Altered Consciousness

At the root of all our thoughts, emotions and behaviours is the communication between neurons within our brains. Brainwaves are produced by synchronised electrical pulses from masses of neurons communicating with each other.

Brainwaves are detected using sensors placed on the scalp. They are divided into bandwidths to describe their functions (below), but are best thought of as a continuous spectrum of consciousness; from slow, loud and functional - to fast, subtle, and complex.

It is a handy analogy to think of Brainwaves as musical notes - the low frequency waves are like a deeply penetrating drum beat, while the higher frequency brainwaves are more like a subtle high pitched flute. Like a symphony, the higher and lower frequencies link and cohere with each other through harmonics. / (source)

Our 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 and/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.

Gamma Waves
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

Beta Waves
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

Alpha Waves
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, marijuana, relaxants, some antidepressants

Theta Waves
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

Delta Waves
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 / (source)

The areas that contributed to vision were more active under LSD (right), which was linked to hallucinations Credit: Credit: Imperial College of London

LSD May Chip Away at the Brain's "Sense of Self" Network
Members of the team reporting in Current Biology suspect that the default mode network disintegration, coupled with dampened electrical activity in consciousness-related alpha brain waves, contributes to a temporary loss of a sense of self in some psychedelic drug users, who often describe feeling at one with others and the world around them—an effect scientists call “ego dissolution.” (source)

The Power of Music: Mind Control by Rhythmic Sound
The EEG recording detects the combined electrical activity of thousands of neurons working together in the cerebral cortex. Just like the roar of a crowd at a baseball game, waves of electrical activity in the brain are generated when individual neurons in the cerebral cortex are combined in action. The EEG recordings showed that the waves of brain activity (alpha and beta waves) became synchronized around the auditory rhythm. That is, the ongoing oscillations of brain waves became phase shifted so that the peak of the wave always occurred at a precise point relative to the next beat in the drum rhythm. Rhythmic sound synchronizes brain waves. (source)

Brains of Buddhist monks scanned in meditation study
Dr Josipovic's research is part of a larger effort better to understand what scientists have dubbed the default network in the brain.He says the brain appears to be organised into two networks: the extrinsic network and the intrinsic, or default, network. Dr Josipovic has scanned the brains of more than 20 experienced meditators during the study The extrinsic portion of the brain becomes active when individuals are focused on external tasks, like playing sports or pouring a cup of coffee.

The default network churns when people reflect on matters that involve themselves and their emotions. But the networks are rarely fully active at the same time. And like a seesaw, when one rises, the other one dips down. This neural set-up allows individuals to concentrate more easily on one task at any given time, without being consumed by distractions like daydreaming.

"What we're trying to do is basically track the changes in the networks in the brain as the person shifts between these modes of attention," Dr Josipovic says.Dr Josipovic has found that some Buddhist monks and other experienced meditators have the ability to keep both neural networks active at the same time during meditation - that is to say, they have found a way to lift both sides of the seesaw simultaneously. / (source)