EMG activity was filtered and amplified using an A-M System Model 1700 differential AC amplifier. A Gould 4200 digital oscilloscope was used to monitor EMG activity. Electrolytic corrosion was produced using an A-M System Model 2100 Isolated Pulse Stimulator. Digitization
of EMG activity was carried out with a Cambridge Electronic Design CED 1401 Plus waveform analyzer. In general, any commercially available AC amplifier, pulse stimulator, oscilloscope and A-D converter able to operate in the required frequency and voltage ranges can be used.