Electronic Apparatus for Recording and Measuring Electrical Potentials in Nerve and Muscle

Electronic apparatus used in studying action potentials is described. It consists of 1. A variable-frequency stimulator with a volume control which governs the intensity of current used for exciting the nerve or muscle. 2. A trigger circuit synchronizing the sweep of the recording system, a cathode-ray oscilloscope with the stimulator. 3. A recording system, a cathode-ray oscilloscope whose circuit has been altered to permit synchronization with the trigger circuit. 4. A resistance-capacitance-coupled amplifier with one balanced push-pull input stage used as a preamplifier to feed a high-level signal into the differential stage which effectively cancels in-phase signals. This stage is supplied with an input jack permitting its use as the input stage when low-level signals are not encountered. This is followed by three single-ended stages each having an output jack. A theory of nerve conduction is discussed. The formation of diphasic and monophasic wave forms is described and illustrated. A method for measuring conduction rate is also considered.