Figure 1. Resting discharge of C cold fibre at room temperature.
A, the resting discharge is temporarily suppressed by sudden warming of the receptive field (RF) from 31 °C to 35 °C (the Peltier device was initially set to 31 °C, since at that temperature the discharge was the same as with the device removed). B, from a holding temperature of 35 °C, at which the unit is silent, activity is initiated by cooling the RF to 31 °C. Time bar: 5 s (NB the nerve signal in this figure and in Figs 4 and 6 has been subjected to a ‘grass-cutting’ filter to reduce noise, so that spike amplitudes appear to be more variable than they actually are).