Determination of threshold temperature for thermal nociception

The withdrawal latency to a focal heat source is one method that is commonly used to measure thermal nociception and assess analgesia. This measurement indirectly estimates thermal threshold, and its value has been found to depend on the starting temperature and the rate of increase in temperature of the heat source. A one-dimensional heat conduction model was used to convert withdrawal latency to tissue temperature. Results from this model indicate that the withdrawal times for all test conditions correspond to a temperature of 40.2 degree C in the tissue surrounding the nociceptors.