What is happening in Haiti? What is wrong with me? Add AI content Brain Waves Depending on the frequency, waves can be categorised as delta (1–4 Hz) theta (4–8 Hz) alpha (8–13 Hz) (which is sometimes divided into alpha 1 (8–10 Hz) and alpha 2 (11–13 Hz)) beta (more than 13 Hz). Another category of very high (30–40 Hz) frequencies is referred to as gamma waves Areas of the brain The brain can be divided