The mean peak-firing rate of 28 area 19 neurons before PTV inactivation at 63.55 spikes/s was almost identical to that (63.3 spikes/s) during PTV cooling. However, in a quarter of cells (7/28; 4 complex; 3 simple), inactivation resulted in significant reduction (Figures 2Di, 3Ai,ii), or a complete cessation (Figures 2A,B) of responses to stimuli. In another quarter of the sample (7/28; Figure 2Di) the reductions in magnitude of responses were not significant. The last group included two cells (both complex—one binocular class 4, the other monocular class 5) whose RFs were located at the very periphery of the part of the contralateral hemifield represented in areas 20a and 20b (Figure 1C).