Interactions between focused synaptic inputs and diffuse neuromodulation in the spinal cord

摘要: Spinal motoneurons (MNs) amplify synaptic inputs by producing strong dendritic persistent inward currents (PICs), which allow the MN to generate firing rates and forces necessary for normal behaviors. However, PICs prolong depolarization after initial excitation is removed, tend "wind-up" with repeated activation are regulated a diffuse neuromodulatory system that affects all motor pools. We have shown very sensitive reciprocal inhibition from Ia afferents of antagonist muscles as result PIC amplification related limb configuration. Because tightly focused, shared only between strict anatomical antagonists, this opposes effects descending neuromodulation facilitates PICs. appears control, we hypothesize interacts in "push-pull" fashion, baseline simultaneous allows occur via both disinhibition (and vice versa hyperpolarization). Push-pull control mitigate undesirable associated while still taking full advantage amplification.