The McGill Physiology Virtual Lab

Biological Signals Acquisition

EOG tests > procedure

Horizontal EOGs in these experiments will be recorded with silver/silver chloride surface electrodes. These electrodes have been specially designed for recording potentials from the skin.

Thoroughly clean the skin on the side of each eye (the area between the eye and the hairline) and in the middle of the subject's forehead with alcohol pads. Dry the cleansed surface with a gauze pad. The correct locations for the placement of each electrode is illustrated to the right below.
Have the subject look straight ahead. Place an electrode, with its long axis vertical, between the hairline and the corner of each eye, centering it to match the position of the pupil of the subject's eye. Place the third electrode in the center of the subject's forehead.

Connect the EOG electrodes to the cable provided. Attach the yellow and orange connectors to the electrodes near the eyes, and the green electrode to the reference electrode in the center of the head.

The electrode leads are fed to the isolated amplifier in the interface panel. The output signal from this amplifier is sent to the A/D board in the computer to be sampled.

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