Reference Electrode
Electrode providing a baseline potential for differential neural recordings relative to active recording sites.
A reference electrode provides the baseline electrical potential against which all active recording sites are measured. Neural signals are recorded as the voltage difference between each site and the reference.
Why it matters: Reference electrode placement and impedance directly affect recording quality. A poor reference introduces noise and artifacts into every channel simultaneously.
Placement options: Skull screw (most common in rodents), silver wire in the brain, dedicated reference site on the probe, or stainless steel wire in the neck muscle.
Key considerations: The reference should be in electrically quiet tissue, have low and stable impedance, and be mechanically secure. Impedance mismatch between reference and recording sites increases common-mode noise.