DS_Simp.NoDelay
In this variation the time delay between the two LGN populations
in the standard DS_Simp model is removed by setting
tdelay in the LGN and LGN_D populations to be the same. In all
other respects, the two models are identical. This is to
demonstrate how disrupting the relative timing of inputs in a linear
DS model eliminates the stimulus dependence of correlation seen with
sinusoidal gratings.