I have always been fascinated by Dreams.Recently, doing a little personal research into the subject,I came across a few theories which every school of Oneirology agrees upon.
Activation Synthesis Theory:
In 1976 J. Allan Hobson and Robert McCarley proposed a new theory that changed dream research, challenging the previously held Freudian view of dreams as subconscious wishes to be interpreted. Activation synthesis theory asserts that the sensory experiences are fabricated by the cortex as a means of interpreting chaotic signals from the pons. They propose that in REM sleep, the ascending cholinergic PGO (ponto-geniculo- occipital) waves stimulate higher midbrain and forebrain cortical structures, producing rapid eye movements. The activated fore brain then synthesizes the dream out of this internally generated information. They assume that the same structures that induce REM sleep also generate sensory information.
Hobson's 1976 research suggested that the signals interpreted as dreams originated in the brain stem during REM sleep. However, research by Mark Solms suggests that dreams are generated in the forebrain, and that REM sleep and dreaming are not directly related. While working in the neurosurgery department at hospitals in Johannesburg and London , Solms had access to patients with various brain injuries. He began to question patients about their dreams and confirmed that patients with damage to the parietal lobe stopped dreaming; this finding was in line with Hobson's 1977 theory. However, Solms did not encounter cases of loss of dreaming with patients having brain stem damage. This observation forced him to question Hobson's prevailing theory which marked the brain stem as the source of the signals interpreted as dreams. Solms viewed the idea of dreaming as a function of many complex brain structures as validating Freudian dream theory, an idea that drew criticism from Hobson.
In 1978, Solms, along with partners William Kauffman and Edward Nadar, undertook a series of traumatic-injury impact studies using several different species of primates, particularly howler monkeys, in order to disprove Hobson's postulation that the brain stem played a significant role in dream pathology. Unfortunately, Solms' experiments proved inconclusive, as the high mortality rate associated with using an hydraulic impact pin to artificially induce brain damage in test subjects meant that his final candidate pool was too small to satisfy the requirements of the scientific method.
Continual Activation Theory:
Combining Hobson's activation synthesis hypothesis with Solms's findings, the continual-activatio n theory of dreaming presented by Jie Zhang proposes that dreaming is a result of brain activation and synthesis; at the same time, dreaming and REM sleep are controlled by different brain mechanisms. Zhang hypothesizes that the function of sleep is to process, encode and transfer the data from the temporary memory to the long-term memory, though there is not much evidence backing up this so-called "consolidation. " NREM sleep processes the conscious-related memory (declarative memory), and REM sleep processes the unconscious related memory (procedural memory).
Zhang assumes that during REM sleep, the unconscious part of a brain is busy processing the procedural memory; meanwhile, the level of activation in the conscious part of the brain will descend to a very low level as the inputs from the sensory are basically disconnected. This will trigger the "continual-activati on" mechanism to generate a data stream from the memory stores to flow through the conscious part of the brain. Zhang suggests that this pulse-like brain activation is the inducer of each dream. He proposes that, with the involvement of the brain associative thinking system, dreaming is, thereafter, self-maintained with the dreamer's own thinking until the next pulse of memory insertion. This explains why dreams have both characteristics of continuity (within a dream) and sudden changes (between two dreams).
Apparent Precognition:
According to surveys, it is common for people to feel that their dreams are predicting subsequent life events. Psychologists have explained these experiences in terms of memory biases, namely a selective memory for accurate predictions and distorted memory so that dreams are retrospectively fitted onto life experiences. The multi-faceted nature of dreams makes it easy to find connections between dream content and real events.In one experiment, subjects were asked to write down their dreams in a diary. This prevented the selective memory effect, and the dreams no longer seemed accurate about the future. Another experiment gave subjects a fake diary of a student with apparently precognitive dreams. This diary described events from the person's life, as well as some predictive dreams and some non-predictive dreams. When subjects were asked to recall the dreams they had read, they remembered more of the successful predictions than unsuccessful ones.
Dream Interpretation:
Dreams were historically used for healing (as in the asclepieions found in the ancient Greek temples of Asclepius) as well as for guidance or divine inspiration. Some Native American tribes used vision quests as a rite of passage, fasting and praying until an anticipated guiding dream was received, to be shared with the rest of the tribe upon their return.
During the late 19th and early 20th centuries, both Sigmund Freud and Carl Jung identified dreams as an interaction between the unconscious and the conscious. They also assert together that the 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.
Fritz Perls presented his theory of dreams as part of the holistic nature of Gestalt therapy. Dreams are seen as projections of parts of the self that have been ignored, rejected, or suppressed. Jung argued that one could consider every person in the dream to represent an aspect of the dreamer, which he called the subjective approach to dreams. Perls expanded this point of view to say that even inanimate objects in the dream may represent aspects of the dreamer. The dreamer may therefore be asked to imagine being an object in the dream and to describe it, in order to bring into awareness the characteristics of the object that correspond with the dreamer's personality.
