Therefore grimace scales have the potential to monitor and improve the welfare of animals used not only in research, but also in farming and industry. However, while application of the ice pellet to the glass generates a cooling ramp that can be approximately correlated to estimates of the paw withdrawal temperature, the paw being tested needs to remain in contact with the glass to achieve efficient temperature transfer. They helped shape the ideas of operant conditioning in behaviorism. Lancet Neurol. Technology Addiction. 24, 19281939. (2015). The dynamic hot plate test, first described in 1984, uses an increasing temperature ramp rather than a constant temperature. Osteoarthr. As the test is performed in relatively unrestrained rodents, it relies heavily on the animal freely taking up the correct stance, which can be difficult to achieve in mice. Gait analysis methods for rodent models of osteoarthritis. Facebook doi: 10.1016/j.jbspin.2004.01.010, Cox, J. J., Reimann, F., Nicholas, A. K., Thornton, G., Roberts, E., Springell, K., et al. doi: 10.1172/jci42843, Dubner, R. (1983). Methods 31, 7983. The experiment begins by testing the response to a filament estimated to be close to the 50% withdrawal threshold. In fact, it is a requirement for publication of in vivo data in high quality journals that relevant standards and guidelines are strictly adhered to (McGrath et al., 2010). Guidelines for the design and statistical analysis of experiments using laboratory animals. These values are not absolute, as heat thresholds are influenced by the ambient temperature, rate of heating (110C/s), the type (hairy or glabrous) and location of test skin, method of heat transfer, experimental design and skin temperature (for radiant heat only; Pertovaara et al., 1996; Defrin et al., 2006; Rolke et al., 2006). The test begins by assessing the response to a filament of the lowest force (in this case 0.4 grams-force) for a set number of applications (in this case five times). doi: 10.1016/j.jpain.2013.01.770, Ogren, S. O., and Berge, O. G. (1984). Gait analysis in freely walking rodents is used to study changes in limb movement and positioning in models with sensori-motor dysfunction, including Parkinsons disease, spinal cord injury and stroke. 43, 207213. Obviously this cannot be done in rodents, making spontaneous pain difficult to quantify; however new methods to evaluate spontaneous pain are increasingly being reported, including grimace scales, burrowing assays, gait analysis, weight bearing and automated behavioral analysis (for a summary on behavioral tests used in non-stimulus evoked nociception, see Tappe-Theodor and Kuner, 2014).