Responses of Golgi tendon organs to concurrently active motor units

The effect of a motor unit contraction on a Golgi tendon organ is more fully revealed when the motor unit is stimulated with a random (Poisson) pulse train than when activated with a periodic train. The temporal relationship between the motor unit twitch force and the receptor spike train is exhibited by separately cross-correlating the force and the spike train with the stimulus train. The observed characteristics of the motor unit-receptor interaction are largely preserved even in the presence of activity by other motor units coupled to the same receptor. Our results show that each motor unit influences the firing probability of the receptor in a characteristic way throughout the duration of its twitch.