(1979). james baker (1954) wrote that a mental body enters an "intercosmic region" during the obe. robert crookall supported the subtle body theory of obes in several publications. 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. in one series of these experiments, he was asked whilst in an obe state whether he could identify coloured targets that were placed in remote locations. osis reported that there were 114 hits in 197 trials. however, the controls for the experiments have been criticized and, according to susan blackmore, the final result was not particularly significant since 108 hits would have been expected by chance alone. 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 the hospital. maria later told 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 then went 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 1984. the story has since been used in many paranormal books as evidence that a spirit can leave the body. in 1996, hayden ebbern, sean mulligan and barry beyerstein visited the medical center to investigate clark's story. they placed a tennis shoe on the same ledge and found that it was visible from within the building and could easily have been observed by a patient lying in bed. they also discovered that the tennis shoe was easy to observe from outside the building and suggested that maria may have overheard a comment about it during her three days in the hospital and then 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." clark responded to the accusations made in a separate paper. 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. obe studies 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 (see below) 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. international academy of consciousness - global survey in 1999, at the 1st international forum of consciousness research in barcelona, 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 experience sleep paralysis. also noteworthy, is the waterloo unusual sleep experiences questionnaire that further illustrates the correlation. 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 the 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 temporoparietal junction (tpj; a region where the temporal lobe and the 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