Development and validation of an automated system for detection and assessment of scratching in the rodent

► Paw motion detector validated vs. human observer for measuring scratching in mice. ► PMD system uses EM field perturbation by metal paw band to detect scratches. ► PMD validated pharmacologically with histamine, 48/80, chloroquine, and DPH. ► Showed homolaterality/homotopic site specificity in scratch detection. ► Power analysis: 40% changes in scratching detectable at alpha = .05 with 4 mice.