The EOG channel functions by picking up the charge from the?

The EOG (Electrooculogram) channel is designed to detect the electrical potential generated by eye movements. Specifically, it captures the charge difference between the cornea and the retina of the eye. The cornea, which is more positively charged compared to the retina, creates a measurable potential when the eye moves in different directions. This potential difference provides data that helps to identify various stages of sleep and eye movement activity.

Understanding this mechanism is crucial in a polysomnographic study, as eye movements are closely associated with different sleep stages, including REM sleep. The other options do not adequately address the specific source of the electrical signals measured by the EOG; for example, the scalp relates to EEG readings, and the brain itself does not produce the specific charge detected by the EOG. Therefore, recognizing the role of the cornea in generating the charge helps understand the function of the EOG channel in sleep studies.