A computational model of insect campaniform sensilla predicts encoding of forces during walking

Control of forces is essential in both animals and walking machines. Insects measure forces as
strains in their exoskeletons via campaniform sensilla (CS). Deformations of cuticular caps embedded
in the exoskeleton excite afferents that project to the central nervous system. CS afferent firing
frequency (i.e. ‘discharge’) is highly dynamic, correlating with the rate of change of the force.
Discharges adapt over time to tonic forces and exhibit hysteresis during cyclic loading. In this
study we characterized a phenomenological model that predicts CS discharge, in which discharge is
proportional to the instantaneous stimulus force relative to an adaptive variable. In contrast to
previous studies of sensory adaptation, our model (1) is nonlinear and (2) reproduces the
characteristic power-law adaptation with first order dynamics only (i.e. no ‘fractional derivatives’
are required to explain dynamics). We solve the response of the system analytically in multiple
cases and use...

Source: Bioinspiration and Biomimetics - September 6, 2021 Category: Science Authors: Nicholas S Szczecinski, Chris J Dallmann, Roger D Quinn and Sasha N Zill Source Type: research