EEG

EEG (electroencephalography) is a tool used to monitor the brain’s electrical activity via electrodes placed on the scalp. It records neural oscillations in different frequency bands, each linked to cognitive states:

Delta (1–4 Hz): Deep sleep
Theta (4–8 Hz): Drowsiness, memory processing
Alpha (8–12 Hz): Relaxed wakefulness, attention
Beta (13–30 Hz): Active thinking, working memory, executive control
Gamma (30+ Hz): Higher-order cognition