Crossed segmental inhibition in muscles

Abstract

1. 1. In decapitate frogs the response of both gastrocnemius muscles to constant velocity stretch was studied with one muscle under constant preloading and the other under a range of preloadings.2. 2. The reflex response was first elicited at a threshold stretch velocity of approximately 40 mm/sec and subsequently increased for higher stretch velocities.3. 3. The effect of increasing the preloading of one muscle was to decrease the response of the muscle with constant preload, but the velocity threshold (40 mm/sec) did not change.4. 4. Tests of the fall time of frogs in a landing simulation and the stretch response results suggest that the frog may utilize a predictive control system to facilitate landing.5. 5. Results suggest a non-uniform distribution of excitatory and inhibitory effects on the motorneurons.