Dear Emilia,
As Colin mentions, an image of how your results look like would help.
I would guess this can be explained by the presence of regions with very
low variance as described in this article:
https://www.ncbi.nlm.nih.gov/pubmed/22037420
If SPM GLM estimation is running with the defaults for fMRI the residual
mean squares are modified according to the article above to remove this
effect.
Best regards,
Guillaume.
On 23/01/17 20:32, Colin Hawco wrote:
> Check your normalizations. Overlay some scans on the MNI template or
> whatever you used as your target for normalization.
>
>
>
> Also how far outside the glass brain? A little bit around the edge or a
> lot? The glass brain is not definitively registered to your data, it is
> more of a guide based (I assume) off voxel coordinates. Depending on
> what template you registered to, your data may not be a perfect fit for
> the glass brain which is presumably based on the MNI template.
>
>
>
> A pic of your results in the glass brain might help. But start with your
> subject scans, and see if they overlay the MNI template.
>
>
>
> best of luck,
>
>
>
> Colin Hawco, PhD
>
> Neuranalysis Consulting
>
> Neuroimaging analysis and consultation
>
> www.neuranalysis.com <http://www.neuranalysis.com>
>
> [log in to unmask]
>
>
>
>
>
>
>
>
>
> *From:*SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]]
> *On Behalf Of *Emilia Cheladze
> *Sent:* January-23-17 2:28 PM
> *To:* [log in to unmask]
> *Subject:* [SPM] activation outside the brain
>
>
>
> Dear SPM experts,
>
> we're doing a resting state analysis in spm using the dparsfa toolbox
> and for some reason we're getting activation outside the glass brain
> when we look at the results.What are possible causes for that? Where
> should I look in order to identify the problem? Any help identifying
> what could be going wrong would be greatly appreciated!!
>
> Thank you in advance for help,
>
> Emilia Cheladze
>
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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