Brain Waves

Brain Frequency Chart

At the root of all our thoughts, emotions and behaviours is the communication between Neurons within our Brains called Brain Waves. Brain waves are produced by synchronised electrical pulses from masses of neurons communicating with each other.

It is important to know that all humans display five different types of electrical patterns or Brain Waves across the cortex. The brain waves can be observed with an EEG that is a tool that allows researchers to note brain wave patterns. Each brain wave has a purpose and helps serve us in optimal mental functioning. The human brain’s ability to become flexible and/or transition through various brain wave frequencies plays a large role in how successful we are at managing stress, focusing on tasks, and getting a good night’s sleep. If one of the five types of brain waves is either overproduced or under produced in our brain, it can cause problems. For this reason, it is important to understand that there is no single brain wave that is better or more optimal than the others.

Each serves a purpose to help us cope with various situations – whether it is to help us process and learn new information or help us calm down after a long stressful day. The five brain waves in order of highest frequency to lowest are as follows: gamma, beta, alpha, theta, and delta.^[1]

Neural Oscillations

Neural Oscillations have been most widely studied in neural activity generated by large groups of neurons. Large-scale activity can be measured by techniques such as EEG. In general, EEG signals have a broad spectral content similar to pink noise, but also reveal oscillatory activity in specific frequency bands. The first discovered and best-known frequency band is alpha activity (7.5–12.5 Hz) that can be detected from the occipital lobe during relaxed wakefulness and which increases when the eyes are closed. Other frequency bands are: delta (1–4 Hz), theta (4–8 Hz), beta (13–30 Hz) and gamma (30–70 Hz) frequency band, where faster rhythms such as gamma activity have been linked to cognitive processing. Indeed, EEG signals change dramatically during sleep and show a transition from faster frequencies to increasingly slower frequencies such as alpha waves. In fact, different sleep stages are commonly characterized by their spectral content. Consequently, neural oscillations have been linked to cognitive states, such as awareness and consciousness.^[2]

Frequency response

In response to input, a neuron or neuronal ensemble may change the frequency at which it oscillates, thus changing the rate at which it spikes. Often, a neuron's firing rate depends on the summed activity it receives. Frequency changes are also commonly observed in central pattern generators and directly relate to the speed of motor activities, such as step frequency in walking. However, changes in relative oscillation frequency between different brain areas is not so common because the frequency of oscillatory activity is often related to the time delays between brain areas.^[3]

Alpha Waves

Alpha waves are neural oscillations in the frequency range of 7.5–12.5 Hz[1] arising from synchronous and coherent (in phase or constructive) electrical activity of thalamic pacemaker cells in humans. They are also called Berger's wave in memory of the founder of EEG.^[4]

This frequency range bridges the gap between our conscious thinking and subconscious mind. In other words, alpha is the frequency range between beta and theta. It helps us calm down when necessary and promotes feelings of deep relaxation. If we become stressed, a phenomenon called alpha blocking may occur which involves excessive beta activity and very little alpha. Essentially the beta waves block out the production of alpha because we become too aroused.

Frequency range: 8 Hz to 12 Hz (Moderate)
Too much: Daydreaming, inability to focus, too relaxed
Too little: Anxiety, high stress, insomnia, OCD
Optimal: Relaxation
Increase alpha waves: Alcohol, relaxants, some antidepressants^[5]

Beta Waves

Beta wave, or beta rhythm, is the term used to designate the frequency range of human brain activity between 12.5 and 30 Hz (12.5 to 30 transitions or cycles per second). Beta waves can be split into three sections: Low Beta Waves (12.5–16 Hz, "Beta 1 power"); Beta Waves (16.5–20 Hz, "Beta 2 power"); and High Beta Waves (20.5–28 Hz, "Beta 3 power"). Beta states are the states associated with normal waking consciousness.^[6]

These are known as high frequency low amplitude brain waves that are commonly observed while we are awake. They are involved in conscious thought, logical thinking, and tend to have a stimulating affect. Having the right amount of beta waves allows us to focus and complete school or work-based tasks easily. Having too much beta may lead to us experiencing excessive stress and/or anxiety. The higher beta frequencies are associated with high levels of arousal. When you drink caffeine or have another stimulant, your beta activity will naturally increase. Think of these as being very fast brain waves that most people exhibit throughout the day in order to complete conscious tasks such as: critical thinking, writing, reading, and socialization.

