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Thursday, November 29, 2018

Homunculus

From Wikipedia, the free encyclopedia

A homunculus (/hˈmʌŋkjʊləs/; Latin for "little person") is a representation of a small human being. Popularized in sixteenth-century alchemy and nineteenth-century fiction, it has historically referred to the creation of a miniature, fully formed human. The concept has roots in preformationism as well as earlier folklore and alchemic traditions.

History

Alchemy

Astadi with the first mention of the homunculus in De homunculis (c. 1529–1532), and De natura rerum (1537).

The homunculus first appears by name in alchemical writings attributed to Paracelsus (1493–1541). De natura rerum (1537) outlines his method for creating homunculi:
That the sperm of a man be putrefied by itself in a sealed cucurbit for forty days with the highest degree of putrefaction in a horse's womb, or at least so long that it comes to life and moves itself, and stirs, which is easily observed. After this time, it will look somewhat like a man [sic], but transparent, without a body. If, after this, it be fed wisely with the Arcanum of human blood, and be nourished for up to forty weeks, and be kept in the even heat of the horse's womb, a living human child grows therefrom, with all its members like another child, which is born of a woman, but much smaller.
Comparisons have been made with several similar concepts in the writings of earlier alchemists. Although the actual word "homunculus" was never used, Carl Jung believed that the concept first appeared in the Visions of Zosimos, written in the third century AD. In the visions, Zosimos encounters a priest who changes into "the opposite of himself, into a mutilated anthroparion". The Greek word "anthroparion" is similar to "homunculus" – a diminutive form of "person". Zosimos subsequently encounters other anthroparion in his dream but there is no mention of the creation of artificial life. In his commentary, Jung equates the homunculus with the Philosopher's Stone, and the "inner person" in parallel with Christ.

In Islamic alchemy, Takwin (Arabic: تكوين‎) was a goal of certain Muslim alchemists, a notable one being Jābir ibn Hayyān. In the alchemical context, Takwin refers to the artificial creation of life in the laboratory, up to and including human life.

The homunculus continued to appear in alchemical writings after Paracelsus' time. The Chymical Wedding of Christian Rosenkreutz (1616) for example, concludes with the creation of a male and female form identified as Homunculi duo. The allegorical text suggests to the reader that the ultimate goal of alchemy is not chrysopoeia, but it is instead the artificial generation of humans. Here, the creation of homunculi symbolically represents spiritual regeneration and Christian soteriology.

In 1775, Count Johann Ferdinand von Kufstein, together with Abbé Geloni, an Italian cleric, are reputed to have created ten homunculi with the ability to foresee the future, which von Kufstein kept in glass containers at his Masonic lodge in Vienna. Dr. Emil Besetzny's Masonic handbook, Die Sphinx, devoted an entire chapter to the wahrsagenden Geister (scrying ghosts). These are reputed to have been seen by several people, including local dignitaries.

Folklore

References to the homunculus do not appear prior to sixteenth-century alchemical writings; however, alchemists may have been influenced by earlier folk traditions. The mandragora, known in German as Alreona, Alraun or Alraune is one example.

In Liber de imaginibus, Paracelsus however denies that roots shaped like men grow naturally. He attacks dishonest people who carve roots to look like men and sell them as Alraun. He clarifies that the homunculus’ origins are in sperm, and that it is falsely confused with these ideas from necromancy and natural philosophy.

The homunculus has also been compared to the golem of Jewish folklore. Though the specifics outlining the creation of the golem and homunculus are very different, the concepts both metaphorically relate man to the divine, in his construction of life in his own image.

Preformationism

A tiny person inside a sperm as drawn by Nicolaas Hartsoeker in 1695

Preformationism is the formerly-popular theory that animals developed from miniature versions of themselves. Sperm were believed to contain complete preformed individuals called "animalcules". Development was therefore a matter of enlarging this into a fully formed being. The term homunculus was later used in the discussion of conception and birth.

Nicolas Hartsoeker postulated the existence of animalcules in the semen of humans and other animals. This was the beginning of spermists' theory, who held the belief that the sperm was in fact a "little man" that was placed inside a woman for growth into a child. This seemed to them to neatly explain many of the mysteries of conception. It was later pointed out that if the sperm was a homunculus, identical in all but size to an adult, then the homunculus may have sperm of its own. This led to a reductio ad absurdum with a chain of homunculi "all the way down". This was not necessarily considered by spermists a fatal objection however, as it neatly explained how it was that "in Adam" all had sinned: the whole of humanity was already contained in his loins. The spermists' theory also failed to explain why children tend to resemble their mothers as well as their fathers, though some spermists believed that the growing homunculus assimilated maternal characteristics from the womb environment in which they grew.

Terminological use in modern science

The homunculus is commonly used today in scientific disciplines such as psychology as a teaching or memory tool to describe the distorted scale model of a human drawn or sculpted to reflect the relative space human body parts occupy on the somatosensory cortex (the "sensory homunculus") and the motor cortex (the "motor homunculus"). Both the motor and sensory homunculi usually appear as small men superimposed over the top of precentral or postcentral gyri for motor and sensory cortices, respectively. The homunculus is oriented with feet medial and shoulders lateral on top of both the precentral and the postcentral gyrus (for both motor and sensory). The man's head is depicted upside down in relation to the rest of the body such that the forehead is closest to the shoulders. The lips, hands, feet and sex organs have more sensory neurons than other parts of the body, so the homunculus has correspondingly large lips, hands, feet, and genitals. The motor homunculus is very similar to the sensory homunculus, but differs in several ways. Specifically, the motor homunculus has a portion for the tongue most lateral while the sensory homunculus has an area for genitalia most medial and an area for visceral organs most lateral. Well known in the field of neurology, this is also commonly called "the little man inside the brain." This scientific model is known as the cortical homunculus.
In medical science, the term homunculus is sometimes applied to certain fetus-like ovarian cystic teratomae. These will sometimes contain hair, sebaceous material and in some cases cartilagous or bony structures.

