Hi,

I prepare to run retinotopic mapping experiment. I need only polar angles, since I am interested in localization of V1,V2 and V3 only. So, on inflated brain I plan to locate regions' reversals (vertical and horizontal meridians). For the moment, I plan to use FreSurfer for only inflating the brain (fMRI data I analyze in SPM).

I have created two different stimuli and I would like to know:
1) Since I need only vertical and horizontal meridians is it OK to have only 90 degrees sector?
2) Since I need only vertical and horizontal meridians, how effective it would be instead of Fourier phase  analysis to make a GLM with a boxcar function?
3) Should my sector start straight at meridian line (as I did), or the sector should encompass it from both sides?
4) Is it optimal to make each sector block length about 10-12 secs

The stimuli:
http://www.youtube.com/watch?v=iW8sk44eyck
http://www.youtube.com/watch?v=DcGZW1pM-28

Thanks a lot for your help,
Vadim