help > Problem comparing Results in SPM vs. Conn
Jul 1, 2014  12:07 PM | Julia Landsiedel - University of Kent
Problem comparing Results in SPM vs. Conn
Dear all,

I encountered the following issue using the conn and SPM display. I used the exact same p-values and extent thresholds but surprisingly SPM outputs different MNI coordinates for the peak voxels (in a seed to voxel analysis) compared to conn. The coordinates are mostly just slightly shifted. How could that be? Did anybody encounter the same problem? Related to this comparing the surface display in conn and the render in SPM there are some activations not displayed in the conn display. Any idea for this? (see attached some screenshots for both problems)

Also I was wondering whether it could be possible to add to the toolbox functions that one also can be able to enter exact T-Values in the conn-display as height threshold. I also realized that using p-values so small that they extend a T-value of 10 makes all connectivity disappear in the conn display whereas in SPM it works fine. Also when going back to a higher p-value in the conn display afterwards gives the following warning:
Warning: Returning NaN for out of range arguments
> In spm_Pcdf at 90
In spm_P_RF at 110
In spm_P at 47
In conn_vproject>vproject_display at 737
In conn_vproject at 413

Thanks a lot!

Best,
Julia
Attachment: screenshots.pdf

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TitleAuthorDate
Problem comparing Results in SPM vs. Conn
Julia Landsiedel Jul 1, 2014
Alfonso Nieto-Castanon Jul 1, 2014
Alfonso Nieto-Castanon Jul 2, 2014
Julia Landsiedel Jul 3, 2014