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
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
Initially, 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.
The doctors 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-of-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
He said 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."
results do not entirely explain these strange
nor do reductionist
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
"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.
Dr. Blanke concedes,
"We do not fully understand the neurological
mechanism that causes OBEs."
The Swiss 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.
Millions of people
have reported OBEs, but relatively few have
been clinically analyzed.
In 2001, the British
Lancet published a
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 relatives.