A feedback-controlled dynamic linear actuator to test foot withdrawal thresholds in rat

UMMS Affiliation

Department of Physiology

Publication Date


Document Type



Analgesics, Non-Narcotic; Animals; Behavior, Animal; Capsaicin; Feedback; Foot; Functional Laterality; Male; Pain; Pain Measurement; Pain Threshold; Physical Stimulation; Probability; Rats; Rats, Wistar; Reaction Time; Skin; Time Factors


Life Sciences | Medicine and Health Sciences


We describe a method for evaluating the threshold for cutaneous mechanical sensation in rodents, based on a stimulator that drives a probe against the plantar surface of the foot. The stimulator applies loads that can be either constant or linearly increased. We describe withdrawal responses, including forms of movement that precede foot withdrawals. With constant stimuli, response latency declines in a nonlinear fashion as stimulus magnitude is increased. With ramped stimuli the effect of loading rate is complex, reflecting both the rate of change of the stimulus and the animal's reaction time. We demonstrate the utility of using ramped stimuli in experiments that show that thresholds vary spatially across the foot and experiments that show that intradermal capsaicin injections cause allodynia but not hyperalgesia.

DOI of Published Version



J Neurosci Methods. 2007 Jun 15;163(1):44-51. Epub 2007 Feb 16. Link to article on publisher's site

Journal/Book/Conference Title

Journal of neuroscience methods

Related Resources

Link to Article in PubMed

PubMed ID