(A) Effects of PTV cooling on PSTHs of spike-responses of a class 2 area 17 complex cell to optimally oriented light bar moving at different velocities. Stimulus size: 10° × 0.4°. Note the bin widths for PSTHs for stimulus velocities 6.6°/s, 19.8°/s and 33°/s were 22 ms while those for the velocity 46.2°/s, the bin width was 6 ms. (B) Velocity-tuning of peak spike-responses of the same cell shown in (A). Note that during PTV inactivation there is a substantial increase in the magnitude of responses as well as substantial increases in DSI especially at velocities of 6.6°/s and 19.8°/s. (C) Preferred velocities of area 17 cells before vs. those during cooling. Note also that in a couple of cells (a and b), PTV cooling resulted in upward shifts in the preferred velocities. Finally, note that the numbers indicate the number of data points that overlap. (D) Effects of PTV cooling on the magnitude of spike-responses of area 17 cells. ! In (C) and (D) denote the cell marked in lower panel of (B). (E) DSIs of area 17 cells at stimulus velocities optimal before cooling. Note in three cells, cooling PTV resulted in large (≥20%) changes in their DSIs. *Indicates cell in which inactivation of PTV resulted in complete reversal of preferred direction.