How does an electroencephalograph monitor the brain?

An electroencephalograph (EEG) monitors the brain by placing electrodes on the scalp to detect electrical activity produced by neurons. These electrodes measure voltage fluctuations resulting from ionic current flows within the neurons, translating them into waveforms that represent brain activity. The EEG records these signals in real-time, allowing for the assessment of various brain states, such as sleep, alertness, and neurological disorders. The recorded data can help diagnose conditions like epilepsy, sleep disorders, and brain injuries.