Stimulation of the Skin and Dental Pulps

To quantify the cortical excitation responding to electrical stimulation of the regions innervated by the maxillary and mandibular nerves, we inserted bipolar electrodes, which were made from enamel-coated copper wire (diameter = 80 μm), into the whisker pad skin, mandibular first molar pulp (Figure 1C), and mentum skin (3). Five rectangular voltage pulses (5 V, 100-μs duration, 20 ms interstimulus interval) were applied by a stimulator (STG2008, Multi-Channel Systems, Reutlingen, Germany) at 0.05 Hz to obtain stable cortical responses.