Frequency range: 12 Hz to 40 Hz (High)
Too much: Adrenaline, anxiety, high arousal, inability to relax, stress
Too little: ADHD, daydreaming, depression, poor cognition
Optimal: Conscious focus, memory, problem solving
Increase beta waves: Coffee, energy drinks, various stimulants^[7]

Delta Waves

A delta wave is a high amplitude brain wave with a frequency of oscillation between 0.5–4 hertz. Delta waves, like other brain waves, are recorded with an electroencephalogram (EEG) and are usually associated with the deep stage 3 of NREM sleep, also known as slow-wave sleep (SWS), and aid in characterizing the depth of sleep.^[8]

These are the slowest recorded brain waves in human beings. They are found most often in infants as well as young children. As we age, we tend to produce less delta even during deep sleep. They are associated with the deepest levels of relaxation and restorative, healing sleep. They have also been found to be involved in unconscious bodily functions such as regulating heart beat and digestion. Adequate production of delta waves helps us feel completely rejuvenated after we wake up from a good night’s sleep. If there is abnormal delta activity, an individual may experience learning disabilities or have difficulties maintaining conscious awareness (such as in cases of brain injuries).

Frequency range: 0 Hz to 4 Hz (Slowest)
Too much: Brain injuries, learning problems, inability to think, severe ADHD
Too little: Inability to rejuvenate body, inability to revitalize the brain, poor sleep
Optimal: Immune system, natural healing, restorative / deep sleep
Increase delta waves: Depressants, sleep^[9]

Gamma Waves

A gamma wave is a pattern of neural oscillation in humans with a frequency between 25 and 100 Hz, though 40 Hz is typical.According to a popular theory, gamma waves may be implicated in creating the unity of conscious perception. ^[10]

These are involved in higher processing tasks as well as cognitive functioning. Gamma waves are important for learning, memory and information processing. It is thought that the 40 Hz gamma wave is important for the binding of our senses in regards to perception and are involved in learning new material. It has been found that individuals who are mentally challenged and have learning disabilities tend to have lower gamma activity than average.

Frequency range: 40 Hz to 100 Hz (Highest)
Too much: Anxiety, high arousal, stress
Too little: ADHD, depression, learning disabilities
Optimal: Binding senses, cognition, information processing, learning, perception, REM sleep
Increase gamma waves: Meditation^[11]

Theta Waves

Theta waves generate the theta rhythm, a neural oscillatory pattern in electroencephalography (EEG) signals, recorded either from inside the brain.In human EEG studies, the term theta refers to frequency components in the 4–7 Hz range, regardless of their source. Cortical theta is observed frequently in young children. In older children and adults, it tends to appear during meditative, drowsy, hypnotic or sleeping states, but not during the deepest stages of sleep.^[12]

This particular frequency range is involved in daydreaming and sleep. Theta waves are connected to us experiencing and feeling deep and raw emotions. Too much theta activity may make people prone to bouts of depression and may make them highly suggestible based on the fact that they are in a deeply relaxed, semi-hypnotic state. Theta has its benefits of helping improve our intuition, creativity, and makes us feel more natural. It is also involved in restorative sleep. As long as theta isn’t produced in excess during our waking hours, it is a very helpful brain wave range.

Frequency range: 4 Hz to 8 Hz (Slow)
Too much: ADHD, depression, hyperactivity, impulsivity, inattentiveness
Too little: Anxiety, poor emotional awareness, stress
Optimal: Creativity, emotional connection, intuition, relaxation
Increase theta waves: Depressants^[13]