A finite-element model of mechanosensation by a Pacinian corpuscle cluster in human skin

Abstract

The Pacinian corpuscle (PC) is the cutaneous mechanoreceptor responsible for sensation of high-frequency (20–1000 Hz) vibrations. PCs lie deep within the skin, often in multicorpuscle clusters with overlapping receptive fields. We developed a finite-element mechanical model of one or two PCs embedded within human skin, coupled to a multiphysics PC model to simulate action potentials elicited by each PC. A vibration was applied to the skin surface, and the resulting mechanical signal was analyzed using two metrics: the deformation amplitude ratio (${\rho }_{\mathrm{1S}}$, ${\rho }_{\mathrm{2S}} )$ and the phase shift of the vibration (${\delta }_{\mathrm{S}1}^{\mathrm{mech}}$, ${\delta }_{\mathrm{S}2}^{\mathrm{mech}} )$ between the stimulus and the PC. Our results showed that the amplitude attenuation and phase shift at a PC increased with distance from the stimulus to the PC. Differences in amplitude ($\rho _{12} )$ and phase shift (${\delta }_{12}^{\mathrm{mech}} )$ between the two PCs in simulated clusters directly affected the interspike interval between the action potentials elicited by each PC (${\delta }_{12}^{\mathrm{spike}} )$. While ${\delta }_{12}^{\mathrm{mech}}$ had a linear relationship with ${\delta }_{12}^{\mathrm{spike}}$, $\rho _{12}$’s effect on ${\delta }_{12}^{\mathrm{spike}}$ was greater for lower values of $\rho _{12}$. In our simulations, the separation between PCs and the distance of each PC from the stimulus location resulted in differences in amplitude and phase shift at each PC that caused ${\delta }_{12}^{\mathrm{spike}}$ to vary with PC location. Our results suggest that PCs within a cluster receive different mechanical stimuli which may enhance source localization of vibrotactile stimuli, drawing parallels to sound localization in binaural hearing.