Andreas
Doh! Yes the units of design was set incorrectly - that seems to have fixed the missing events and the correlations issues. Thanks
Just out of interest, why do you suggest turning off Global Normalisation?
Thanks
Rob
-----Original Message-----
From: Andreas Finkelmeyer [mailto:[log in to unmask]]
Sent: 28 July 2015 10:06
To: Robert Hoskin; [log in to unmask]
Subject: RE: [SPM] Help troubleshooting missing events in design matrix
Hi Rob,
Do your "units of design" match the actual onset times? If not, e.g. if you specified onset times in seconds, but units of design is set to "scans", it's possible that events dropped off the end of a session.
Cheers,
Andreas
PS: I suspect you probably also want to turn off "global normalization", though I don't think that has anything to do with your onset issue.
===================================================
Andreas Finkelmeyer, Ph.D.
Academic Psychiatry, Institute of Neuroscience Wolfson Research Centre, Campus for Ageing and Vitality Newcastle University Newcastle upon Tyne
NE4 5PL, UK
Tel.: +44 (0)191 208 1357
Web: www.ncl.ac.uk/ion
>-----Original Message-----
>From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On
>Behalf Of Robert Hoskin
>Sent: 27 July 2015 17:32
>To: [log in to unmask]
>Subject: [SPM] Help troubleshooting missing events in design matrix
>
>Hi
>I have an event related design with a cue>outcome design. There are 4 cues
>and 8 potential outcomes, with the timing between cue and outcome jittered.
>The task has 4 blocks of 60 trials each. There should be 15 events in each block
>relating to each cue. The outcomes each have either 10 or 5 events per block
>(making a total of 60 outcomes per block).
>
>I've entered the onset times into the first level analysis, but the resulting design
>matrix doesn't appear to have modelled all the events - such that some
>conditions only have 2 or 3 events per block. Furthermore for two of the
>conditions in the final block, SPM doesn't seem to be able to find any events at
>all, and thus registers them as being correlated (see attached .bmp). If I look
>into the SPM.xX.X matrix this is confirmed, as all the values for these conditions
>have a value of 0.
>
>I've checked the SPM.Sess structure and the onset times appear to have
>loaded OK. Does anyone have any ideas why SPM has not been able to model
>each event? Or does anyone know how I can troubleshoot this problem
>further?
>
>Thanks
>Rob
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