A Peltier device attached to a specially designed silver probe was used to reversibly inactivate areas 20a and 20b (Tusa and Palmer, 1980) by cooling the probe to ~10°C, and subsequently rewarming it back to 36°C (Figure 1A). The foot of the probe covered almost all of areas 20a and 20b located on the dorso-lateral surface of cerebral hemisphere and the part of posterior suprasylvian area behind posterior suprasylvian gyrus (Figure 1A). The probe and the opening were sealed with vacuum grease, which also acted as a thermal insulator. At the end of each experiment, cooling probe’s location was checked by careful inspection of indentation marks left by the probe on the dura over PTV. We related these marks to the location of areas 20a and 20b (Tusa and Palmer, 1980) and PS area (Updyke, 1986). In several control experiments, we monitored the temperature and neuronal activity of the cortex under and around the cooling probe using a pair of micro-thermo-couples (25 μm thick wires) glued to the recording electrode. Monitoring was conducted before, during and after rewarming PTV cortex at various (0–11 min) time intervals and at various depths below the cortical surface.