A New Six-Channel Electromyograph for Studies on Muscle

To study potentials from several different muscles or parts of the same muscle concurrently so that relative activity could be compared directly, a special apparatus has been developed and tested over the past several years and is reported now for the first time. This apparatus consists essentially of six identical but entirely separate amplifiers, each fitted with a small cathode-ray tube for monitoring. Together with the control unit, they are mounted on the top of a compact metal cabinet. Situated on the floor of the cabinet is the power supply unit next to a light-proof compartment containing six recording cathode-ray tubes. The traces on these tubes are recorded by a 35-mm linagraph camera affixed to the side of the cabinet. This new instrument has been used extensively and with good results in the author´s laboratory for a variety of studies on muscle function.