Temperature dependence of withdrawal latencies. A. Response time for rat hind-limb paw withdrawal (lick or lift) from a cold plate set at various temperatures for unrestrained, freely moving rats. B. Paw withdrawal latencies for left and right hind-limbs in lightly restrained rats. Note the similar results obtained with these two methods and the close correspondence between the values for left and right limbs in restrained animals. Data shows mean ± SEM for 9 rats.*** p < 0.001 vs. 20°C readings.