Joe Lau

Out-of-body experiences

Readings

  • Tart, C. T. (1968). A psychophysiological study of out-of-the-body experiences in a selected subject. J Am Soc Psychical Res, 62: 3–27.
  • Blanke, et. el. (2002). Stimulating illusory own-body perceptions. Nature, 419, 269-70. doi:10.1038/419269a
  • Blanke, O., Landis, Spinelli, Seeck (2004). Out-of-body experience and autoscopy of neurological origin. Brain, 127, No. 2, 243-258. doi:10.1093/brain/awh040
  • Blanke et. el. (2005). Linking Out-of-Body Experience and Self Processing to Mental Own-Body Imagery at the Temporoparietal Junction. The Journal of Neuroscience, January 19, 2005, 25(3):550-557. doi:10.1523/JNEUROSCI.2612-04.2005
  • Bremmer The Rise and Fall of the Afterlife Routledge. Ch. 7 has a historical review of NDE.

Terminology

  • Out-of-body experience (OBE) = A subject seems to be awake and sees the world from a location outside the physical body.
  • Autoscopy (AS) = The experience of seeing one’s body in extrapersonal space.
  • Sample report:

@I was in bed and about to fall asleep when I had the distinct impression that I was at the ceiling level looking down at my body in the bed. I was very startled and frightened; immediately (afterwards) I felt that I was consciously back in the (body on the) bed again.@

Memory-based explanations

  • OBE a product of memory distortion during trauma (usually 3rd person perspective).

Body illusions

  • RubberHand

OBE induction

  • Ketamine (blockade of NDMA receptor) - short-acting, hallucinogenic anaesthetic. Some subjects report OBEs after falling into the "k-hole".
  • G-LOC (Gravity induced loss of conciousness) - Subjects losing conciousness because g-forces move the blood away from the brain (black out) or move excess blood towards the brain (red out). This typically happens to fighter pilots or astronauts.
  • See for example p59 of Susan Blackmore (1993). Dying to Live: Near-Death Experiences. Prometheus Books. isbn:0879758708
  • Blanke, et. el. (2002) - Electrical stimulation of the angular gyrus (an area on the surface of the brain close to the temporal lobe) of an epileptic patient.

@Initial stimulations (n = 3; 2.0−3.0 mA) induced vestibular responses, in which the patient reported that she was "sinking into the bed" or "falling from a height". Increasing the current amplitude (3.5 mA) led to an OBE ("I see myself lying in bed, from above, but I only see my legs and lower trunk"). ... The patient was then asked to watch her (real) legs during the electrical stimulation (n = 2; 4.0, 4.5 mA). ... This time, she reported seeing her legs "becoming shorter". If the patient's legs were bent before the stimulation (90° knee angle; n = 2; 4.0, 5.0 mA), she reported that her legs appeared to be moving quickly towards her face, and took evasive action.@

Physiological explanations of OBE

  • Cerebral Anoxia - Lack of oxygen in the brain, such as due to interuption in bloodflow in the G-LOC cases. But the following study shows that patients who survive cardiopulmonary resuscitation (CPR) are not particularly linked with NDE and OBE.
    • Pim van Lommel, Ruud van Wees, Vincent Meyers, Ingrid Elfferich (2001). Near-death experience in survivors of cardiac arrest: A prospective study in the Netherlands. The Lancet. London: Dec 15, 2001, 358, Iss. 9298, 2039-45.
  • Blanke:

@we speculate that ambiguous input from these different sensory systems is an important mechanism of OBE and AS, and thus the intriguing experience of seeing one’s body in a position that does not coincide with its felt position. We suggest that OBE and AS are related to a failure to integrate proprioceptive, tactile and visual information with respect to one’s own body (disintegration in personal space) and by a vestibular dysfunction leading to an additional disintegration between personal (vestibular) space and extrapersonal (visual) space. We argue that both disintegrations (personal; personal–extrapersonal) are necessary for the occurrence of OBE and AS, and that they are due to a paroxysmal cerebral dysfunction of the TPJ in a state of partially and briefly impaired consciousness.@

  • In Blanke et. el. (2005), TMS interference with temporoparietal junctions (TPJ) in normal subjects disrupts their imagination of OBE perspectives. Also, seizure in TPJ observed in epileptic patient who experiences OBE when imagining with OBE perspectives. TPJ is said to involve in understanding others' belief. See doi:10.1038/nn1223

Comments

  • If we discover that a paranormal experience P has some neural correlate N, it does not follow that P is illusory, e.g. having a perceptual experience as of a tree might correlate with a neural state but it does not follow that there is no tree being perceived.
  • However, extra evidence is then needed to support the conclusion that something else is going on - Ockham's razor / inference to the best explanation.

Two incompatible hypotheses:

  1. All OBE experiences are body image hallucinations.
  2. Some OBE experiences are veridical.

Test : Is it possible to obtain veridical information of the external environment during an OBE?

Inconclusive cases

@She was having surgery performed to remove an aneurism from her brain. Her body was cooled and blood was drained from her brain. Her EEG and brain stem response showed no activity, the definition of brain death in many states. She reported rising from her body and seeing the operation performed below her. She also reported contact with "The Light" and many of her deceased relatives. Upon recovering she recounted accurately many details of her operation, including conversations heard and a description of the surgical instruments.@

  • We have to deal with such cases carefully because it is often difficult to know what the real facts are. For example:

@A nurse at Hartford Hospital states that she worked with a patient described an NDE in which she saw a red shoe on the roof of the hospital during her OBE, which a janitor then retrieved. - Ring and Lawrence (1993). Further evidence for veridical perception during near-death experiences. Journal of Near-Death Studies, 11(4), 223-229.@

  • But according to others who visited the hospital, it is quite possible to see the shoe from within the hospital. See Ebbern et. el. (1996). Maria's near-death experience: waiting for the other shoe to drop. The Skeptical Inquirer, 20(4).

Category.Mind