Fig. 2. (A ) Schematic representation of a lumbar spinal cord slice showing the position of recording and stimulating electrodes. (B ) Infrared videomicroscopy of motor neuron in a spinal cord slice, with patch pipette electrode apposed to the cell body. (C ) Excitatory postsynaptic currents recorded in a motor neuron from a 1-day-old mouse under voltage clamp at a holding potential of −60 mV. Currents were evoked by electrical stimulation in the dorsal horn area. Arrows indicate where peak excitatory postsynaptic current (EPSC) amplitudes were measured. (D ) Current–stimulus intensity relation of the EPSCs from the experiment illustrated in (C ). Peak EPSC amplitudes were plotted against stimulus strength.