Dear SPM community
I am having troubing analyzing fMRI data generated by a particular visual
stimulus and would appreciate any tips people may have.
The stimulus consists of a wedge with its point centered on the origin. The
wedge continuously rotates around the origin, completing a revolution every
I am interested in analyzing the BOLD signals from V1 (the primary visual
cortex) using SP5. Because V1 is topographically organized the region of
activity caused by the wedge should slowly move across the surface of V1. I
would like to show this movement. I think that the easiest way to do this
would be to fit a peridodic funciton (e.g. a sin wave) to the activity at
each voxel in V1 and then plot a map of the phase at each voxel. This phase
should change in a gradual manner and so illustrate the topography of V1.
My question: How can I fit a cyclical function to the bold signal at each
voxel, extract the phase for each voxel, and then plot these phases on a map
of the brain?
Many thanks for any help you may be able to give.
Piers Howe, PhD
Harvard Medical School
Boston, MA 02115, USA