Functions and differences of EEG acquisition local electrode and reference electrode

The electrodes placed on the scalp are active electrode ). The recorded EEG signal is the difference between the active electrode and the reference electrode.

The reference electrode, also known as the reference electrode or Standard electrode, is placed at a relatively zero electrical point in the body.

If the body has a zero electrical point, the reference electrode is placed at this point, and the potential difference between the other parts of the scalp and the electrode at this point is equal to the absolute value of the latter's potential change. However, in theory, this zero-power point refers to the point that is infinitely far from the body when the body is located in the electrolyte fluid, in fact, we can use a point on the body as far as possible from the brain. Therefore, if you select the trunk or limbs, the EEG will be mixed into a greater amplitude than that of the brain, which is also the reason why the EEG record uses the earlobe, nose tip, or mastochoid as the reference electrode. However, the reference electrode at the tip of the nose may cause a false trace of baseline instability due to high sweating. The reference electrodes such as the mastostomy and mandibular part can also cause ECG and vascular fluctuations. The record points near CZ can also be used as the reference electrode, and the M1 and M2 mastostomy locations can also be used as the EEG record points, which will help the system observe the EEG characteristics of the mastostomy.

In addition, a ground electrode is required for the study of ERP ). The grounding electrode is usually placed in the front of the head, or in any part of the head and body. This electrode helps eliminate 50 weeks of interference.

Functions and differences of EEG acquisition local electrode and reference electrode