Your missing a line of code, the code should be:
Vhdr=spm_vol('con_0001.img');
V=spm_read_vols(Vhdr);
XYZ(:,1)=[-26, 0, -18];
beta=spm_get_data(V,XYZ)
This will give you a single point value for the contrast value of contrast 1
at the specified location. If you want the beta values, then you need to
load the beta images. If this is a second level model and you are wanting
the input image values, then you need to load the input image values. In
this case, you will want to look at my VOI tool (see previous posts /
www.martinos.org/~mclaren/ftp/Utilities_DGM/ and download All*tar).
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Office: (773) 406-2464
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On Fri, Aug 12, 2011 at 9:17 AM, Daehyun Jung <[log in to unmask]>wrote:
> Dear SPMers,
>
> I've used marsbar to extract beta values.
>
> The problem is that I cannot extract beta value from con_0001.img.
>
> Marsbar only allow to read SPM.mat. So I cannot read the com image
> directly.
>
> Is there any way to extract beta value by reading the con image?
>
> I have tried to use
>
> V=spm_vol('con_0001.img')
> XYZ(:,1)=[-26, 0, -18]
> beta=spm_get_data(V,XYZ)
>
>
> I got "zero" beta value.
>
>
> Best regards,
>
>