In popular culture

Early literature

19th-century engraving of Goethe's Faust and Homunculus

Homunculi can be found in centuries worth of literature. These fictions are primarily centred around imaginative speculations on the quest for artificial life associated with Paracelsian alchemy. One of the very earliest literary references occurs in Thomas Browne's Religio Medici (1643), in which the author states:
I am not of Paracelsus minde that boldly delivers a receipt to make a man without conjunction, ...
The fable of the alchemically-created homunculus may have been central in Mary Shelley's novel Frankenstein (1818). Professor Radu Florescu suggests that Johann Conrad Dippel, an alchemist born in Castle Frankenstein, might have been the inspiration for Victor Frankenstein. German playwright Johann Wolfgang von Goethe's Faust, Part Two (1832) famously features an alchemically-created homunculus. Here, the character of Homunculus embodies the quest of a pure spirit to be born into mortal form, contrasting Faust's desire to shed his mortal body to become pure spirit. The alchemical idea that the soul is not imprisoned in the body, but instead may find its brightest state as it passes through the material plane is central to the character. William Makepeace Thackeray wrote under the pen name of Homunculus.

Contemporary literature

The homunculus legend, Frankenstein and Faust have continued to influence works in the twentieth and twenty-first century. The theme has been used not only in fantasy literature, but also to illuminate social topics. For instance, the British children's writers Mary Norton and Rumer Godden used homunculus motifs in their work, expressing various post-war anxieties about refugees, persecution of minorities in war, and the adaptation of these minorities to a "big" world. W. Somerset Maugham's 1908 novel The Magician utilises the concept of the homunculus as an important plot element. David H. Keller’s short story "A Twentieth-Century Homunculus" (1930) describes the creation of homunculi on an industrial scale by a pair of misogynists. Likewise, Sven Delblanc’s The Homunculus: A Magic Tale (1965) addresses misogyny and the Cold War industrial-military complexes of the Soviet Union and NATO.

Other media

Homunculi appear in fantasy based television, film, and games in a manner consistent with literature. Examples can be found in numerous mediums, such as the films Homunculus (1916), Bride of Frankenstein (1935), The Golden Voyage of Sinbad (1973), the television movie Don't Be Afraid of the Dark (1973), Being John Malkovich (1999), Guillermo del Toro's The Devil's Backbone (2001), J.K. Rowling’s Fantastic Beasts: The Crimes of Grindelwald (2018), and the big-screen remake of Don't Be Afraid of the Dark (2011), fantasy role-playing games (such as Dungeons & Dragons), video games (such as Ragnarok Online, Valkyrie Profile, Shadow of Memories, The Legend of Heroes series, Cabals: Magic & Battle Cards), books (such as The Secret Series), graphic novels (such as Bureau for Paranormal Research and Defense) and manga (such as Homunculus, Fullmetal Alchemist, Fate/Zero, and Gosick).

Alice in Wonderland syndrome

From Wikipedia, the free encyclopedia

Alice in Wonderland syndrome
SynonymsTodd's syndrome, Lilliputian hallucinations, dysmetropsia
Illustration from Lewis Carroll's Alice's Adventures in Wonderland depicting the title character seated hunched over in a tiny room. Alice is positioned awkwardly with her weight supported partially by her left forearm, which rests on the floor and spans nearly half of the room's length. Her head is ducked beneath the low ceiling and her right arm reaches outside, resting on an open window's sill. The folds of Alice's dress occupy much of the remaining free space in the room.
The perception a person can have due to micropsia, a potential symptom of dysmetropsia. From Lewis Carroll's 1865 novel Alice's Adventures in Wonderland.
Classification and external resources
SpecialtyPsychiatry, neurology

Alice in Wonderland Syndrome (AiWS), also known as Todd's syndrome or dysmetropsia, is a disorienting neuropsychological condition that affects perception. People may experience distortions in visual perception such as micropsia (objects appearing small), macropsia (objects appearing large), pelopsia (objects appearing to be closer than they are), or teleopsia (objects appearing to be further away than they are). Size distortion may occur in other sensory modalities as well.

AiWS is often associated with migraines, brain tumors, and psychoactive drug use. It can also be the initial symptom of the Epstein–Barr Virus. AiWS can be caused by abnormal amounts of electrical activity resulting in abnormal blood flow in the parts of the brain that process visual perception and texture.

Anecdotal reports suggest that the symptoms are common in childhood, with many people growing out of it in their teen years. It appears that AiWS is also a common experience at sleep onset and has been known to commonly arise due to a lack of sleep.

Signs and symptoms

AiWS is often associated with migraines. AiWS affects the sense of vision, sensation, touch, and hearing, as well as one's own body image. Nausea, dizziness, and agitation are also commonly associated symptoms with Alice in Wonderland Syndrome.

Individuals with AiWS can experience hallucinations or illusions of expansion, reduction or distortion of their own body image, such as microsomatognosia (feeling that their own body or body parts are shrinking), or macrosomatognosia (feeling that their body or body parts are growing taller or larger). These changes in perception are collectively known as metamorphosias, or Lilliputian hallucinations.

People with certain neurological diseases have experienced similar visual hallucinations. These hallucinations are called "Lilliputian", which means that objects appear either smaller or larger than reality.

Patients may experience either micropsia or macropsia. Micropsia is an abnormal visual condition, usually occurring in the context of visual hallucination, in which the affected person sees objects as being smaller than they are in reality. Macropsia is a condition where the individual sees everything larger than it actually is.

One 17-year-old male described his odd symptoms by the following: "Quite suddenly objects appear small and distant or large and close. I feel as [if] I am getting shorter and smaller 'shrinking' and also the size of persons are not longer than my index finger (a lilliputian proportion). Sometimes I see the blind in the window or the television getting up and down, or my leg or arm is swinging. I may hear the voices of people quite loud and close or faint and far. Occasionally, I experience attacks of migrainous headache associated with eye redness, flashes of lights and a feeling of giddiness. I am always conscious to the intangible changes in myself and my environment".

