Q: What are dreams and their purpose? - Layperson

A: To grasp the answer one must first understand sleep. In 1953, Eugene Aserinsky of the University of Chicago noticed that the eyes of sleeping babies moved beneath their eyelids at certain regular intervals. This led to the discovery of REM (Rapid Eye Movement) sleep periods, which occur at roughly 60-90 minute intervals throughout the night and which contain the dreams which are the most vivid and most often remembered. Since then, EEG (electroencephalogram) recordings, which monitor brain activity during sleep, have been used to map the various stages of sleep. These states are classified roughly into sleep onset (hypnagogia or stage 1), non-REM sleep (deep sleep or stages 2, 3, and 4), and REM (or paradoxical) sleep.

There are five distinct sleep stages that can be measured by polysomnography: rapid eye movement (REM) sleep and four stages of non-rapid eye movement (NREM) sleep states 1, 2, 3, and 4.) Stage 1 NREM sleep is a transition from wakefulness to sleep and occupies about 5% of time spent asleep in healthy adults. Stage 2 NREM sleep, which is characterized by specific EEG waveforms (sleep spindles and K complexes), occupies about 50% of time spent asleep. Stages 3 and 4 NREM sleep (slow-wave sleep) are the deepest levels of sleep and occupy about 10%-20% of sleep time. REM sleep, during which the majority of typical story-like dreams occur, occupies about 20%-25% of total sleep.

These sleep stages have a characteristic temporal organization across the night. NREM stages 3 and 4 tend to occur in the first one-third to one-half of the night and increase in duration in response to sleep deprivation. REM sleep occurs cyclically throughout the night, alternating with NREM sleep about every 80-100 minutes. REM sleep periods increase in duration toward the morning. Human sleep also varies characteristically across the life span. After relative stability with large amounts of slow-wave sleep in childhood and early adolescence, sleep continuity and depth deteriorate across the adult age range. This deterioration is reflected by increased wakefulness and stage 1 sleep and decreased stages 3 and 4 sleep.

Polysomnography is the monitoring of multiple electrophysiological parameters during sleep and generally includes measurement of EEG activity, electrooculographic activity, and electromyographic activity. Additional polysomnographic measure may include oral or nasal airflow, respiratory effort, chest and abdominal wall movement, oxyhemoglobin saturation, or exhaled carbon dioxide concentration; these measures are used to monitor respiration during sleep and to detect the presence and severity of sleep apnea. Measurement of peripheral electromyographic activity may be used to detect abnormal movement during sleep. Most polysomnographic studies are conducted during the person's usual sleeping hours-that is, at night. However, daytime polysomnographic studies also are used to quantify daytime sleepiness.

Most dreams occur in the REM stage, although they can and do occur at any stage. Dreams are the mind's way of determining future possibilities. There are generally considered to be three levels of state of mind, although different names may be used for the different levels by different authorities. They are as follows - subconscious, conscious, and superconscious. The subconscious level stores all past information gathered by the physical and spiritual senses and filters out what is necessary to the conscious level or present level. The present or conscious level determines the best possibilities to take to get to the superconscious level or future. Dreams are the mind's outlet to do this in the safest manner possible, much like different computer programs to determine the outcomes of car crash tests without smashing a car or maiming actual human occupants. Any number of factors can play into a dream depending on the upbringing and background of the person doing the dreaming. The outcomes can be quite accurate. Many creative minds including artists, musicians, scientists and so on, have been provided solutions that had taken many months or even years of laborious research without end only to fall asleep and dream about it.

Dreams usually fall into one of the categories below, although this list is not all inclusive:

LUCID DREAMS	A Dream in which you know that you are dreaming is called a 'lucid dream'. It generally happens when you realize during the course of a dream that you are dreaming, perhaps because something strange or unexpected occurs. These types of dreams may reveal personal information as you observe the development of the dream through the expression of your feelings while being aware that you are dreaming. A lucid dream may develop directly or indirectly into an OBE. Sometimes during lucid dreaming we loose concentration for a brief period of time.
ORDINARY DREAMS	They are created by ourselves as the reality we want. Dream reality is removed from physical reality as a prearranged series of events in which we play a role. It's like being an actor in a movie. However, there are different variations of ordinary or common dreams which differ due to personal desires or influential substances within the body. For example, if we are using a prescribed drug or medicine due to a certain illness, this might have certain side effects which the body is not accustomed to and when we dream, it may change the entire meaning of an experience. Other ordinary dreams are influenced due to our individual personality or desires.
NIGHTMARES	Although a nightmare might shake us up, they should not be taken literally, as they may only be warning for a potential event. However, nightmares may also occur due to a preoccupation with solving a problem or if experiencing the side effects of a medicine we are taking. Certain foods can also trigger nightmares. Some bad experiences we had in the past could also be recalled by our subconscious mind in the present through nightmares. Nightmares are very different from reincarnation dreams that contain negative experiences.
SPIRIT GUIDE DREAMS	When we are having an ordinary dream and some of the characters protect us, we are being contacted by our Spirit Guides. Protection may take shape through a helping hand or communication. The Entities in these dreams are in fact our Spirit Guides, which we all have throughout our lifetimes. When communication takes place we don't feel scared or shy as subconsciously we know them from other realities. These dreams differ from mediumship because they start and end as ordinary dreams, and in between we are introduced to Entities wishing to communicate.
UNIVERSAL ARCHETYPE DREAMS	Since we all belong to the same Origin, a person may have the same dream as another due to the Universal Consciousness we all share.
ASTRAL PROJECTION OR O.B.E.	When the Astral Body separates itself from the physical self and travels to a particular place or event, the experience is referred to as an Out of Body Experience. OBEs are of many types, such as Interdimensional projection, NDEs and others.
PSYCHIC DREAMS	Prophetic dreams or Veridical dreams - these dreams have a definite impact on us as we remember them quite vividly. They represent future events that are being foreseen or foretold.
	Telepathic dreams - the dreamer receives information from another person, either living or dead, but pertaining to the present. The message may come from a distance.
	Reincarnation dreams or past life dreams are dreams in which an individual sees himself/herself going through actions or places with which he or she is not familiar in present existence. These dreams differ from mystical experiences as they are normally in black and white. Mystical experiences of past lifetimes are a form of OBE and may be triggered through a form of trance or hypnotic regression. What we experience is very real.
	Clairvoyant dreams - these dreams allows the dreamer to perceive things beyond the natural range of senses which trigger extrasensory perception (ESP). In other words the dream creates a keen intuitive understanding of places or events related or unrelated to the person.

Dreams also allow the body to physically repair itself and some say for the spirit side of us to travel to other dimensions, distances, realities, and so on.