Thanks for the answer!
Quoting [log in to unmask]:
> SPM corrects for sphereicity in the data, using a sub-set of voxels
> which have a significant main effect based, if I recall correctly,
> an f-test run internally during the 1st level analysis.
>
> The error is that there are no such voxels to test sphereicity
> against. This also implies a problem either with the model or the
> data. By problem, it could mean the data is not good, the model has
> an error and does not properly match the data (e.g. the event
> timings are wrong), or you may have run an experiment which just
> does not really evoke a BOLD change.
>
> Every time I have seen this error in my on work, it has been a
> harbinger of problems and a total lack of effect. For example, in
> one instance, we had noisy data, and I believe we
> 'over-preprocessed' it, so there was not enough signal variance
> related to the task for form a decent model.
>
> You can in principle reduce the statistical threshold to try to get
> around this. I am not sure I would recommend this. However in
> spm_defaults, it is defaults.stats.fmri.ufp
>
> Good luck,
>
> Colin Hawco, PhD
> Neuranalysis Consulting
> Neuroimaging analysis and consultation
> www.neuranalysis.com
> [log in to unmask]
>
>
>
>
> -----Original Message-----
> From: SPM (Statistical Parametric Mapping)
> [mailto:[log in to unmask]] On Behalf Of Kari Lehikoinen
> Sent: September-20-16 12:48 PM
> To: [log in to unmask]
> Subject: [SPM] Problem with 1st level analysis in SPM; "no
> significant voxels"
>
>
> Hello everyone
>
>
> I've been trying to do 1st level analysis in SPM, and keep running
> into a "no significant voxels" -error. There is also another error
> message before that, which I've attached to this message.
>
> I have several subjects and several conditions, and this problem
> only happens for some of the subjects, and only in one condition,
> despite my batch scripts being similar (also attached).
>
>
> So, I guess my question is: is this real error message, or do those
> cases really just not have significant voxels? I've searched the
> archives, and although this error message seems common, I haven't
> found a situation that matches mine.
>
>
> Thanks for anyone who can help.
>
> - Kari Lehikoinen, University of Helsinki
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