Crossed spinal soleus muscle communication demonstrated by H‐reflex conditioning

Introduction: A conditioning volley to the ipsilateral tibial nerve (iTN) inhibits contralateral soleus (cSOL) electromyographic activity at latencies of 37–41 ms. This is evidence for spinal muscular communication in opposing limbs. The aim of our study was to determine whether the cSOL H‐reflex would be inhibited in a similar manner. Methods: Thirteen subjects participated in two experiments: (1) stimuli delivered to the iTN at 85% of the maximal peak‐to‐peak M‐wave (85% M‐max) with a pre‐contracted cSOL; (2) 510 stimuli delivered at 85% M‐max to the iTN with a test volley delivered to the contralateral tibial nerve at interstimulus intervals of −6 to 100 ms. Results: Significant inhibition was observed in the cSOL H‐reflex when conditioning stimuli were delivered 3–33 ms before the test H‐reflex. Conclusions: The activity of this spinal pathway can be quantified using H‐reflex conditioning to provide a controlled model for further studies of this response. Muscle Nerve, 2011

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