[Induced locomotion in the myriapod Julus sp]

Coordinated locomotor activity in the decapitated millipede Julus sp. was induced either by mechanical stimulation of the legs with the aid of a treadmile band, or by electrical stimulation of separate parts of the abdominal nervous cord. For the walking induced by mechanical stimulation of the legs, it was shown that: 1) after the "support phase", an additional phase of locomoter cycle, i. e. a "pause phase", is registered; 2) the relationships between kinematic parameters are similar to those recorded during normal walking of the intact millipede and correspond to walking at the lowest velocity. In the case of locomotion induced by electrical stimulation, a "start locomotion threshold" was observed: if stimulation level exceeds this threshold, forward walking is induced being the faster the stronger this stimulation. Besides, the second threshold phenomenon was found - a "threshold of the reversion of locomotion direction". When this threshold is exceeded, forward walking is replaced by backward one. The relationships between kinematic parameters of locomotion induced by electrical stimulation are also similar to corresponding relationships of normal spontaneous walking in the intact millipede, although in this case a "pause phase" is absent.