The Trigger of Brain Stimulation:
Dr. Bruce Greyson's NDE Research
say they have triggered
(OBEs) in a female patient
by stimulating her brain. They believe their work may help
to explain mysterious incidents when people report experiences
of "leaving" their body and watching it from above. The
doctors did not set out to achieve the effect - they were
actually treating the women for epilepsy. Neurologist Professor
Dr. Olaf Blanke
and colleagues at
University Hospitals of Geneva
in Switzerland were using electrodes to stimulate
the brain. They found that stimulating one spot - the
in the right cortex - repeatedly caused out-of-body experiences
the stimulations caused the woman to feel she was "sinking"
into the bed, or falling from a height. When the current
amplitude was increased, she reported leaving her body.
She told the doctors, "I see myself lying in bed, from above,
but I only see my legs and lower trunk." Further stimulations
led to a feeling of lightness and "floating" close to the
ceiling. The patient was then asked to watch her real legs
as current was passed through the electrodes attached to
her head. This time she reported her legs "becoming shorter".
If bent, her legs appeared to be moving quickly towards
her face, causing her to take evasive action. A similar
effect happened when she was asked to look at her outstretched
arms. The left arm appeared shortened, but the right arm
was unaffected. If both arms were bent by 90 degrees at
the elbow, the woman felt her left lower arm and hand were
moving towards her face.
believe the angular gyrus plays an important role in matching
up visual information and the brain's touch and balance
representation of the body. When the two become dissociated,
an out-body-experience may result. Writing in the journal
Nature, the Swiss team said out-of-body experiences tended
to be short-lived, and to disappear when a person attempts
to inspect the illusory body or body part. Professor Blanke
believes that out-of-body sensations may be caused by an
overactive angular gyrus. Alternatively, the electrical
stimulation might actually have depressed activity in the
it was impossible to rule out possibility that other areas
of the brain were also involved. He said there was no evidence
to suggest that out-of-body experiences were linked to epilepsy.
He states, "OBEs have been reported in neurological patients
with epilepsy, migraine and after cerebral strokes, but
they also appear in healthy subjects. Awareness of a biological
basis of OBEs might allow some patients who suffer frequently
from OBEs to talk about them more openly. In addition, physicians
might take the phenomenon more seriously and carry out necessary
investigations such as an EEG, MRI, and neurological examinations."
However, researchers say that
results do not entirely explain these strange reports -
nor do reductionist arguments
fully explain them. Neurologist
Dr. Bruce Greyson
of the University of Virginia said the experiment does not
necessarily prove that all OBEs are illusions. He said it
is possible that some OBEs occur in different ways than
the scientists suspect.
"We cannot assume from the fact
that electrical stimulation of the brain can induce OBE-like
illusions that all OBEs are therefore illusions," replied
University of Virginia neurologist Dr. Bruce Greyson.
Blanke concedes, "We do not fully understand the neurological
mechanism that causes OBEs."
researchers mapped the brain activity of a 43-year old woman
who had been experiencing seizures for 11 years. They implanted
electrodes to stimulate portions of her brain's right temporal
lobe. The temporal lobe, which includes the angular gyrus
structure, is associated with perception of sound, touch,
memory and speech. Dr. Blanke suspects that the right angular
gyrus integrates signals from the visual system, as well
as information on touch and balance.
of people have reported OBEs, but relatively few have been
In 2001, the British medical journal
Lancet published a Dutch study
in which 344 cardiac patients were resuscitated from clinical
death. About 12 percent reported out-of-body experiences,
seeing light at the end of a tunnel, and speaking to dead