Selective nerve stimulation in an acute rabbit model

Artificial muscle activation by electrical stimulation of motor nerves is characterized by poor force gradation and a relative fast onset of muscle fatigue. Force gradation would improve and the onset of fatigue would be delayed by primarily activating the small-diameter motoneurons. In this study the effects of selective small fiber activation stimulation was investigated in an acute rabbit model. Acute animal experiments were conducted using an isometric setup of medial gastrocnemius. The muscle was activated through a tripolar cuff electrode placed on the tibial nerve. Selective small fiber activation was obtained using selective anodal blocking. The study shows that orderly recruitment can be obtained in the rabbit. However the nerve responses to stimulation are different from what has been described in cat and dog. Break excitation occurs at relative low currents and can only be prevented by extending the pulse with a relative long gradual decay.