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

Kyle P. Blum, Kenneth S. Campbell, Brian C. Horslen, Paul Nardelli, Stephen N. Housley, Timothy C. Cope, Lena H. Ting

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

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 la 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.

Original languageEnglish
Article numbere55177
Pages (from-to)1-32
Number of pages32
JournaleLife
Volume9
DOIs
StatePublished - Dec 2020

Bibliographical note

Publisher Copyright:
© Blum et al.

ASJC Scopus subject areas

  • General Neuroscience
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology

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