Re-examination of a linear systems approach to the behavior of mammalian muscle spindles.

A model consisting of the parallel arrangement of one position-dependent and three first order velocity-dependent components is proposed in order to describe the behavior of muscle spindles. The responses of spindle receptors to ramp stretches have previously been characterized by fractional power functions; the aim of this study is to generate these functions on the basis of a simple additive linear model. A procedure is described which yields model parameters from responses to ramp and triangular displacements. Tests of the model are performed by comparing its predictions with experimental data from muscle spindles in cat and rat.