Hi Nick I'm revisiting this issue and have a few more questions. First, I have a significant interaction between two variables on cortical volume. I drew a label on this ROI and ran mris_anatomical_stats on the label (thank you for that suggestion).
For stats in the output table file, is the column 'GrayVol' the same thing as the cortical volume I looked at in Qdec? I'm asking because when I export GrayVol values into SPSS, there is no longer a significant interaction between my variables (and if this ROI is significant after multiple comparisons across the brain, I'd expect the mean volume from the ROI to be very significant in SPSS). Please let me know if my questions aren't clear. 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 -----Original Message----- From: Nick Schmansky [mailto:ni...@nmr.mgh.harvard.edu] Sent: Thursday, January 13, 2011 3:08 PM To: Gallen, Courtney (NIH/NIDA) [F] Cc: Freesurfer Mailing List Subject: Re: [Freesurfer] Interpreting results from Qdec Courtney, if i understand your question, i think one way to do that is to use qdec to draw a label on the blob of interest, and the run 'map label to subjects', which creates a label file in each subjects label dir, then you can run stats on that with mris_anatomical_stats. (btw, i'm putting this answer on the list, as others may have better ideas.) n. On Mon, 2011-01-03 at 16:38 -0500, Gallen, Courtney (NIH/NIDA) [F] wrote: > Hi Nick > > Thanks for the prompt reply. Sorry if my questions seem a bit naïve--this is > my first time using Freesurfer. > > A follow up question to your answer for question 1. I see that the group data > will be plotted in Qdec for significant blobs, but say there is a significant > interaction between two variables and it's not entirely apparent what is > driving this interaction. > Is there a way to extract the mean of this blob for each individual (i.e., > treat it as an ROI or something similar) to determine what's driving the > significance? > > Thanks in advance! > Courtney > > -----Original Message----- > From: Nick Schmansky [mailto:ni...@nmr.mgh.harvard.edu] > Sent: Thursday, December 30, 2010 2:44 PM > To: Gallen, Courtney (NIH/NIDA) [F] > Cc: freesurfer@nmr.mgh.harvard.edu > Subject: Re: [Freesurfer] Interpreting results from Qdec > > 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 > > > > The information in this e-mail is intended only for the person to whom it is > addressed. If you believe this e-mail was sent to you in error and the e-mail > contains patient information, please contact the Partners Compliance HelpLine > at > http://www.partners.org/complianceline . If the e-mail was sent to you in > error > but does not contain patient information, please contact the sender and > properly > dispose of the e-mail. > > _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
