If you have one subject, then there is no need to run a two stage model. Instead, create a design matrix or FSGD for that one subject. Eg, create the FSGD with one class. Create one Variable called TimePoint. Create an Input line for each time point indicating the class and the time point number as the variable (remove the mean of the time points from the time point number number). Then create a contrast with 0 1. When you run mri_glmfit, it will test the slope of the thickness-time effect (I'm assuming that is what you want).
On 4/17/2025 5:37 PM, Isabella Rossellini wrote: > External Email - Use Caution > > Dear Douglas, > > I am sorry for the late response. I did not see your message up until now. > I would like to see how the brain changes for a patient with anxiety > who got better gradually (again, we have 5-time points (0, 3, 6, 9, > 12). And then do the same for another participant who did not get > better up until 12 months. > That is the reason I would like to look at patients one by one. > > I ran the mri_glmfit analysis but I received an error message: > > ERROR: DOF=0 > > Is this because I tried to run it on one participant? > > Sincerely, > Isa Rosselini > > Date: Mon, 3 Feb 2025 09:20:40 -0500 > From: "Douglas N. Greve" <dgr...@mgh.harvard.edu> > Subject: Re: [Freesurfer] longitudinal analysis on one subject > To: freesurfer@nmr.mgh.harvard.edu > Message-ID: <ebc3545a-9335-4b43-b7ae-da3c0b1d0...@mgh.harvard.edu> > Content-Type: text/plain; charset="utf-8" > > The glm can be run on this data in theory. With only 5 time points, you > probably won't have much power though. What are you trying to test? > > On Sat, Feb 1, 2025 at 11:56 PM Isabella Rossellini > <irossellin...@gmail.com> wrote: >> Hello Freesurfer users/experts, >> >> I am working with Freesurfer 7.4.1 on a MacStudio (macOS 15.2) and I would >> like to ask your opinion about the following. >> >> Basically, we had an anxiety treatment study and I would like to analyze one >> subject who has 5-time points (0, 3, 6, 9, 12) with a longitudinal pipeline, >> two-stage model. >> Is it possible to run this on one person only and see the changes between >> these time points? >> >> I have never done this before on one subject so I am not sure what the best >> approach would be to look at the changes. >> After running the longitudinal preprocessing (base, long), should I generate >> the tables of freesurfer parcellation/segmentation stats data >> (aparcstats2table, asegstats2table)? >> Or can I just follow the two stage model steps? Maybe glm only works on a >> group of subjects. >> https://secure-web.cisco.com/1RCkpkv-7j7POY3iFHgRmXEUWgfCzKlqbBUGWLnc2RlZdY5nRKqE-Tyb58jPc7L5ZPOCj6Wk4FkzBnwiIVrHsBykQRm-l3Jn-ZMspfbCqLAWIrq78XF02rbouW2bUaQWQNyt7YSwswKJilktqReJF5U1Df5Vr3t2cMRnUzqQLCxsS8m1HXvZ131aAEwaFpFcRjH7wSODHJcqJ6YZa9avlKQ_jV6v0vzL-YLQKMIh0TQ8l5U9AvXEtxA3wt-JqnjnWCnYOTs0hem1ZdTHwx61ND4OhpBsVvE3WulFdmyCEXSNxDeIjuj_Ox30tQ-CZXxiEPu7qmKWNnFc710luNzkSnQ/https%3A%2F%2Fsurfer.nmr.mgh.harvard.edu%2Ffswiki%2FLongitudinalTwoStageModel >> >> (We have 9 more subjects - 10 in total - so I was hoping to visualize the >> pattern of changes one by one, in each subject, since these patients showed >> different changes in anxiety based on self-reported >> questionnaires) >> >> Sincerely, >> Isa Rosselini >> > _______________________________________________ > 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 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 Mass General Brigham Compliance HelpLine at https://www.massgeneralbrigham.org/complianceline <https://www.massgeneralbrigham.org/complianceline> . Please note that this e-mail is not secure (encrypted). If you do not wish to continue communication over unencrypted e-mail, please notify the sender of this message immediately. Continuing to send or respond to e-mail after receiving this message means you understand and accept this risk and wish to continue to communicate over unencrypted e-mail.
