Many experiments performed in somatosensory research rely upon measuring or estimating the force at which an animal lifts its paw in response to a punctate mechanical stimulus. While mechanical stimulators are now available, the vast majority of methods utilize a series of nylon monofilaments (modern renditions of “von Frey hairs” i.e., Wynnes Symmes filaments, Stoelting Corp), each of which produces a characteristic force (Bove et al 2003). The use of these devices is subject to limitations of the accuracy of the devices, as well as experimenter error and bias (Bove 2006; Bove et al 2003; Fruhstorfer et al 2001). These potential measurement errors make the tests less sensitive, making false negative results more likely. Here we describe studies of nociception in rats, done using a mechanical stimulator that delivers controlled, accurate forces and is not susceptible to operator bias.
Grigg, Peter; Robichaud, D R.; and Bove, Geoffrey M., "A Feedback-Controlled Dynamic Linear Actuator To Test Foot Withdrawal Thresholds In Rat" (2007). Biomedical Sciences Faculty Publications. 12.