Proprioceptive Leg Reflexes in Cockroaches

Abstract

1. Cockroaches have been found to run with stepping frequencies up to 20 cyc./sec. At the higher frequencies mesothoracic amputees do not exhibit the gait adaptations characteristic at lower frequencies. 2. Proprioceptive leg reflexes can follow input frequencies at more than 20 cyc./sec., without phase shift over the frequency spectrum. The myotatic reflex output shows some phase lead with respect to leg position. 3. The contralateral leg responds less strongly and is 180° out of phase with respect to the response of the stimulated leg. Legs in other segments show even weaker responses which are variable in sign. 4. The nervous reflex effects are competent to influence co-ordination at all frequencies found in normal locomotion. The muscular abilities presumably set a limit to higher speeds of running.