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Diverse and complex muscle spindle afferent firing properties emerge from multiscale muscle mechanics.

Authors :
Blum KP
Campbell KS
Horslen BC
Nardelli P
Housley SN
Cope TC
Ting LH
Source :
ELife [Elife] 2020 Dec 28; Vol. 9. Date of Electronic Publication: 2020 Dec 28.
Publication Year :
2020

Abstract

Despite decades of research, we lack a mechanistic framework capable of predicting how movement-related signals are transformed into the diversity of muscle spindle afferent firing patterns observed experimentally, particularly in naturalistic behaviors. Here, a biophysical model demonstrates that well-known firing characteristics of mammalian muscle spindle Ia afferents - including movement history dependence, and nonlinear scaling with muscle stretch velocity - emerge from first principles of muscle contractile mechanics. Further, mechanical interactions of the muscle spindle with muscle-tendon dynamics reveal how motor commands to the muscle (alpha drive) versus muscle spindle (gamma drive) can cause highly variable and complex activity during active muscle contraction and muscle stretch that defy simple explanation. Depending on the neuromechanical conditions, the muscle spindle model output appears to 'encode' aspects of muscle force, yank, length, stiffness, velocity, and/or acceleration, providing an extendable, multiscale, biophysical framework for understanding and predicting proprioceptive sensory signals in health and disease.<br />Competing Interests: KB, KC, BH, PN, SH, TC, LT No competing interests declared<br /> (© 2020, Blum et al.)

Details

Language :
English
ISSN :
2050-084X
Volume :
9
Database :
MEDLINE
Journal :
ELife
Publication Type :
Academic Journal
Accession number :
33370235
Full Text :
https://doi.org/10.7554/eLife.55177