Soft cavity model for touch mechanoreceptors under static and sliding contact

We mimic the mechanical response of touch mechanoreceptors by that of a gas cavity embedded in an elastic semicylinder, as a fingertip analog. Using tribological experiments combined with optical imaging, we measure the dynamics and deformation of the cavity as the semicylinder is put in static contact or slid against model rough surfaces at constant normal force and velocity. We propose an elastic model to predict the cavity deformation under normal load showing that membrane mechanical stresses are anisotropic and we discuss its possible biological consequences. In friction experiments, we show that the cavity shape fluctuations allow for texture discriminations.