There are 4 main types of brain waves separate from gamma waves. Each brain wave state has particular characteristics and benefits.
Brainwaves are measured in cycles per second, or Hertz (Hz).
Delta (0-4 Hz) is the slowest pattern, and is associated with dreamless sleep. A handful of advanced spiritual seekers, however, learn to remain alert in this state.
Theta (4-7 Hz) waves are a little faster. The theta brain wave state is associated with dreaming sleep, and more advanced meditative states. In theta states, self-sabotaging filters in the brain are bypassed. Theta is characteristics include: eureka moments, creativity, enhanced memory, stress relief, visionary experiences, integrating positive change. Inexperienced meditation practitioners will likely have trouble getting to the theta wave state, unless they use some type of brainwave entrainment technology.
Alpha brain (7-13 Hz) waves are found in an alert and relaxed brain. Alpha brainwaves are also associated with happiness and joy. Super-learning is common in the higher end of the alpha state because of the relaxed focus associated with this state. You’ve likely experienced alpha waves when you’re absorbed in a movie, t.v. show or a good book. Slower alpha waves create deep relaxation, and is commonly experienced in the twilight state between sleep and waking.
Beta (13-40 Hz) is the most rapid brain wave pattern, and is associated with concentration, arousal, alertness, and cognition. Higher frequency beta is associated with anxiety, disharmony, and disease.
BONUS: Gamma brainwaves (25-140 Hz – especially the 40 Hz area) are associated with large-scale brain activity such as you might use in creative problem solving. Gamma waves occur in short bursts, unlike beta waves which tend to be more persistent. In a brain scan gamma brainwaves appear as high-frequency spindles nestled into slower alpha or theta waves.