Although a person's eyes are normal, they will often 'see' objects as the incorrect size, shape or perspective angle. Therefore, people, cars, buildings, houses, animals, trees, environments, etc., look smaller or larger than they should be. Further, depth perception can be altered whereby perceived distances are incorrect. For example, a corridor may appear to be very long, or the ground may appear too close.

Zoopsias is an additional hallucination that is sometimes associated with Alice in Wonderland Syndrome. Zoopsias involves hallucinations of either swarms of small animals (e.g. ants and mice etc.), or isolated groups of larger animals (e.g. dogs and elephants etc.). This experience of zoopsias is shared in a variety of conditions, such as delirium tremens.

The person affected by Alice in Wonderland syndrome may also lose a sense of time, a problem similar to the lack of spatial perspective. Time seems to pass very slowly, akin to an LSD experience. The lack of time and space perspective also leads to a distorted sense of velocity. For example, one could be inching along ever so slowly in reality, yet it would seem as if one were sprinting uncontrollably along a moving walkway, leading to severe, overwhelming disorientation.

Sufferers of Alice in Wonderland Syndrome can often experience paranoia as a result of disturbances in sound perception. This can include amplification of soft sounds or misinterpretation of common sounds.

In addition, some people may, in conjunction with a high fever, experience more intense and overt hallucinations, seeing things that are not there and misinterpreting events and situations. Less frequent symptoms sometimes described in Alice in Wonderland Syndrome patients include loss of limb control and dis-coordination, memory loss, lingering touch and sound sensations, and emotional instability.

It has been noted that patients are often reluctant to describe their symptoms due to fear of being labeled with a psychiatric disorder. It is usually easy to rule out psychosis as those with Alice in Wonderland Syndrome are typically aware that their hallucinations and distorted perceptions are not 'real', and they have not lost touch with reality. Furthermore, younger patients who frequently experience Alice in Wonderland syndrome may struggle to describe their unusual symptoms, and thus, it is recommended to encourage children to draw their visual illusions during episodes. It appears that the symptoms of AiWS do not change in severity over the course of the syndrome, and though the symptoms may acutely impact the patient's life, Alice in Wonderland syndrome typically resolves itself within weeks or months. Furthermore, AiWS symptoms occur transiently during the day for short periods of time, with most patients describing their symptoms as lasting anywhere between 10 seconds to 10 minutes. This, combined with the typically short duration of the syndrome, suggests that Alice in Wonderland Syndrome typically causes a relatively short-term disruption of normal functioning. However, symptoms can be debilitating when experienced, and the individual should exercise caution, for example when driving, as the symptoms can appear rapidly. Symptom severity influences whether or not the individual will be able to hold a job during these periods of misperception.

Genetic and environmental influences

While there currently is no identified genetic locus/loci associated with Alice in Wonderland Syndrome, observations suggest that a genetic component does exist. AiWS does appear to be passed on from parent to child, with one case study showcasing a grandmother, mother, son, and daughter all with Alice in Wonderland Syndrome. In addition, there is an established hereditary trait of migraines. Examples of environmental influences on the incidence of AiWS include the use of the drug topiramate and potentially the dietary intake of tyramine. Further research is required to establish the genetic and environmental influences on Alice in Wonderland Syndrome.

Alice in Wonderland

Alice in Wonderland Syndrome was named after Lewis Carroll's famous 19th-century novel Alice's Adventures in Wonderland. In the story, Alice, the title character, experiences numerous situations similar to those of micropsia and macropsia. The thorough descriptions of metamorphosis clearly described in the novel were the first of their kind to depict the bodily distortions associated with the condition. Speculation has arisen that Carroll may have written the story using his own direct experience with episodes of micropsia resulting from the numerous migraines he was known to suffer from. It has also been suggested that Carroll may have suffered from temporal lobe epilepsy.

Gulliver's Travels

Alice in Wonderland Syndrome's symptom of micropsia has also been related to Jonathan Swift's novel Gulliver's Travels. It has been referred to as "Lilliput sight" and "Lilliputian hallucination", a term coined by British physician Raoul Leroy in 1909, based on the small people that inhabited the island of Lilliput in the novel.

Etiology

Complete and partial forms of the Alice in Wonderland syndrome exist in a range of disorders, including epilepsy, intoxicants, infectious states, fevers, and brain lesions. Furthermore, the syndrome is commonly associated with migraines, as well as the use of psychoactive drugs. It can also be the initial symptom of the Epstein–Barr virus (see mononucleosis), and a relationship between the syndrome and mononucleosis has been suggested. Epstein-Barr Virus appears to be the most common cause in children, while for adults it is more commonly associated with migraines.

Cerebral hypotheses

AiWS can be caused by abnormal amounts of electrical activity causing abnormal blood flow in the parts of the brain that process visual perception and texture. Nuclear medical techniques using technetium, performed on patients during episodes of Alice in Wonderland syndrome, have demonstrated that AiWS is associated with reduced cerebral perfusion in various cortical regions (frontal, parietal, temporal and occipital), both in combination and in isolation. It has been hypothesized that any condition resulting in a decrease in perfusion of the visual pathways or visual control centers of the brain may be responsible for the syndrome. For example, one study used single photon emission computed tomography to demonstrate reduced cerebral perfusion in the temporal lobe in patients with AiWS. Other theories exist that suggest the syndrome is a result of unspecific cortical dysfunction (e.g. from encephalitis, epilepsy, decreased cerebral perfusion), or reduced blood flow to other areas of the brain. Other theories suggest that disordered body image perceptions stem from within the parietal lobe. This has been demonstrated by the production of disturbances of body image through electrical stimulation of the posterior parietal cortex. Other researchers suggest that metamorphopsias may be a result of reduced perfusion of the non-dominant posterior parietal lobe during migraine episodes.

Throughout all the neuroimaging studies, several cortical regions (including the temporoparietal junction within the parietal lobe, and the visual pathway, specifically the occipital lobe) are associated with the development of Alice in Wonderland syndrome symptoms.

