What is the purpose of using electrodes in polysomnography?

The purpose of using electrodes in polysomnography is to measure brain activity, eye movements, and muscle tone. In a polysomnography study, various types of electrodes are placed on the scalp, face, and body to capture electrical signals from the brain (EEG), detect movements of the eyes (EOG), and assess muscle tone (EMG). This data is crucial for diagnosing sleep disorders because it provides insight into the different stages of sleep and any disruptions that may occur during these stages.

Monitoring brain activity allows technologists to identify specific sleep states such as REM and non-REM sleep. Eye movements give additional context about sleep cycles, particularly during REM sleep when these are most prominent. Muscle tone measurements provide information about conditions like REM sleep behavior disorder, where individuals may act out their dreams due to a lack of normal muscle atonia.

Other choices, while involving important physiological measurements, do not summarize the primary function of electrodes in the context of polysomnography as effectively as the correct choice does.