2-Channel Hookup with 4 Electrodes

To record a 2 channel EEG, we recommend the use of 4 silver/silver chloride electrodes.  One jumper cable is used to connect minus inputs for channel 1 and channel 2. Compared with using only 3 electrodes, this setup improves common mode rejection and reduces electrical noise and artifact in the signal.  Using 5 separate electrodes for plus and minus inputs to channel 1 and channel 2 plus a common ground is still an option, and might be preferred in electrically noisy environments.

Below are step-by-step instructions for this 4-electrode setup:

  1. You will need 4 silver/silver chloride electrodes, and one electrode jumper.

  2. Plug the jumper cable into the channel 1 and channel 2 minus inputs.

  3. Plug yellow electrode into channel 1 plus input.

  4. Plug white electrode into channel 2 plus input, and black electrode into ground input.  Plug gray electrode into either end of the jumper cable so that it connects to both 1 and 2 minus inputs.

  5. It is recommended to keep the four electrodes loosely braided or held together with a twist tie.

Final 2-channel hookup with 4 electrodes should look like:

How to Check Ground Impedance:

The two minus inputs will show green on the impedance meter at all times because they are linked together.  For a true impedance check on the gray (reference) electrode, unplug the far end of the jumper from the Neuroamp.  Make sure to plug the jumper back in before starting your session.