Migraines

The role of migraines in Alice in Wonderland syndrome is still not understood, but both vascular and electrical theories have been suggested. For example, visual distortions may be a result of transient, localized ischaemia (an inadequate blood supply to an organ or part of the body) in areas of the visual pathway during migraine attacks. In addition, a spreading wave of depolarization of cells (particularly glial cells) in the cerebral cortex during migraine attacks can eventually activate the trigeminal nerve's regulation of the vascular system. The intense cranial pain during migraines is due to the connection of the trigeminal nerve with the thalamus and thalamic projections onto the sensory cortex. Alice in Wonderland syndrome symptoms can precede, accompany, or replace the typical migraine symptoms.

Diagnosis

Alice in Wonderland syndrome is a disturbance of perception rather than a specific physiological change to the body's systems. The diagnosis can be presumed when other causes have been ruled out and if the patient presents symptoms along with migraines and complains of onset during the day (although it can also occur at night). As there are no established diagnostic criteria for Alice in Wonderland syndrome, there is likely to be a large degree of variability in the diagnostic process and thus it is likely to be poorly diagnosed.

Prognosis

Whatever the cause, the bodily related distortions can recur several times a day and may take some time to abate. Understandably, the person can become alarmed, frightened, and panic-stricken throughout the course of the hallucinations—maybe even hurt themselves or others around them. The symptoms of the syndrome themselves are not harmful and are likely to disappear with time. The outcome is typically not harmful, especially in children, and most patients outgrow these episodes. The long-term prognosis typically depends on the root cause of the syndrome, and it is the underlying condition which must be evaluated and treated. Often, the difficulty lies within the patient's reluctance to describe their symptoms out of fear of being labeled with a psychiatric disorder.

Treatment

At present, Alice in Wonderland syndrome has no standardized treatment plan. Often, treatment methods revolve around migraine prophylaxis, as well as the promotion of a low tyramine diet. Drugs that may be used to prevent migraines include: anticonvulsants, antidepressants, calcium channel blockers, and beta blockers. Other treatments that have been explored include repetitive transcranial magnetic stimulation (rTMS). Further research is required to establish an effective treatment regime.

Epidemiology

The lack of established diagnostic criteria or large-scale epidemiological studies on Alice in Wonderland syndrome means that the exact prevalence of the syndrome is currently unknown. One study on 3,224 adolescents in Japan demonstrated the occurrence of macropsia and micropsia to be 6.5% in boys and 7.3% in girls, suggesting that the symptoms of AiWS may not be so rare.

It appears that the male/female ratio is dependent on the age range being observed. Studies showed that younger males (age range of 5 to 14 years) were 2.69 times more likely to experience AiWS than girls of the same age, while there were no significant differences between students of 13 to 15 years of age. Conversely, female students (16- to 18-year-olds) showed a significantly greater prevalence.

The average age of the start of Alice in Wonderland syndrome is six but it is very normal for some to experience the syndrome from childhood to their late 20's. It is also thought that this syndrome is hereditary because many parents who have AiWS report their children having it as well.

History

The syndrome is sometimes called Todd's syndrome, in reference to an influential description of the condition in 1955 by Dr. John Todd (1914-1987), a British Consultant Psychiatrist at High Royds Hospital at Menston in West Yorkshire. Todd discovered that several of his patients experienced severe headaches causing them to see and perceive objects as greatly out of proportion. They have altered sense of time and touch, as well as distorted perceptions of their own body. Although having migraine headaches, none of these patients had brain tumors, damaged eyesight, or mental illness that could have caused similar symptoms. They were also all able to think lucidly and could distinguish hallucinations from reality, however, their perceptions were skewed.

Since Lewis Carroll had been a well-known migraine sufferer with similar symptoms, Todd speculated that Carroll had used his own migraine experiences as a source of inspiration for his famous 1865 novel Alice’s Adventures in Wonderland. Carroll's diary reveals that in 1856 he consulted William Bowman, an eminent ophthalmologist, about the visual manifestations of the migraines he regularly experienced. Since Carroll had these migraine symptoms for years before writing Alice’s Adventures, it seemed reasonable that Carroll had used his experiences as inspiration.

Out-of-body experience

From Wikipedia, the free encyclopedia

Artist's depiction of the separation stage of an out-of-body experience, which often precedes free movement

An out-of-body experience (OBE or sometimes OOBE) is an experience in which a person seems to perceive the world from a location outside their physical body. An OBE is a form of autoscopy (literally "seeing self"), although the term autoscopy more commonly refers to the pathological condition of seeing a second self, or doppelgänger.

The term out-of-body experience was introduced in 1943 by G. N. M. Tyrrell in his book Apparitions, and was adopted by researchers such as Celia Green and Robert Monroe as an alternative to belief-centric labels such as "astral projection", "soul travel", or "spirit walking". OBEs can be induced by brain traumas, sensory deprivation, near-death experiences, dissociative and psychedelic drugs, dehydration, sleep, and electrical stimulation of the brain,[4] among others. It can also be deliberately induced by some. One in ten people have an OBE once, or more commonly, several times in their life.

Neuroscientists and psychologists regard OBEs as dissociative experiences arising from different psychological and neurological factors.

Spontaneous

During/near sleep

Those experiencing OBEs sometimes report (among other types of immediate and spontaneous experience) a preceding and initiating lucid-dream state. In many cases, people who claim to have had an OBE report being on the verge of sleep, or being already asleep shortly before the experience. A large percentage of these cases refer to situations where the sleep was not particularly deep (due to illness, noises in other rooms, emotional stress, exhaustion from overworking, frequent re-awakening, etc.). In most of these cases subjects perceive themselves as being awake; about half of them note a feeling of sleep paralysis.

Near-death experiences

Another form of spontaneous OBE is the near-death experience (NDE). Some subjects report having had an OBE at times of severe physical trauma such as near-drownings or major surgery. Near-death experiences may include subjective impressions of being outside the physical body, sometimes visions of deceased relatives and religious figures, and transcendence of ego and spatiotemporal boundaries. Typically the experience includes such factors as: a sense of being dead; a feeling of peace and painlessness; hearing of various non-physical sounds, an out-of-body experience; a tunnel experience (the sense of moving up or through a narrow passageway); encountering "beings of light" and a God-like figure or similar entities; being given a "life review", and a reluctance to return to life.

