The EGG100C amplifier can be used to isolate elements of the gastrointestinal system for recording, through the use of either surface or needle electrodes. The EGG can be recorded cutaneously with disposable or reusable surface electrodes. Alternatively, the EGG can be recorded using needle electrodes or custom electrode arrays for direct smooth-muscle measurements of the stomach, small intestine and colon. For measurements inside layers of smooth muscle tissue, use the EL450 Teflon-coated needle electrodes. Up to 16 EGG100C amplifiers can be used simultaneously to record surface or subcutaneous signals. JUMP100C jumper connectors are used to reference amplifier inputs to satisfy any combination of monopolar or bipolar recording modes.