The lowest frequencies are delta . These are less than 4 Hz and occur in deep sleep and in some abnormal processes also during experiences of empathy state. Delta waves are involved with our ability to integrate and let go. It reflects unconscious mind.
It is the dominant rhythm in infants up to one year of age and it is present in stages 3 and 4 of sleep.
It tends to be the highest in amplitude and the slowest waves. We increase Delta waves in order to decrease our awareness of the physical world. We also access information in our unconscious mind through Delta.
Peak performers decrease Delta waves when high focus and peak performance are required.
However, most individuals diagnosed with Attention Deficit Disorder, naturally increase rather than decrease Delta activity when trying to focus. the inappropriate Delta response often severely restricts the ability to focus and maintain attention. It is as if the brain is locked into a perpetual drowsy state.
Another way to look at Delta is to imagine you are driving in a car and you shift into 1st gear.you're not going to get anywhere very fast. So Delta would represent 1st gear.
Theta would be considered 2nd gear. Not as slow as 1st gear (Delta) but still not very fast.
Alpha would represent neutral or idle. Alpha allows us to shift easily from one task to another.
Beta would represent overdrive or hyperdrive in our car scenario.

Delta waves (0 - 4 Hz). Delta waves are frequencies from 0 to 4 Hz or cycles per second.
It is associated with deep sleep and experiences of empathy and in some abnormal processes.
Delta waves are the lowest brainwaves frequency is thought to represents the gray matter (cortical activity) of the brain.
This is the most predominant brain frequency during deep sleep.
Delta waves are also called delta rhythm, and emanates from the forward portion of the brain and in normal adults.
Delta waves are present only in stage three sleep, stage four sleep, cases of brain injury and coma.
During sleep, delta waves are not present in the other stages (1, 2, and REM).
The delta brainwave have high voltage and low frequency and can be viewed in the encephalogram of a person in deep dreamless sleep.
In the heart a delta wave in the ECG is seen in Wolff-Parkinson-White syndrome.
Delta (0.1 - 3 Hz). Distribution: generally broad or diffused may be bilateral, widespread.
Subjective feeling states: deep, dreamless sleep, non-REM sleep, trance, unconscious.
Associated tasks and behaviors: lethargic, not moving, not attentive.
Physiological correlates: not moving, low- Level of arousal.
Effects of training: can induce drowsiness, trance, deeply relaxed states.

Tare delta waves. These are less than 4 Hz and occur in deep sleep and also during experiences of empathy state.
Delta waves are involved with our ability to integrate and let go and reflects unconscious mind.
It is the dominant rhythm in infants up to one year of age and it is present in stages 3 and 4 of sleep.
It tends to be the highest in amplitude and the slowest waves. We increase
Delta waves in order to decrease our awareness of the physical world. We also access information in our unconscious mind through Delta.
Peak performers decrease Delta waves when high focus and peak performance are required.
However, most individuals diagnosed with Attention Deficit Disorder, naturally increase rather than decrease Delta activity when trying to focus. the inappropriate Delta response often severely restricts the ability to focus and maintain attention. It is as if the brain is locked into a perpetual drowsy state.
Another way to look at Delta is to imagine you are driving in a car and you shift into 1st gear.you're not going to get anywhere very fast. So Delta would represent 1st gear.
Delta (0.1-3 Hz): Distribution: generally broad or diffused may be bilateral, widespread
Subjective feeling states: deep, dreamless sleep, non-REM sleep, trance, unconscious
Associated tasks and behaviors: lethargic, not moving, not attentive
Physiological correlates: not moving, low- Level of arousal
Effects of training: can induce drowsiness, trance, deeply relaxed states

Theta waves starts from 4 to 8 Hz. It relates to the subconscious activity.
It is the predominant frequency during the transition stage between wakefulness and sleep.
Theta waves are noted during creativity, intuition and daydreaming.
It is a repository for memories, emotions and sensations.
Theta waves are strong during internal focus, meditation and prayer.
Theta waves reflect activity from the limbic system, feelings and emotions.
Theta (4-8 Hz). Theta activity has a frequency of 3.5 to 7.5 Hz and is classed as slow activity.
It is seen in connection with creativity, intuition, daydreaming, and fantasizing and is a repository for memories, emotions, sensations.
Theta waves are strong during internal focus, meditation, prayer, and spiritual awareness. It reflects the state between wakefulness and sleep. Relates to subconscious.
It is abnormal in awake adults but is perfectly normal in children up to 13 years old. It is also normal during sleep. Theta is believed to reflect activity from the limbic system and hippocampal regions.
Theta is observed in anxiety, behavioral activation and behavioral inhibition.
When the theta rhythm appears to function normally it mediates and/or promotes adaptive, complex behaviors such as learning and memory. Under unusual emotional circumstances, such as stress or disease states, there may be an imbalance of three major transmitter systems, which results in aberrant behavior.
Distribution: usually regional, may involve many lobes, can be lateralized or diffuse;
Subjective feeling states: intuitive, creative, recall, fantasy, imagery, creative, dreamlike, switching thoughts, drowsy; oneness, knowing.
Associated tasks and behaviors: creative, intuitive; but may also be distracted, unfocused.
Physiological correlates: healing, integration of mind/body.
Effects of Training: if enhanced, can induce drifting, trance- Like state. If suppressed, can improve concentration, ability to focus attention

