Beta activity is 'fast' activity. It has a frequency of 14 and greater Hz. It reflects desynchronized active brain tissue. It is usually seen on both sides in symmetrical distribution and is most evident frontally. It may be absent or reduced in areas of cortical damage.
It is generally regarded as a normal rhythm and is the dominant rhythm in those who are alert or anxious or who have their eyes open.
It is the state that most of brain is in when we have our eyes open and are listening and thinking during analytical problem solving, judgment, decision making, processing information about the world around us.
Beta would represent overdrive or hyperdrive in our car scenario.
The beta band has a relatively large range, and has been divided into low, midrange and high.
Low Beta (12-15 Hz), formerly "SMR":
Distribution: localized by side and by lobe (frontal, occipital, etc)
Subjective feeling states: relaxed yet focused, integrated
Associated tasks & behaviors: low SMR can reflect "ADD", lack of focused attention
Physiological correlates: is inhibited by motion; restraining body may increase SMR
Effects of Training: increasing SMR can produce relaxed focus, improved attentive abilities,
Midrange Beta (15-18 Hz)
Distribution: localized, over various areas. May be focused on one electrode.
Subjective feeling states: thinking, aware of self & surroundings
Associated tasks & behaviors: mental activity
Physiological correlates: alert, active, but not agitated
Effects of Training: can increase mental ability, focus, alertness, IQ
High Beta (above 18 Hz):
Distribution: localized, may be very focused.
Subjective feeling states: alertness, agitation
Associated tasks & behaviors: mental activity, e.g. math, planning, etc.
Physiological correlates: general activation of mind & body functions.
Effects of Training: can induce alertness, but may also produce agitation, etc.