Perception with whiskers: From contact to action potential - a combination of mechanical and neurophysiological models

SCHARFF M; SCHORR P; ALBARRACIN, AL; FARFÁN FD; ALANCASTRE MIRANDA JH; BEHN C

Budapest

Conferencia; 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS; 2021

Budapest University of Technology and Economics

The somatosensory system of mammals includes the sense of touch. The sense of touch is intensely investigated, wherebypoints of view from very different scientific areas, e.g., neurobiology or robotics, influence the investigations. In this context, thewhisker system of rats is frequently analyzed. The whiskers are long, slender hairs, arranged around the snout of the animals.Whiskers are powerful tactile sensors consisting of the mentioned hair shaft and a supporting hair follicle called follicle-sinuscomplex. A follicle-sinus complex includes many mechanoreceptors of different types, generally categorized in rapid and slowadapting ones, and is highly innervated. Rats can explore their surrounding by moving their whiskers periodically back and forthwith a frequency of 5-25 Hz and an amplitude of approx. 25, [1]. When they get in touch with an object various information canbe collected, see Fig. 1(a). Among others, they can determine the distance to an object, evaluated its shape or surface texture.Doing so, the hair shaft is rotated against the object and gets deformed. The resulting contact force triggers afferent activitytrough mechanoreceptors and connected neurons. The transition form mechanical forces to neuronal activity is called mechanotransduction.This process is essential to understand and adapt the functionality of whiskers because it changes a continuousmechanical stimuli to a discrete sequence of action potentials with varying frequency that is finally sent to the central nervoussystem.The present work represents a further step to build a more in-depth understanding of the mechanotransduction and its significancefor tactile perception. Here, the design of artificial whisker-like sensors is addressed as well as biological aspects. Weprovide a theoretical model, combining the mechanical interaction between a whisker and an object with the mechanotransduction.This theoretic framework allows for a detailed analysis of the inherent system characteristics to evaluated the relationbetween mechanical contact and action potential in the primary afferent neurons. On the one hand, this a key to understand thenatural sense of touch and on the other hand, this could be an efficient signal encoding for applications in robotics.