The cluster-level significance values are contained in the “cluster-level” section of the table and indicate the p-value associated with finding a cluster of the given size (for several correction methods). The “peak-level” results are voxel-level p-values/T-scores. Each cluster will report 1 or more peaks, with the first always being the overall highest valued voxel in that cluster, and sometimes others being present which represent peaks that are more than 8mm apart from each other (as indicated by the text at the bottom of the table) and it will only show the 3 highest such peaks.
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Mike Angstadt
Research Computer Specialist / PANLab Lab Manager
Department of Psychiatry / University of Michigan
(734) 936-8229
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of Joelle Zimmermann
Sent: Tuesday, April 12, 2016 4:08 PM
To: [log in to unmask]
Subject: Re: [SPM] reporting results
Hi Colin,
I don't actually see a single peak t-value in the results. Could you clarify a bit? I'm attaching my results table here for reference. The cluster level significance that you mention would be reported are basically just the T-values in the peak-level section of the table, I think.
Thanks,
Joelle
On Mon, Apr 11, 2016 at 9:37 PM, <[log in to unmask]> wrote:
Oh sorry I meant to be specific. Often the peak t-value is reported. Occasionally a cluster level significance is included as well.
From: Joelle Zimmermann [mailto:[log in to unmask]]
Sent: April-11-16 8:53 PM
To: [log in to unmask]
Cc: [log in to unmask]
Subject: Re: [SPM] reporting results
Hi Colin,
Thanks for your help. The table you refer to is the results table where the cluster and peak level results are reported with T-value, Z-values, and coordinates for each, right? So there is not one single t-value that should be reported for the whole analysis?
Thanks,
Joelle
On Mon, Apr 11, 2016 at 8:36 PM, <[log in to unmask]> wrote:
Open results and hit whole brain. That produces a table which can be used modified as people typically do in figures.
Reporting first level contrasts is usually only done in very specific situations but will generally be done the same as most group analyses.
T=2.69 is a statistical threshold which depends on your uncorrected p-value.
Best of luck.
Colin Hawco, PhD
Neuranalysis Consulting
Neuroimaging analysis and consultation
www.neuranalysis.com
[log in to unmask]
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of Joelle Zimmermann
Sent: April-11-16 8:04 PM
To: [log in to unmask]
Subject: [SPM] reporting results
Hi SPMers,
I was wondering how SPM stats from for example a standard fmri second level analysis with an 'average' contrast (one sample t-test) is typically reported. From my understanding, the t-value that is reported is always the same, t=2.69.
Thanks,
Joelle
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