ans. 1. - the easiest way is to Ctrl- left mouse click on a blob, and a plot of the data at that surface vertex will appear. the group will be apparent from that (say, demented group is thinner than non-demented group). this data is significance data (log p, so '2' is 0.01), so mean and stdev wouldnt apply in that case. the file 'y.mgh' is the raw data of all subjects in the analysis, so you could extract mean and stdev from that.

ans. 2. - slide the 'annotation' opacity slider to show the annotation data (cortical parcellation). the ctrl left click will also put the region info for that vertex on the lower left of the display.

see also: http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/QdecGroupAnalysis

n.

On Wed, 2010-12-29 at 10:49 -0500, Gallen, Courtney (NIH/NIDA) [F] wrote:

Hi,

I’m currently running analyses in Qdec and have identified areas that show significant effects in my contrasts. I have two questions related to interpreting these results.

1. How can you interpret the effect in each “blob?” (i.e., which
   

group has a greater cortical surface area, etc.). Right now, all I know is that there is an effect in certain areas. Can you export this data to get means and standard errors?

2. Is there a way to localize where these effects are? E.g., a
   

tool that tells you this effect is located in __ area of the brain?

Thanks in advance

Courtney

Courtney Gallen

Post-baccalaureate IRTA

Neuroimaging Research Branch

National Institute on Drug Abuse (IRP)

251 Bayview Blvd

Suite 200

Baltimore, MD 21224

Tel: (443) 740-2631

---

Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer