The current stream actually does not run with fixation -- all the fmri data need to have wedge or ring stimulation. The design matrix is just a bunch of sines and cosines, nothing fancy.

Jeff Phillips wrote:

Hello all,

I am performing my first retinotopy analysis, and I'd like to get some more information about the model created by paradigm files in the retinotopy analysis. Specifically, I am unsure whether to include or exclude fixation periods from the ends of my retinotopy runs. I imagine the analysis must somehow take into account the slow drop-off of the BOLD response--can you tell me if/how it does so? Since the analysis asks for the number of cycles, but not the duration of each cycle, I worry that including extra timepoints will just result in FS concluding that my stimulation period is longer than it actually is. If there exists an example design matrix for the retinotopy analysis, that would also be useful.

Thanks,

Jeff Phillips University of Pittsburgh

---

---

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