Overall, our goal is to use quantify the links between cellular properties and system function.  Perhaps the most important concept emerging from recent research is that neuromodulatory synaptic inputs to the spinal cord adapt the spinal neuron properties for different motor tasks.  In the figure shown here, the monoamines, which are very strong neuromodulators of spinal neurons, transform the properties of a spinal motoneuron (on left; superimposed on an outline of the spinal cord).  Motoneurons connect directly to muscle fibers and thus implement all motor commands.  When monoaminergic drive to the cord is low or absent, motoneurons track their synaptic inputs accurately but with low gain (green trace).  This type of motoneuron behavior is likely appropriate for small but precise movements.  With a steady background of monoaminergic drive, the same input is markedly amplified and prolonged (green traces), due to activation of persistent inward currents.  The result is a strong and steady motor output that is appropriate for maintained posture.  Recent work in our lab is revealing that disruptions in the monoaminergic control of spinal neurons play an important role in the distortions in motor output that occur in spinal cord injury, hemiparetic stroke and ALS.