Effect of desynchronized inputs on compound sensory and muscle action potentials

Muscle Nerve. 1988 Jul;11(7):694-702. doi: 10.1002/mus.880110705.

Abstract

Stimulation of the second (S1) or third (S2) digit elicits a median sensory potential at the wrist. Similarly, a shock applied to the median (Sm) or ulnar (Su) nerve at the wrist evokes a sensory potential of the fourth digit and a muscle potential over the thenar eminence. Hence, a concomitant application of S1 and S2 or Sm and Su with varying interstimulus intervals simulates the effect of desynchronized inputs. In 10 hands, a shift in latency on the order of 1 msec between S1 and S2 or Sm and Su caused a major reduction in sensory potential by as much as 30-40% but little change in muscle action potential. A latency difference slightly less than one-half the total duration of unit discharge maximized the phase cancellation between the two components and consequently the loss of area under the waveform.

MeSH terms

  • Action Potentials
  • Electrodiagnosis
  • Hand / innervation*
  • Humans
  • Muscles / innervation*
  • Muscles / physiology
  • Neural Conduction
  • Reaction Time
  • Sensation / physiology*