Phase-dependent responses evoked in limb muscles by stimulation of medullary reticular formation during locomotion in thalamic cats.

摘要: Electromyographic and kinematic responses of all four limbs were studied when loci within the medullary reticular formation (MRF) stimulated (30-ms train 0.2-ms pulses at 300 Hz, strength 35 microA) during treadmill locomotion in spontaneously walking thalamic cats. Responses could be evoked flexor or extensor muscles any given limb by such stimulation, depending on time step cycle which stimulus was delivered. Stimulation normally excited but either excite inhibit exact position electrode. Excitatory often followed a short period inhibition activity. The opposing same girdle were, general, reciprocally organized. For instance, delivered swing phase ipsilateral excitatory both that contralateral limb. stance muscles. also observed fore- hindlimbs well organized with respect to locomotor cycle. Seventy-five percent occurred 8-20 ms onset train. one (e.g., an other) had similar latencies, suggesting synchronously sides body rather than being consequence other. Although majority muscle elicited its activity, occasionally there no activity absent despite muscle. trains stimuli potent enough affect trajectory, reflected changes offset most Thus effectively changed duration these overall Longer (200 ms) markedly amplified point completely resetting rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)