Direction modulation of a sinusoidal grating. During each 10 ms
epoch, the stimulus travels in either the preferred or antipreferred
direction, chosen according to a pseudo-random m-sequence. The
displacement step is constant, only the direction changes. This
stimulus can be used to compute spike-triggered averages that reflect
the window of temporal integration of direction selective neurons.
This is a series of 9 stimuli in which the speed of motion, quantified
by the effective temporal frequency (ETF), is varied.