Parameters used to build each set of motion stimuli. For the gratings, the temporal frequency tf is modulated to obtain the same speed at every spatial frequency sf. Motion Clouds do not have a tf parameter, they are controlled directly by the speed parameter V. Spatial frequency bandwidths Bsf Narrow and Bsf Broad are parametrized to obtain non-overlapping and overlapping  envelopes respectively (see   for details) Note that the software works in pixel units, so a proper scaling has to be applied. In our case, the conversion factor between pixels an mm is 240:1.