Resulting from extreme physical effort

Along the same lines as an NDE, extreme physical effort during activities such as high-altitude climbing and marathon running can induce OBEs. A sense of bilocation may be experienced, with both ground and air-based perspectives being experienced simultaneously.

Induced

Chemical

Mental induction

  • Falling asleep physically without losing awareness. The "Mind Awake, Body Asleep" state is widely suggested as a cause of OBEs, voluntary and otherwise. Thomas Edison used this state to tackle problems while working on his inventions. He would rest a silver dollar on his head while sitting with a metal bucket in a chair. As he drifted off, the coin would noisily fall into the bucket, restoring some of his alertness. OBE pioneer Sylvan Muldoon more simply used a forearm held perpendicular in bed as the falling object. Salvador Dalí was said to use a similar "paranoiac-critical" method to gain odd visions which inspired his paintings. Deliberately teetering between awake and asleep states is known to cause spontaneous trance episodes at the onset of sleep which are ultimately helpful when attempting to induce an OBE. By moving deeper and deeper into relaxation, one eventually encounters a "slipping" feeling if the mind is still alert. This slipping is reported to feel like leaving the physical body. Some consider progressive relaxation a passive form of sensory deprivation;
  • Deep trance, meditation and visualization. The types of visualizations vary; some common analogies include climbing a rope to "pull out" of one's body, floating out of one's body, getting shot out of a cannon, and other similar approaches. This technique is considered hard to use for people who cannot properly relax. One example of such a technique is the popular Golden Dawn "Body of Light" Technique.

Mechanical induction

  • Brainwave synchronization via audio/visual stimulation. Binaural beats can be used to induce specific brainwave frequencies, notably those predominant in various mind awake/body asleep states. Binaural induction of a "body asleep" 4 Hertz brainwave frequency was observed as effective by the Monroe Institute, and some authors consider binaural beats to be significantly supportive of OBE initiation when used in conjunction with other techniques. Simultaneous introduction of "mind awake" beta frequencies (detectable in the brains of normal, relaxed awakened individuals) was also observed as constructive. Another popular technology uses sinusoidal wave pulses to achieve similar results, and the drumming accompanying Native American religious ceremonies is also believed to have heightened receptivity to "other worlds" through brainwave entrainment mechanisms;
  • Magnetic stimulation of the brain, as with the God helmet developed by Michael Persinger;
  • Direct stimulation of the vestibular cortex;
  • Electrical stimulation of the brain, particularly the temporoparietal junction (see Blanke study below);
  • Sensory deprivation. This approach aims to induce intense disorientation by removal of space and time references. Flotation tanks or pink noise played through headphones are often employed for this purpose;
  • Sensory overload, the opposite of sensory deprivation. The subject can for instance be rocked for a long time in a specially designed cradle, or submitted to light forms of torture, to cause the brain to shut itself off from all sensory input. Both conditions tend to cause confusion and this disorientation often permits the subject to experience vivid, ethereal out-of-body experiences;
  • Strong g-forces that causes blood to drain from parts of the brain, as experienced for example in high-performance aircraft or high-G training for pilots and astronauts;
  • An apparatus that uses a head-mounted display and a touch that confuses the sense of proprioception (and which can also create the sensation of additional limbs).

Theories of OBEs

Psychological

In the fields of cognitive science and psychology OBEs are considered dissociative experiences arising from different psychological and neurological factors. Scientists consider the OBE to be an experience from a mental state, like a dream or an altered state of consciousness without recourse to the paranormal.

Charles Richet (1887) held that OBEs are created by the subject's memory and imagination processes and are no different from dreams. James H. Hyslop (1912) wrote that OBEs occur when the activity of the subconscious mind dramatizes certain images to give the impression the subject is in a different physical location. Eugéne Osty (1930) considered OBEs to be nothing more than the product of imagination. Other early researchers (such as Schmeing, 1938) supported psychophysiological theories. G. N. M. Tyrrell interpreted OBEs as hallucinatory constructs relating to subconscious levels of personality.

Donovan Rawcliffe (1959) connected the OBE experience with psychosis and hysteria. Other researchers have discussed the phenomena of the OBE in terms of a distortion of the body image (Horowitz, 1970) and depersonalization (Whitlock, 1978).[49][50] The psychologists Nandor Fodor (1959) and Jan Ehrenwald (1974) proposed that an OBE is a defense mechanism designed to deal with the threat of death. According to (Irin and Watt, 2007) Jan Ehrenwald had described the out-of-body experience (OBE) "as an imaginal confirmation of the question for immortality, a delusory attempt to assure ourselves that we possess a soul that exists independently of the physical body. The psychologists Donald Hebb (1960) and Cyril Burt (1968) wrote on the psychological interpretation of the OBE involving body image and visual imagery. Graham Reed (1974) suggested that the OBE is a stress reaction to a painful situation, such as the loss of love. John Palmer (1978) wrote that the OBE is a response to a body image change causing a threat to personal identity.

Carl Sagan (1977) and Barbara Honegger (1983) wrote that the OBE experience may be based on a rebirth fantasy or reliving of the birth process based on reports of tunnel-like passageways and a cord-like connection by some OBErs which they compared to an umbilical cord. Susan Blackmore (1978) came to the conclusion that the OBE is a hallucinatory fantasy as it has the characteristics of imaginary perceptions, perceptual distortions and fantasy-like perceptions of the self (such as having no body). Ronald Siegel (1980) also wrote that OBEs are hallucinatory fantasies.

Harvey Irwin (1985) presented a theory of the OBE involving attentional cognitive processes and somatic sensory activity. His theory involved a cognitive personality construct known as psychological absorption and gave instances of the classification of an OBE as examples of autoscopy, depersonalization and mental dissociation. The psychophysiologist Stephen Laberge (1985) has written that the explanation for OBEs can be found in lucid dreaming. David Hufford (1989) linked the OBE experience with a phenomenon he described as a nightmare waking experience, a type of sleep paralysis. Other scientists have also linked OBEs to cases of hypnagogia and sleep paralysis (cataplexy).

