Spinal Reflex Mechanisms Concerned with Skeletal Muscle

Abstract

This review gives a critical and well-balanced survey of an intricate field that has been advancing rapidly and unevenly and is riddled with controversy. The section on receptors and afferent fibers emphasizes the wide overlap of size of fibers serving different sorts of receptors and the resulting difficulty in limiting stimulation to a single type. Receptors in muscle are treated in detail. The section on motoneurons deals largely with the point of origin of the somatodendritic or B spike, with monosynaptic excitation, postspike hyperpolarization, recurrent collateral inhibition, and direct inhibition. The brief section on interneurons emphasizes their tendency to repetitive firing and its effect on reflex action. The section on reflex responses deals, at length, with reflexes from muscle and concludes with a helpful discussion of reflex activity of fusimotor neurons.