Newer Insights:
In a paper published in October,2009, in the journal Nature Reviews Neuroscience, Dr. J. Allan Hobson, a psychiatrist and longtime sleep researcher at Harvard, argues that the main function of rapid-eye-movement sleep, or REM, when most dreaming occurs, is physiological. The brain is warming its circuits, anticipating the sights and sounds and emotions of waking.
"It helps explain a lot of things, like why people forget so many dreams," Dr. Hobson said in an interview. "It's like jogging; the body doesn't remember every step, but it knows it has exercised. It has been tuned up. It's the same idea here: dreams are tuning the mind for conscious awareness."
Drawing on work of his own and others, Dr. Hobson argues that dreaming is a parallel state of consciousness that is continually running but normally suppressed during waking. The idea is a prominent example of how neuroscience is altering assumptions about everyday (or every-night) brain functions.
"Most people who have studied dreams start out with some predetermined psychological ideas and try to make dreaming fit those," said Dr. Mark Mahowald, a neurologist who is director of the sleep disorders program at Hennepin County Medical Center , in Minneapolis . "What I like about this new paper is that he doesn't make any assumptions about what dreaming is doing."
The paper has already stirred controversy and discussion among Freudians, therapists and other researchers, including neuroscientists. Dr. Rodolfo Llinás, a neurologist and physiologist at New York University , called Dr. Hobson's reasoning impressive but said it was not the only physiological interpretation of dreams.
"I argue that dreaming is not a parallel state but that it is consciousness itself, in the absence of input from the senses," said Dr. Llinás, who makes the case in the book "I of the Vortex: From Neurons to Self" (M.I.T., 2001). Once people are awake, he argued, their brain essentially revises its dream images to match what it sees, hears and feels — the dreams are "corrected" by the senses.
These novel ideas about dreaming are based partly on basic findings about REM sleep. In evolutionary terms, REM appears to be a recent development; it is detectable in humans and other warm-blooded mammals and birds. And studies suggest that REM makes its appearance very early in life — in the third trimester for humans, well before a developing child has experience or imagery to fill out a dream.
In studies, scientists have found evidence that REM activity helps the brain build neural connections, particularly in its visual areas. The developing fetus may be "seeing" something, in terms of brain activity, long before the eyes ever open — the developing brain drawing on innate, biological models of space and time, like an internal virtual-reality machine. Full-on dreams, in the usual sense of the word, come much later. Their content, in this view, is a kind of crude test run for what the coming day may hold.None of this is to say that dreams are devoid of meaning. Anyone who can remember a vivid dream knows that at times the strange nighttime scenes reflect real hopes and anxieties: the young teacher who finds himself naked at the lectern; the new mother in front of an empty crib, frantic in her imagined loss.But people can read almost anything into the dreams that they remember, and they do exactly that. In a recent study of more than 1,000 people, researchers at Carnegie Mellon University and Harvard found strong biases in the interpretations of dreams. For instance, the participants tended to attach more significance to a negative dream if it was about someone they disliked, and more to a positive dream if it was about a friend.
In fact, research suggests that only about 20 percent of dreams contain people or places that the dreamer has encountered. Most images appear to be unique to a single dream.
Scientists know this because some people have the ability to watch their own dreams as observers, without waking up. This state of consciousness, called lucid dreaming, is itself something a mystery — and a staple of New Age and ancient mystics. But it is a real phenomenon, one in which Dr. Hobson finds strong support for his argument for dreams as a physiological warm-up before waking.
In dozens of studies, researchers have brought people into the laboratory and trained them to dream lucidly.They do this with a variety of techniques, including auto-suggestion as head meets pillow ("I will be aware when I dream; I will observe") and teaching telltale signs of dreaming (the light switches don't work; levitation is possible; it is often impossible to scream).
Lucid dreaming occurs during a mixed state of consciousness, sleep researchers say — a heavy dose of REM with a sprinkling of waking awareness. "This is just one kind of mixed state, but there are whole variety of them," Dr. Mahowald said. Sleepwalking and night terrors, he said, represent mixtures of muscle activation and non-REM sleep. Attacks of narcolepsy reflect an infringement of REM on normal daytime alertness.
In study published in September in the journal Sleep, Ursula Voss of J. W. Goethe-University in Frankfurt led a team that analyzed brain waves during REM sleep, waking and lucid dreaming. It found that lucid dreaming had elements of REM and of waking — most notably in the frontal areas of the brain, which are quiet during normal dreaming. Dr. Hobson was a co-author on the paper."You are seeing this split brain in action," he said. "This tells me that there are these two systems, and that in fact they can be running at the same time."
Researchers have a way to go before they can confirm or fill out this working hypothesis. But the payoffs could extend beyond a deeper understanding of the sleeping brain. People who struggle with schizophrenia suffer delusions of unknown origin. Dr. Hobson suggests that these flights of imagination may be related to an abnormal activation of a dreaming consciousness.
"Let the dreamer awake, and you will see psychosis," Jung said.
For everyone else, the idea of dreams as a kind of sound check for the brain may bring some comfort, as well.Whatever the Truth may be,I think we are all playwrites in our subconscious. .
Reference:
Nature Reviews Neuroscience
