Responses of snake muscle spindles to mechanical and electrical stimulation

Responses of the sensory ending of snake muscle spindle to mechanical and electrical stimulation were examined. In the short-capsule spindle the dynamic index increases more rapidly with increase in initial muscle length. The threshold muscle length for initiating a long sustained discharge from the short-capsule spindle is significantly higher than that for the long-capsule spindle while the position sensitivity is similar in the two types of spindle. The relation between rate of discharge of the ending and current applied to the impulse initiating site was found to be similar in both types of spindle.