In case studies fantasy proneness has been shown to be higher among OBErs than those who have not had an OBE. The data has shown a link between the OBE experience in some cases to fantasy prone personality (FPP). In a case study involving 167 participants the findings revealed that those who claimed to have experienced the OBE were "more fantasy prone, higher in their belief in the paranormal and displayed greater somatoform dissociation." Research from studies has also suggested that OBEs are related to cognitive-perceptual schizotypy.

Terence Hines (2003) has written that spontaneous out-of-body experiences can be generated by artificial stimulation of the brain and this strongly suggests that the OBE experience is caused from "temporary, minor brain malfunctions, not by the person's spirit (or whatever) actually leaving the body." In a study review of neurological and neurocognitive data (Bünning and Blanke, 2005) wrote that OBEs are due to "functional disintegration of lower-level multisensory processing and abnormal higher-level self-processing at the temporoparietal junction." Some scientists suspect that OBEs are the result of a mismatch between visual and tactile signals.

Richard Wiseman (2011) has noted that OBE research has focused on finding a psychological explanation and "out-of-body experiences are not paranormal and do not provide evidence for the soul. Instead, they reveal something far more remarkable about the everyday workings of your brain and body." A study conducted by Jason Braithwaite and colleagues (2011) linked the OBE to "neural instabilities in the brain's temporal lobes and to errors in the body's sense of itself". Braithwaite et al. (2013) reported that the "current and dominant view is that the OBE occurs due to a temporary disruption in multi-sensory integration processes."

Paranormal

Writers within the fields of parapsychology and occultism have written that OBEs are not psychological and that a soul, spirit or subtle body can detach itself out of the body and visit distant locations. Out-of-the-body experiences were known during the Victorian period in spiritualist literature as "travelling clairvoyance". The psychical researcher Frederic Myers referred to the OBE as a "psychical excursion". An early study which described alleged cases of OBEs was the two volume Phantasms of the Living, published in 1886 by the psychical researchers Edmund Gurney, Myers and Frank Podmore. The book was largely criticized by the scientific community as the anecdotal reports lacked evidential substantiation in nearly every case.

A 19th-century illustration of Robert Blair's poem The Grave, depicting the soul leaving the body

The Theosophist Arthur Powell (1927) was an early author to advocate the subtle body theory of OBEs. Sylvan Muldoon (1936) embraced the concept of an etheric body to explain the OBE experience. The psychical researcher Ernesto Bozzano (1938) had also supported a similar view describing the phenomena of the OBE experience in terms of bilocation in which an "etheric body" can release itself from the physical body in rare circumstances. The subtle body theory was also supported by occult writers such as Ralph Shirley (1938), Benjamin Walker (1977) and Douglas Baker (1979). James Baker (1954) wrote that a mental body enters an "intercosmic region" during the OBE. Marilynn Hughes states that the experiences are the projection of the spiritual body from the physical for the purpose of the soul's purification. Robert Crookall in many publications supported the subtle body theory of OBEs.

The paranormal interpretation of OBEs has not been supported by all researchers within the study of parapsychology. Gardner Murphy (1961) wrote that OBEs are "not very far from the known terrain of general psychology, which we are beginning to understand more and more without recourse to the paranormal".

In the 1970s, Karlis Osis conducted many OBE experiments with the psychic Alex Tanous. For a series of these experiments he was asked whilst in an OBE state to try to identify coloured targets that were placed in remote locations. Osis reported that in 197 trials there were 114 hits. However, the controls to the experiments have been criticized and according to Susan Blackmore, the final result was not particularly significant as 108 hits would be expected by chance. Blackmore noted that the results provide "no evidence for accurate perception in the OBE".

In April 1977, a patient from Harborview Medical Center known as Maria claimed to have experienced an out-of-body experience. During her OBE she claimed to have floated outside her body and outside of the hospital. Maria would later tell her social worker Kimberly Clark that during the OBE she had observed a tennis shoe on the third floor window ledge to the north side of the building. Clark would go to the north wing of the building and by looking out of the window could see a tennis shoe on one of the ledges. Clark published the account in 1985. The story has since been used in many paranormal books as evidence a spirit can leave the body.

In 1996, Hayden Ebbern, Sean Mulligan and Barry Beyerstein visited the Medical Center to investigate the story. They placed a tennis shoe on the same ledge and discovered that the shoe was visible from within the building and could have easily been observed by a patient lying in bed. They also discovered the shoe was easily observable from outside the building and suggested that Maria may have overheard a comment about it during her three days in the hospital and incorporated it into her OBE. They concluded "Maria's story merely reveals the naiveté and the power of wishful thinking" from OBE researchers seeking a paranormal explanation. Clark did not publish the description of the case until seven years after it happened, casting doubt on the story. Richard Wiseman has said that although the story is not evidence for anything paranormal it has been "endlessly repeated by writers who either couldn't be bothered to check the facts, or were unwilling to present their readers with the more skeptical side of the story."

Studies of OBEs

Early collections of OBE cases had been made by Ernesto Bozzano (Italy) and Robert Crookall (UK). Crookall approached the subject from a spiritualistic position, and collected his cases predominantly from spiritualist newspapers such as the Psychic News, which appears to have biased his results in various ways. For example, the majority of his subjects reported seeing a cord connecting the physical body and its observing counterpart; whereas Green found that less than 4% of her subjects noticed anything of this sort, and some 80% reported feeling they were a "disembodied consciousness", with no external body at all.

The first extensive scientific study of OBEs was made by Celia Green (1968). She collected written, first-hand accounts from a total of 400 subjects, recruited by means of appeals in the mainstream media, and followed up by questionnaires. Her purpose was to provide a taxonomy of the different types of OBE, viewed simply as an anomalous perceptual experience or hallucination, while leaving open the question of whether some of the cases might incorporate information derived by extrasensory perception.

