Synchronization of presynaptic input to motor units of tongue, inspiratory intercostal, and diaphragm muscles

摘要: The respiratory central pattern generator distributes rhythmic excitatory input to phrenic, intercostal, and hypoglossal premotor neurons. degree which this shapes motor neuron activity can vary across muscles pools. We evaluated the extent drive synchronizes activation of unit pairs in tongue (genioglossus, hyoglossus) chest-wall (diaphragm, external intercostals) using coherence analysis. This is a frequency domain technique, characterizes relative strength neural inputs that are common each recorded units. also examined two muscles, as our previous work shows that, despite being antagonists, they strongly coactivated during inspiratory phase, suggesting from neurons distributed broadly throughout motoneuron pool. All showed highly correlated low-frequency range (1–8 Hz), reflecting fundamental its harmonics. Coherence either within or was similar, consistent with Interestingly, units diaphragm intercostal significantly higher 10–20-Hz bandwidth than tongue-muscle propose lower over reflects larger constellation presynaptic inputs, collectively lead reduction between motoneurons band. This, turn, may reflect simplicity compared greater diversity functions fulfilled by tongue.