On the other hand, in almost a third of the sample (28.5%; 8/28 cells, all but one complex), inactivation of PTV resulted in increases in the magnitude of spike-responses to the optimized stimuli (Figures 2Di, 4A,B) and the increases were significant in ~10% (3/28, all complex) of the sample (Figure 2Di). In 2/19 cells in which effects of cooling on velocity preferences were tested, inactivation resulted in a clear enhancement of responses to stimuli moving at higher velocities (see Figure 2Dii, Preferred velocities). For a subset of cells tested for orientation-tuning, their peak responses are shown in Figure 2Diii. Note that only in one of those cells, there was a significant increase in peak firing rate during cooling (Figure 2Diii—A-npr).