Introduction to dreaming



A dream is the experience of images, sounds/voices, words, thoughts or sensations during sleep, with the dreamer usually unable to influence the experience. Dreams are full of (mental) imagery. This imagery ranges from the banal to the surreal; in fact, dreams often provoke artistic and other forms of inspiration. Forms of dreams include the frightening or upsetting nightmare, and erotic dreams with sexual images, erection in males, and nocturnal emission.

The meaning of dreams has interested humanity throughout history. The scientific discipline of dream research is oneirology; dreams have been understood physiologically as a response to stimuli during sleep, psychologically as reflections of the unconscious, and spiritually as messages from God or predictions of the future (oneiromancy).

Most scientists believe that dreams occur in all humans with about equal frequency per amount of sleep; what varies is the ability to recall what is dreamed. Dreaming in animals (discussed below) varies from species to species.

Neurology of dreams
There are many competing theories as to the neurological cause of the dreaming experience. It is not clear in what phase of sleep dreaming takes place, where in the brain dreams originate &mdash; if there is such a single location, or even why dreams occur at all.

Dreaming has been associated with rapid eye movement (REM) sleep, a lighter form of sleep that occurs during the latter portion of the sleep cycle. REM sleep is characterized by rapid horizontal eye movements, stimulation of the pons, increased respiratory and heart rate, and temporary paralysis of the body. The nature of the relationship remains an open question, as research has shown that slow-wave sleep impedes dream recall. By way of comparison, dreams (in men) are associated with penis erection about as frequently as with REM sleep.

In line with the theory of REM sleep, the activation synthesis theory developed by Allan Hobson and Robert McCarley states that the brain tries to interpret random impulses from the pons as sensory input. Memory, attention and the other features lacking in a dream state depend on the lack of norepinephrine and serotonin, producing a psychotic state, as well as a lack of orientation in time, place and person.

On the other hand, research by Mark Solms suggests that dreams are generated in the forebrain, and that REM sleep and dreaming are two different brain systems.

Eugen Tarnow suggests that dreams are everpresent excitations of the long term memory system, even during waking life &mdash; McCarley also observes that when asked to recall their last thought, subjects often reported somewhat hallucinatory thoughts. The strangeness of dreams is then due to long-term memories being stored in "dream format"; this is reminiscent of the Penfield &amp; Rasmussen’s findings that electrical excitations of the cortex give rise to experiences similar to dreams. During waking life an executive function interprets long term memory consistent with reality checking.

Supernatural interpretations of dreams

 * Main article: Oneiromancy

The mysterious and often bizarre nature of dreams has led many to interpret dreams as divine gifts or messages, as predictions of the future, or as messages from the past. Alternatively, the idea of the "dream world" as real and the "day world" as imagine is another supernatural interpretation of dreams. Profound dreams believed to be sent by God have led to conversion to another religion.

Oneiromancy, prediction of the future through the interpretation of dreams, holds great credence in ancient Judeo-Christianity: in the Tanakh, Jacob, Joseph and Daniel are given the ability to interpret dreams by Yahweh; in the New Testament, divine inspiration comes as a dream to Saint Joseph, the husband of Mary.

Western philosophers of a skeptical bent (notably René Descartes) have pointed out that dream experiences are indistinguishable from "real" events from the viewpoint of the dreamer, and so no objective basis exists for determining whether one is dreaming or awake at any given instant. One must, they argue, accept the reality of the waking world on the basis of faith.

Psychodynamic interpretation of dreams

 * Main article: Dream interpretation

Both Sigmund Freud and Carl Jung identify dreams as an interaction between the unconscious and the conscious. They also assert together that unconscious is the dominant force of the dream, and in dreams it conveys its own mental activity to the perceptive faculty. While Freud felt that there was an active censorship against the unconscious even during sleep, Jung argued that the dream's bizarre quality is an efficient language, comparable to poetry and uniquely capable of revealing the underlying meaning.

Lucid dreaming

 * Main article: Lucid dreaming

A lucid dreamer recognizes the dream state and can assume control of the dream. This control is particularly helpful during nightmares, when the "dream self" can face the "attacker" or other source of anxiety to confront or destroy it. Additionally, the lucid dreamers have free reign to make new objects appear, change form, or fly. Lucid dreams can occur spontaneously, especially during youth, but frequent lucid dreaming requires dedication and practice; lucid dreamers pracitice the technique for personal or spiritual gain.

Lucid dreams can be categorized into dream-initiated lucid dreams (DILDs) and wake-initiated lucid dreams (WILDs). DILDs start as non-lucid dreams, but at some point in the dream the dreamer recognizes the experience as a dream. In a WILD, conscious logic and reasoning is preserved while the dreamer transitions from waking to dreaming, and the dreamer is lucid from the beginning of the dream. A common DILD technique, mnemonic induction of lucid dreams (MILD), was developed by Stephen LaBerge; it uses mnemonics to recognize the dream-state.

Dreaming in animals
For a long time true dreaming had only been positively confirmed in humans, but recently there have been research reports supporting a view that dreaming occurs in other animals as well. Animals certainly undergo REM sleep, but their subjective experience is difficult to determine. The animal with the longest average periods of REM sleep is the armadillo. It would appear that mammals and birds are the only, or at least most frequent, dreamers in nature, which is perhaps related to their sleep patterns. Many animals such as frogs probably do not sleep at all (except when hibernating, which is a different kind of state).

Some researchers have managed to block the brain mechanism that paralyzes the body during dreaming. With this method it has been discovered that a cat seems to dream mostly about chasing prey and playing with it. On a more basic level, many dog owners have also noted that their pets sometimes move their legs as if running or even make weak barking noises while asleep, or that their pets suddenly wake up and appear to think that a character from a nightmare is actually real.