Spindle Model Responsive to Mixed Fusimotor Inputs: an updated version of the Maltenfort and Burke (2003) model

Laura Schmid,Mitchell Maltenfort,Oliver Röhrle,Thomas Klotz,Utku Ş Yavuz

doi:10.36903/physiome.19070171.v2

Abstract

The muscle spindle model presented in Maltenfort and Burke (2003) calculates muscle spindle primary afferent feedback depending on the muscle fibre stretch and fusimotor drive. The aim of this paper is to provide an updated version of the model, which is now capable of replicating the originally published data. This is achieved by modifying the equations describing the modulation of the muscle spindle output in response to dynamic fusimotor drive. EDITOR'S NOTE V2: Showing manuscript and model files.

Highlights

Muscle spindles can be found in almost all skeletal muscles and make the most important contribution to proprioception (Macefield and Knellwolf, 2018)
The muscle spindle model by Maltenfort and Burke (2003) predicts primary afferent feedback depending on the muscle stretch and fusimotor drive
The model was validated using data recorded from cat muscle spindles during ramp-and-hold and sinusoidal stretches (Crowe and Matthews, 1964; Hulliger et al, 1977a,b)

Summary

Introduction

Muscle spindles can be found in almost all skeletal muscles and make the most important contribution to proprioception (Macefield and Knellwolf, 2018). The muscle spindle model by Maltenfort and Burke (2003) predicts primary afferent feedback depending on the muscle stretch and fusimotor drive. Grandjean and Maier (2014) previously adapted the Maltenfort and Burke (2003) model to improve the predicted physiological behaviour in the presence of fusimotor drive They did not publish their code and the shown results could not be reproduced with the provided equations. This work presents a model capable of replicating the muscle spindle firing rates during ramp-and-hold and sinusoidal stretches while considering variable fusimotor drives as shown in Fig. 4 and Fig. 5 of the original publication. Note that we will refer to the model based on the equations published in Maltenfort and Burke (2003) as original model and to our model as the updated model

Objectives

Discussion

Conclusion