In 1999, at the 1st International Forum of Consciousness Research in Barcelona, International Academy of Consciousness research-practitioners Wagner Alegretti and Nanci Trivellato presented preliminary findings of an online survey on the out-of-body experience answered by internet users interested in the subject; therefore, not a sample representative of the general population.

1,007 (85%) of the first 1,185 respondents reported having had an OBE. 37% claimed to have had between two and ten OBEs. 5.5% claimed more than 100 such experiences. 45% of those who reported an OBE said they successfully induced at least one OBE by using a specific technique. 62% of participants claiming to have had an OBE also reported having enjoyed nonphysical flight; 40% reported experiencing the phenomenon of self-bilocation (i.e. seeing one's own physical body whilst outside the body); and 38% claimed having experienced self-permeability (passing through physical objects such as walls). The most commonly reported sensations experienced in connection with the OBE were falling, floating, repercussions e.g. myoclonia (the jerking of limbs, jerking awake), sinking, torpidity (numbness), intracranial sounds, tingling, clairvoyance, oscillation and serenity.

Another reported common sensation related to OBE was temporary or projective catalepsy, a more common feature of sleep paralysis. The sleep paralysis and OBE correlation was later corroborated by the Out-of-Body Experience and Arousal study published in Neurology by Kevin Nelson and his colleagues from the University of Kentucky in 2007. The study discovered that people who have out-of-body experiences are more likely to suffer from sleep paralysis.

Also noteworthy, is the Waterloo Unusual Sleep Experiences Questionnaire  that further illustrates the correlation. William Buhlman, an author on the subject, has conducted an informal but informative online survey.

In surveys, as many as 85% of respondents tell of hearing loud noises, known as "exploding head syndrome" (EHS), during the onset of OBEs.

Miss Z study

In 1968, Charles Tart conducted an OBE experiment with a subject known as Miss Z for four nights in his sleep laboratory. The subject was attached to an EEG machine and a five-digit code was placed on a shelf above her bed. She did not claim to see the number on the first three nights but on fourth gave the number correctly. The psychologist James Alcock criticized the experiment for inadequate controls and questioned why the subject was not visually monitored by a video camera. Martin Gardner has written the experiment was not evidence for an OBE and suggested that whilst Tart was "snoring behind the window, Miss Z simply stood up in bed, without detaching the electrodes, and peeked." Susan Blackmore wrote "If Miss Z had tried to climb up, the brain-wave record would have showed a pattern of interference. And that was exactly what it did show."

Neurology and OBE-like experiences

There are several possible physiological explanations for parts of the OBE. OBE-like experiences have been induced by stimulation of the brain. OBE-like experience has also been induced through stimulation of the posterior part of the right superior temporal gyrus in a patient. Positron-emission tomography was also used in this study to identify brain regions affected by this stimulation. The term OBE-like is used above because the experiences described in these experiments either lacked some of the clarity or details of normal OBEs, or were described by subjects who had never experienced an OBE before. Such subjects were therefore not qualified to make claims about the authenticity of the experimentally-induced OBE.

British psychologist Susan Blackmore and others suggest that an OBE begins when a person loses contact with sensory input from the body while remaining conscious. The person retains the illusion of having a body, but that perception is no longer derived from the senses. The perceived world may resemble the world he or she generally inhabits while awake, but this perception does not come from the senses either. The vivid body and world is made by our brain's ability to create fully convincing realms, even in the absence of sensory information. This process is witnessed by each of us every night in our dreams, though OBEs are claimed to be far more vivid than even a lucid dream.

Irwin pointed out that OBEs appear to occur under conditions of either very high or very low arousal. For example, Green found that three quarters of a group of 176 subjects reporting a single OBE were lying down at the time of the experience, and of these 12% considered they had been asleep when it started. By contrast, a substantial minority of her cases occurred under conditions of maximum arousal, such as a rock-climbing fall, a traffic accident, or childbirth. McCreery has suggested that this paradox may be explained by reference to the fact that sleep can supervene as a reaction to extreme stress or hyper-arousal. He proposes that OBEs under both conditions, relaxation and hyper-arousal, represent a form of "waking dream", or the intrusion of Stage 1 sleep processes into waking consciousness.

Olaf Blanke studies

Research by Olaf Blanke in Switzerland found that it is possible to reliably elicit experiences somewhat similar to the OBE by stimulating regions of the brain called the right temporal-parietal junction (TPJ; a region where the temporal lobe and parietal lobe of the brain come together). Blanke and his collaborators in Switzerland have explored the neural basis of OBEs by showing that they are reliably associated with lesions in the right TPJ region and that they can be reliably elicited with electrical stimulation of this region in a patient with epilepsy. These elicited experiences may include perceptions of transformations of the patient's arms and legs (complex somatosensory responses) and whole-body displacements (vestibular responses).

In neurologically normal subjects, Blanke and colleagues then showed that the conscious experience of the self and body being in the same location depends on multisensory integration in the TPJ. Using event-related potentials, Blanke and colleagues showed the selective activation of the TPJ 330–400 ms after stimulus onset when healthy volunteers imagined themselves in the position and visual perspective that generally are reported by people experiencing spontaneous OBEs. Transcranial magnetic stimulation in the same subjects impaired mental transformation of the participant's own body. No such effects were found with stimulation of another site or for imagined spatial transformations of external objects, suggesting the selective implication of the TPJ in mental imagery of one's own body.

In a follow up study, Arzy et al. showed that the location and timing of brain activation depended on whether mental imagery is performed with mentally embodied or disembodied self location. When subjects performed mental imagery with an embodied location, there was increased activation of a region called the "extrastriate body area" (EBA), but when subjects performed mental imagery with a disembodied location, as reported in OBEs, there was increased activation in the region of the TPJ. This leads Arzy et al. to argue that "these data show that distributed brain activity at the EBA and TPJ as well as their timing are crucial for the coding of the self as embodied and as spatially situated within the human body."

Blanke and colleagues thus propose that the right temporal-parietal junction is important for the sense of spatial location of the self, and that when these normal processes go awry, an OBE arises.

