Mechanosensory origins of “wet dog shakes” – a tactic used by many hairy mammals – uncovered in mice

“Wet dog shakes” – a common reflex behavior shared among many hairy mammals and designed to expel water and irritants from their coats – happens when particular mechanoreceptors are activated, researchers studying mice report. Many furry mammals engage in rapid body twists known as "wet dog shakes" to effectively remove water from their fur, as well as to eliminate irritants like tangles or parasites, particularly in areas on the neck and back that are largely unreachable by self-grooming or licking. However, despite the commonality of this behavior across species, the neural mechanisms underlying these shakes have remained largely unexplored. Using combined optogenetic, physiological, and behavioral approaches, Dawei Zhang and colleagues evaluated the neurobiological foundations of the wet dog shake behavior in mice. Zhang et al. found that mechanosensation mediated by the Piezo2 gene is essential for the wet dog shake response evoked by oil droplets applied to the backs of mice. According to the findings, mechanoreceptors known as “C-LTMRs,” which primarily innervate the hair follicles of the undercoat, are the key sensory players in this behavior. C-LTMRs, which are typically involved with pleasant affective touch, are connected to spinoparabrachial neurons that transmit sensory signals to the parabrachial nucleus in the brainstem. The authors found that optogenetic activation of C-LTRMs also elicited wet dog shakes without applying oil droplets. Moreover, inhibiting spinoparabrachial neuron synapses and excitatory neurons in the parabrachial nucleus disrupts the wet dog shake response triggered by both oil droplets and C-LTMR activation.