[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,
> On 21/07/2009 15:12, "francesco de Bertoldi" <[log in to unmask]
> <[log in to unmask]" target="_blank">http:[log in to unmask]>> wrote:
> 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
> 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
> I do not want to normalize!) appearing on the glass brain.
> Thank you in advance
Marko Wilke (Dr.med./M.D.)
[log in to unmask]
Universitäts-Kinderklinik University Children's Hospital
Abt. III (Neuropädiatrie) Dept. III (Pediatric neurology)
Hoppe-Seyler-Str. 1, D - 72076 Tübingen
Tel.: (+49) 07071 29-83416 Fax: (+49) 07071 29-5473