In August 2007 Blanke's lab published research in Science demonstrating that conflicting visual-somatosensory input in virtual reality could disrupt the spatial unity between the self and the body. During multisensory conflict, participants felt as if a virtual body seen in front of them was their own body and mislocalized themselves toward the virtual body, to a position outside their bodily borders. This indicates that spatial unity and bodily self-consciousness can be studied experimentally and is based on multisensory and cognitive processing of bodily information.

Ehrsson study

In August 2007, Henrik Ehrsson, then at the Institute of Neurology at University College of London (now at the Karolinska Institute in Sweden), published research in Science demonstrating the first experimental method that, according to the scientist's claims in the publication, induced an out-of-body experience in healthy participants. The experiment was conducted in the following way:
The study participant sits in a chair wearing a pair of head-mounted video displays. These have two small screens over each eye, which show a live film recorded by two video cameras placed beside each other two metres behind the participant's head. The image from the left video camera is presented on the left-eye display and the image from the right camera on the right-eye display. The participant sees these as one "stereoscopic" (3D) image, so they see their own back displayed from the perspective of someone sitting behind them.

The researcher then stands just beside the participant (in their view) and uses two plastic rods to simultaneously touch the participant's actual chest out-of-view and the chest of the illusory body, moving this second rod towards where the illusory chest would be located, just below the camera's view.

The participants confirmed that they had experienced sitting behind their physical body and looking at it from that location.
Both critics and the experimenter himself note that the study fell short of replicating "full-blown" OBEs. As with previous experiments which induced sensations of floating outside of the body, Ehrsson's work does not explain how a brain malfunction might cause an OBE. Essentially, Ehrsson created an illusion that fits a definition of an OBE in which "a person who is awake sees his or her body from a location outside the physical body."

Awareness during Resuscitation Study

In 2001, Sam Parnia and colleagues investigated out of body claims by placing figures on suspended boards facing the ceiling, not visible from the floor. Parnia wrote "anybody who claimed to have left their body and be near the ceiling during resuscitation attempts would be expected to identify those targets. If, however, such perceptions are psychological, then one would obviously not expect the targets to be identified." The philosopher Keith Augustine, who examined Parnia's study, has written that all target identification experiments have produced negative results. Psychologist Chris French wrote regarding the study "unfortunately, and somewhat atypically, none of the survivors in this sample experienced an OBE."

In the autumn of 2008, 25 UK and US hospitals began participation in a study, coordinated by Sam Parnia and Southampton University known as the AWARE study (AWAreness during REsuscitation). Following on from the work of Pim van Lommel in the Netherlands, the study aims to examine near-death experiences in 1,500 cardiac arrest survivors and so determine whether people without a heartbeat or brain activity can have documentable out-of-body experiences. As part of the study Parnia and colleagues have investigated out of body claims by using hidden targets placed on shelves that could only be seen from above. Parnia has written "if no one sees the pictures, it shows these experiences are illusions or false memories".

In 2014 Parnia issued a statement indicating that the first phase of the project has been completed and the results are undergoing peer review for publication in a medical journal. No subjects saw the images mounted out of sight according to Parnia's early report of the results of the study at an American Heart Association meeting in November 2013. Only two out of the 152 patients reported any visual experiences, and one of them described events that could be verified. The two NDEs occurred in an area were "no visual targets had been placed".

On October 6, 2014, the results of the study were published in the journal Resuscitation. Among those who reported a perception of awareness and completed further interviews, 46 per cent experienced a broad range of mental recollections in relation to death that were not compatible with the commonly used term of NDEs. These included fearful and persecutory experiences. Only 9 per cent had experiences compatible with NDEs and 2 per cent exhibited full awareness compatible with OBEs with explicit recall of 'seeing' and 'hearing' events. One case was validated and timed using auditory stimuli during cardiac arrest. According to Caroline Watt "The one 'verifiable period of conscious awareness' that Parnia was able to report did not relate to this objective test. Rather, it was a patient giving a supposedly accurate report of events during his resuscitation. He didn't identify the pictures, he described the defibrillator machine noise. But that's not very impressive since many people know what goes on in an emergency room setting from seeing recreations on television."

AWARE Study II

As of May 2016, a posting at the UK Clinical Trials Gateway website describes plans for AWARE II, a two-year multicenter observational study of 900-1500 patients experiencing cardiac arrest, with subjects being recruited as August 1, 2014 and a trial end date of May 31, 2017.

Smith & Messier

A recent functional imaging study reported the case of a woman who could experience out of body experience at will. She reported developing the ability as a child and associated it with difficulties in falling sleep. Her OBEs continued into adulthood but became less frequent. She was able to see herself rotating in the air above her body, lying flat, and rolling in the horizontal plane. She reported sometimes watching herself move from above but remained aware of her unmoving "real" body. The participant reported no particular emotions linked to the experience. "[T]he brain functional changes associated with the reported extra-corporeal experience (ECE) were different than those observed in motor imagery. Activations were mainly left-sided and involved the left supplementary motor area and supramarginal and posterior superior temporal gyri, the last two overlapping with the temporal parietal junction that has been associated with out-of-body experiences. The cerebellum also showed activation that is consistent with the participant's report of the impression of movement during the ECE. There was also left middle and superior orbital frontal gyri activity, regions often associated with action monitoring."

OBE training and research facilities

The Monroe Institute's Nancy Penn Center is a facility specializing in or out-of-body experience induction. The Center for Higher Studies of the Consciousness in Brazil is another large OBE training facility. The International Academy of Consciousness in southern Portugal features the Projectarium, a spherical structure dedicated exclusively for practice and research on out-of-body experience. Olaf Blanke's Laboratory of Cognitive Neuroscience has become a well-known laboratory for OBE research.

Astral projection

Astral projection is a paranormal interpretation of out-of-body experiences that assumes the existence of one or more non-physical planes of existence and an associated body beyond the physical. Commonly such planes are called astral, etheric, or spiritual. Astral projection is often experienced as the spirit or astral body leaving the physical body to travel in the spirit world or astral plane.

Computer-aided software engineering

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