Alpha rhythm

Alpha waves are electromagnetic oscillations in the frequency range of 8-12 Hz arising from synchronous and coherent (in phase / constructive) electrical activity of large groups of neurons in the human brain. They are also called Berger's wave in memory of the founder of EEG.

Alpha waves are commonly detected by electroencephalography (EEG) or magnetoencephalography (MEG) and predominantly found to originate from the occipital lobe during periods of relaxation, with eyes closed but still awake. Conversely alpha waves are attenuated with open eyes as well as by drowsiness and sleep. They are thought to represent the activity of the visual cortex in an idle state.

An alpha-like normal variant called mu is sometimes seen over the motor cortex (central scalp) and attenuates with movement, or even with the intention to move.

EEG Biofeedback Training (often called neurotherapy or neurofeedback) is a learning strategy that enables persons to alter their brain waves by getting a feedback of their present state. Alpha Biofeedback has been popular since the 1970s. Increased alpha activities have been reported in persons practicing both Yoga and Zen,.

Neurofeedback is claimed to be effective as an adjunct therapy for ADHD.