A Theoretical and Experimental Investigation into the Distribution, Morphology and Function of Pacinian Corpuscles

Abstract

The distribution, morphology and function of the pacinian corpuscle was examined. The distribution in rat feet was recorded using both Magnetic Resonance Imaging (MRI) and dissection. The mechanical properties of the corpuscle were investigated using a theoretical model based upon previous work by (Loewenstein & Skalak, 1966). The model was used to examine how the corpuscle’s structure affects its function in healthy and diseased states. Distribution data gathered by dissection revealed the majority of corpuscles were restricted to the adipose tissue of each foot pad. Densest concentrations were in the rear foot pads. The remainder were located in the digits and in close proximity of bone via the interosseous membrane and wrist ligaments. Localisation near capillaries was common. MRI was not invasive and detected a greater number of corpuscles but held limitations in its ability to separate corpuscles in close proximity. Dissection was invasive and showed a lower number of corpuscles but greater confidence could be contributed to the correct identification of each corpuscle. The theoretical model was developed over three levels: (i) the original model (LSM) as described by Loewenstein and Skalak. (ii) the L2 model where a second order elastic force is added and finally (iii) the L3 model where the parameters are modernised based upon current literature. These models describe how mechanical force is transmitted through the structural components of the corpuscle. The L2 model shows the additional elastic forces overall impact is relatively small. Adjusting the original model's parameters for the L3 model shows decreased sensitivity of the corpuscle. Finally, the L3 model was applied to examine how the high number of lamellae layers associated with Dupuytren’s contracture and other pacinian pathologies reduces the amount of pressure felt at the core, thus providing a potential insight into the cause of loss of touch perception in patients.