FOR millennia out of body experiences have been seized on as evidence of an afterlife or proof that humans have a soul which leaves their body after death.
But neuroscientists are increasingly unravelling the brain malfunctions that trigger these mysterious and sometimes disturbing phenomena, with laboratory experiments showing that they can be simulated using virtual reality – and may even offer a breakthrough solution for chronic pain.
Dr Jane Aspell, an associate professor of cognitive neuroscience who is due to present the latest findings of her own research at the upcoming British Science Festival, said one of the first things to understand is that despite their common association with operating tables, near fatal heart attacks, and ‘bright lights and tunnels’ they often have nothing to do with near-death events.
“One of the most common causes of an OBE [out-of-body experience] is epilepsy,” said Dr Aspell.
“They can also be caused by migraines, tumours, brain injuries, and they can even happen in healthy people – particularly in traumatic situations, like a traumatic childbirth or a road crash. Very strong fatigue can also cause it.”
In 2004, a woman who was conscious with part of her skull removed while surgeons attached electrodes to her brain in preparation for a procedure to treat her epilepsy spontaneously experienced an OBE, telling medics she could see herself and them “from above”.
“She wasn’t really above herself,” said Dr Aspell. “It’s a hallucination created by the brain, and it was triggered by stimulation of this particular brain area.”
The region concerned is the temporoparietal junction (TPJ), a nexus which processes sensory information such as sight and touch to create a feeling of the ‘self’ being located within the body.
If its normal function is disrupted, however – for example by a seizure or a reduction in blood flow during a heart attack – the TPJ “generates an experience of the self that is very bizarre”, says Dr Aspell.
“The self then appears to be located outside of your body.”
Although most people associate OBEs with a sensation of ‘floating’ and ‘looking down’, there are other forms.
In auto-scopic hallucination, a person who is standing or seated when their TPJ begins misfiring will see their double appear next to them.
A third, sometimes terrifying, form of the phenomena is heautoscopy. In this, the sufferer also hallucinates a doppelganger self before a sudden “switch” leaves them feeling as if their self is inside their double’s body instead. Some sufferers even experience a confusing sensation that they have two selves in two locations simultaneously.
“This is really distressing because people then question ‘which self is me?’, and find this really horrifying,” said Dr Aspell.
“There was a case study of a woman in her 40s where it was caused by epilepsy. She found it awful and intolerable and tried to commit suicide, but in this case report the researchers asked her whenever she saw her double to raise her hand.
“What they found when they observed her brainwaves on the ECG was that they looked normal, but when a seizure happened the brain activity went crazy, like an earthquake, and from the moment the seizure began she raised her hand. That shows the connection between the seizure and the hallucination.
“She’d had it for years but luckily after they gave her different epilepsy medication it seemed to get rid of the symptoms.”
Although fascinating in their own right, OBEs are also shedding light on how the brain constructs its sense of ‘self’ as well as potential therapeutic uses.
One experiment Dr Aspell has been carrying out in her lab at Anglia Ruskin University uses virtual reality to mimic heautoscopy.
In it, participants don a virtual reality headset which is linked up to a webcam positioned exactly two metres behind them, giving the illusion that they are standing behind themselves.
A researcher who is also in the room then taps the participant on the back, leaving the participant’s brain flummoxed by contradictory senses of sight and touch.
“You’re feeling these taps on yourself, but you’re seeing them on the body in front of you,” said Dr Aspell.
“This starts to induce an illusion – not in everyone, but some people experience it very strongly – that the virtual body in front of you is the real you and that your self is not located in your own body.”
While some people are “freaked out” by the experience, when the study is repeated on volunteers with autism – whose brains process the ‘self’ differently – they do not experience the illusion at all.
OBEs are also seen as a coping mechanism for trauma, allowing a person to dissociate mentally from a traumatic situation.
This inspired Dr Aspell to explore whether they might be useful in treating chronic pain – with intriguing results.
“We tested this illusion, which only lasts two minutes, on people with lots of chronic pain conditions, and we found a 40% reduction in the pain rate before and after, which is a really good analgesic response.
“We’re doing a funded study now into patients with [nerve pain condition] fibromyalgia.”
The British Science Festival is taking place from September 7 to 11.