Mapping Results onto SUMA (Part 2)

In a previous post I outlined how to overlay results generated by SPM or FSL onto a SUMA surface and published a tutorial video on my Techsmith account. However, as I am consolidating all of my tutorials onto Youtube, this video has been uploaded to Youtube instead.

There are few differences between this tutorial and the previous one; however, it is worth reemphasizing that, as the results have been interpolated onto another surface, one should not perform statistical analyses on these surface maps - use them for visualization purposes only. The correct approach for surface-based analyses is to perform all of your preprocessing and statistics on the surface itself, a procedure which will later be discussed in greater detail.

A couple of other notes:

1) Use the '.' and ',' keys to toggle between views such as pial, white matter, and inflated surfaces. These buttons were not discussed in the video.

2) I recommend using SPM to generate cluster-corrected images before overlaying these onto SUMA. That way, you won't have to mess with the threshold slider in order to guess which t-value cutoff to use.

More AFNI to come in the near future!


I've posted a demo of AFNI's surface mapper program, SUMA, over here on my screencast account. Specifically, I talk about how to map volumetric results generated in any fMRI software package (e.g., AFNI, FSL, SPM, BrainVoyager) onto a template surface provided by SUMA.

In this demo, I take second-level results generated in SPM and map them onto a template MNI surface, the N27 brain. All that is needed for doing this is a results dataset, a template underlay anatomical brain to visualize results on (here I use the MNI_caez_N27 brain provided in the AFNI binaries directory under ~/abin), and a folder called suma_mni that contains the .spec files for mapping onto the N27 brain. The suma_mni folder is available for download at Ziad Saad's website here. Just download it to the same directory, and you are good to go.

SPM 2nd-level results mapped onto template surface using AFNI / SUMA

I've outlined the steps in a word document, Volumetric_SUMA.docx, which is available at my website. Please send me any feedback if any of the steps are unclear.

Although this is an incredibly easy way to make great-looking figures, at the same time I would not recommend doing any ROI stats on the results mapped onto a surface using these steps. This is because it is essentially a rough interpolation of which voxel corresponds to which node; if you want to do surface ROI analyses, do all of your preprocessing and statistics on the surface (I may write up a demo of how to do this soon).