Notes

Consciousness is when an individual is aware of an environment and able to feel, sense, remember, recognize, and rationalize. Thus, the individual can make decisions. States of consciousness also guide a person’s way of thinking. You may find yourself having multiple thoughts at the same time, or your mind may be cluttered by the many things around you.

There are four major consciousness levels:

Superconscious is a highly attentive state of consciousness and perception. In this level, the thinking and organization occur without the person’s active participation. People experience the level of superconsciousness during advanced meditation stages.
Conscious is when a person is fully awake, alert, and functioning as a human being.
Subconscious is when a person is deeply relaxed as well as just before and after sleep. This includes the state during light meditation and hypnosis.
The dream state occurs when a person is asleep, dreaming, and in a deep unconscious state.
onsciousness is explained by two major theories:

Integrated information theory: In 2004, a neuroscientist and psychiatrist in sleep medicine named Giulio Tononi explained the nature of consciousness using the integrated information theory. According to the theory, consciousness can be correlated mathematically in a geometric manner. It is based on a person’s experience integrated with other parts of various experiences. In other words, all the thinking and organization occur without the person’s active participation. This theory explains situations like choosing a place for dinner, buying a book, voting, etc. You apply your experience and rate the choices based on a desirable value.

Global workspace theory: This theory explains our conscious awareness of inputs from various sensory stimuli. Bernard Baars, a professor of psychology and co-founder of the Association of the Scientific Study of Consciousness, proposed the theory in 1987. According to this theory, images and ideas form together as a unified picture of reality. The input then becomes output, or speech and action. This theory examines how brains function through a series of activities.
Research on consciousness and related theories introduced the study of brain wave activity. Electroencephalograms (EEGs) measure brain-wave patterns. This makes it possible to study the components of waking and sleeping.

Four major brain waves relate to sleep and alertness. Their function and likelihood is slightly different between adults and children. Infants show the most different brain waves as compared to other age groups. The four main brain waves are beta, alpha, theta, and delta.

Beta: These brains waves are common among fully awake, alert people of all ages.

Alpha: These brain waves are most common in adults. They typically occur when a person becomes relaxed and drowsy to the point of closing their eyes.

Theta: These waves are seen in people of all age groups when they are sleeping. They can also be observed in awake infants and children, but are abnormal in awake adults.

Delta: These waves occur when a person is in the dream state. They usually begin to take place about 30 minutes after a person falls asleep. This stage is the deepest level of sleep. Delta waves can be seen in children and infants when they are awake as well, but they are abnormal in adults if they are awake.
While you are sleeping, your brain and body continue to function. Sleep is a periodic, natural, reversible, and near-total loss of consciousness. It is important to a person’s health, growth, and mental function. It is common for a person to experience four to five stages of sleep in a night.

The stages of sleep are categorized into two major components. They are REM (rapid eye movement) and non-REM sleep. These various stages of sleep are only applicable to adults and older children. They do not apply to infants. Let’s look at the stages of non-REM sleep first.

Non–rapid-eye-movement stage 0: This stage is the prelude to sleep. A person becomes relaxed and closes their eyes.

Non–rapid-eye-movement stage 1 (NREM-1): In this stage, the person is still somewhat awake, or is lightly asleep and might toss and turn. The heart rate and body temperature drops and muscles relax. The person might also experience jerking movements and eyes may begin to roll, or they may even see bizarre images in the mind. In this stage, the brain produces high-amplitude theta waves.

Non–rapid-eye-movement stage 2 (NREM-2): This deeper stage of sleep lasts about 20 minutes. In this stage, a person experiences rapid brain activity and a decline in heart rate and respiration.
Non–rapid-eye-movement stage 3 (NREM-3): In this stage, the person is in a deep sleep that lasts for about 30 minutes. The person experiences slow breathing and pulse rates and limp muscles, and is difficult to wake. This stage is sometimes called delta sleep, because the brain produces slow delta waves.

Non–rapid-eye-movement stage 4 (NREM-4): In this stage, the person’s heart rate, respiration, temperature, and blood flow to the brain decrease. They are in the deepest level of sleep.

During stages 1 to 3, the person may have brief and fragmented dreams.

Rapid eye movement (REM): This is the last of the five stages of sleep. People spend approximately 20 percent of their overall sleep time in this stage and experience dreams. A person can be in this stage for 15 minutes to one hour.