Alpha waves are from 8 to 12 Hz. Are associated with relaxation, or idling
In this state you can move quickly and efficiently to accomplish whatever task is at hand.
Alpha appears to bridge the conscious to the subconscious.
When Alpha waves predominate most people feel at ease and calm.
Alpha waves represent the white matter or the connections throughout the brain.
The alpha wave also occurs in the normal brainwave when a person who is awake but relaxed; and can be viewed in a electroencephalogram.
An alpha wave is a pattern of smooth, regular electrical oscillations in the human brain that occur when a person is awake and relaxed.
As recorded by the electroencephalograph, alpha waves have a frequency of 8 to 13 hertz. Also called alpha rhythm.
Alpha Waves (8-12 Hz)
Alpha waves are those between 7.5 and 13(Hz). Alpha waves will peak around 10Hz. Good healthy alpha production promotes mental resourcefulness, aids in the ability to mentally coordinate, enhances overall sense of relaxation and fatigue. In this state you can move quickly and efficiently to accomplish whatever task is at hand. When Alpha predominates most people feel at ease and calm. Alpha appears to bridge the conscious to the subconscious.
It is the major rhythm seen in normal relaxed adults -it is present during most of life especially beyond the thirteenth year when it dominates the resting tracing.
Alpha rhythms are reported to be derived from the white matter of the brain. The white matter can be considered the part of the brain that connects all parts with each other.
Alpha is a common state for the brain and occurs whenever a person is alert (it is a marker for alertness and sleep), but not actively processing information. They are strongest over the occipital (back of the head) cortex and also over frontal cortex.
Alpha has been linked to extroversion (introverts show less), creativity (creative subjects show alpha when listening and coming to a solution for creative problems), and mental work.
When your alpha is with in normal ranges we tend to also experience good moods, see the world truthfully, and have a sense of calmness. Alpha is one of the brain's most important frequency to learn and use information taught in the classroom and on the job.
You can increase alpha by closing your eyes or deep breathing or decrease alpha by thinking or calculating.
Alpha-Theta training can create an increase in sensation, abstract thinking and self- Control.
Distribution: regional, usually involves entire lobe; strong occipital w/eyes closed.
Subjective feeling states: relaxed, not agitated, but not drowsy; tranquil, conscious.
Associated tasks and behaviors: meditation, no action.
Physiological correlates: relaxed, healing.
Effects of Training: can produce relaxation.
Sub band low alpha: 8-10: inner-awareness of self, mind/body integration, balance
Sub band high alpha: 10-12: centering, healing, mind/body connection

The Sensory Motor Rhythm (SMR).
Brainwaves of 12 to 15 Hz represent Sensory Motor Rhythm (SMR). This is associated with bodily relaxation.

Beta is a frecuency band between 15 and 18 Hz.
It is predominant when one is focused or during periods of analytical problem solving, judgment, decision making and processing information about the world around us.
Beta waves center around cortical activity and our ability to think and access.
Beta wave is the term used to designate the frequency range of brain activity above 12 Hz (12 transitions or cycles per second).
Beta states are the states associated with normal waking consciousness.
Low amplitude beta with multiple and varying frequencies is often associated with active, busy or anxious thinking and active concentration.
Rhythmic beta with a dominant set of frequencies is associated with various pathologies and drug effects.
Beta (above 12 Hz)
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.
the beta band has a relatively large range, and has been divided into low, midrange and high.

Gamma (26 to 70 Hz). A gamma wave is a pattern of brain waves, associated with perception and consciousness.
Gamma waves are produced when masses of neurons emit electrical signals at the rate of around 40 hertz, but can often be between 26 and upwards of 70 Hz.
By one definition, gamma waves are manifest at 24 Hz and higher, though researchers have recognized that higher level cognitive activities occur when lower frequency gamma waves suddenly double into the 40 Hz range.
Research has shown gamma waves are continuously present during low voltage fast neocortical activity (LVFA), which occurs during the process of awakening and during active rapid eye movement (REM) sleep.
Some researchers do not distinguish gamma waves as a distinct class but include them in beta brain waves.
Gamma waves are involved in higher mental activity and are related with higher reasoning faculties.
Transient periods of synchronized firing over the gamma waveband, of entire banks of neurons from different parts of the brain, have been proposed as a mechanism for bringing a distributed matrix of cognitive processes together to generate a coherent, concerted cognitive act, such as perception.
Gamma waves are associated with solving the binding problem. Recent studies have shown that recognition of new insights occur when patterns jump from 20 to 40 Hz.
It is believed by neuroscientists that gamma activity occurs when various chemical messengers foster efficient communications across large swaths of brain tissue.

Brainwave synchronization is the practice to entrain one's brainwaves to a desired frequency, by means of a periodic stimulus with corresponding frequency. the stimulus can be aural as in the case of binaural beats, or visual, as with a Dreamachine.
Brainwave synchronization is a private case of functional brain connectivity concept, whereas functional connectivity is defined as the temporal correlation between spatially-remote neurophysiological events, expressed as deviation from statistical independence (temporal correlation) across these events in distributed neuronal groups and areas, which produce the brainwaves (for the recent review see Fingelkurts An.A., Fingelkurts Al.A., Kaa S. Functional connectivity in the brain - is it an elusive concept? Neuroscience & Biobehavioral Reviews. 2005, 28(8):827-836). As authors have stated, "the functional brain connectivity has become one of the most influential concepts in modern cognitive neuroscience, especially given the current shift in emphasis from studies of functional segregation to studies of functional integration."
Frequencies that might be used in brainwave synchronization and the related brain waves and mind states.