Computational And Numerical Simulation Of The Biomechanics Of The Rat’S Vibrissa. Preliminary Study Of The Interaction With Surface Microstructures

Abstract

Vibrissae are specialized hairs located on the snout of several mammals, particularly in rats. Commonly they are involved in the tactile sensation; they allow the exploration and recognition of the surroundings through periodical forward and backward movements. The mechanical events evocated by contact are transmitted to the vibrissal follicle located at the whisker base, where they are transduced into electrophysiological signals that go from the afferent neurons to the primary somatosensory cortex. Spatial orientation, object localization and texture discrimination are some of the tasks that rats can do with this sophisticated system. Particularly in the latter case, the rat can discriminate between textures with a difference of 30 µm in roughness. This excellent capacity makes the vibrissal system an interesting subject for biological studies, as well as for its possible engineering applications. This work presents a two-dimensional numeric-computational model through a finite element formulation for the prediction of mechanical behavior of vibrissae in contact with surfaces of variable roughness. To this end, this study has been restricted to the analysis of discrete events in the whisker kinematics resulting from its collision with microstructures of surfaces. The possible correspondence between the obtained results in terms of displacements, stresses and momentum with the neural activity from electrophysiological studies on the literature is analyzed. This work is a preliminary stage in the development of a complex and general model that will allow the study of the correlation between the mechanical behavior with the neural activity of the vibrissal system.