Near-death experiences are
'electrical surge in dying
brain' By Rebecca Morelle Science reporter, BBC World
Service 13 August 2013


Near-death survivors have
reported seeing bright white
lights and having out-of-body
experiences A surge of electrical activity in
the brain could be responsible
for the vivid experiences
described by near-death
survivors, scientists report.
A study carried out on dying
rats found high levels of
brainwaves at the point of the
animals' demise. US researchers said that in
humans this could give rise to a
heightened state of
consciousness. The lead author of the study, Dr
Jimo Borjigin, of the University
of Michigan, said: "A lot of
people thought that the brain
after clinical death was
inactive or hypoactive, with less activity than the waking
state, and we show that is
definitely not the case. "If anything, it is much more
active during the dying process
than even the waking state." Consciousness From bright white lights to out-
of-body sensations and
feelings of life flashing before
their eyes, the experiences
reported by people who have
come close to death but survived are common the world
over. However, studying this in
humans is a challenge, and
these visions are little
understood. To find out more, scientists at
the University of Michigan
monitored nine rats as they
were dying. In the 30-second period after
the animal's hearts stopped
beating, they measured a sharp
increase in high-frequency
brainwaves called gamma
oscillations. These pulses are one of the
neuronal features that are
thought to underpin
consciousness in humans,
especially when they help to
"link" information from different parts of the brain. In the rats, these electrical
pulses were found at even
higher levels just after the
cardiac arrest than when
animals were awake and well. Dr Borjigin said it was feasible
that the same thing would
happen in the human brain,
and that an elevated level of
brain activity and
consciousness could give rise to near-death visions. Neurons in the brain may go
into overdrive around the point
of death "This can give us a framework
to begin to explain these. She said. "We have seen increased
coupling between the lower-
frequency waves and the
gamma that has been shown to
be a feature of visual
awareness and visual sensation." However, she said that to
confirm the findings a study
would have to be carried out on
humans who have experienced
clinical death and have been
revived. Commenting on the research,
Dr Jason Braithwaite, of the
University of Birmingham, said
the phenomenon appeared to
be the brain's "last hurrah". "This is a very neat
demonstration of an idea
that's been around for a long
time: that under certain
unfamiliar and confusing
circumstances - like near-death - the brain becomes
overstimulated and
hyperexcited," he said. Striking "Like 'fire raging through the
brain', activity can surge
through brain areas involved in
conscious experience,
furnishing all resultant
perceptions with realer-than- real feelings and emotions." But he added: "One limitation
is that we do not know when,
in time, the near-death
experience really occurs.
Perhaps it was before patients
had anaesthesia, or at some safe point during an operation
long before cardiac arrest. "However, for those instances
where experiences may occur
around the time of cardiac
arrest - or beyond it - these
new findings provide further
meat to the bones of the idea that the brain drives these
fascinating and striking
experiences" Dr Chris Chambers, of Cardiff
University, said: "This is an
interesting and well-conducted
piece of research. We know
precious little about brain
activity during death, let alone conscious brain activity. These
findings open the door to
further studies in humans. "[But] we should be extremely
cautious before drawing any
conclusions about human near-
death experiences: it is one
thing to measure brain activity
in rats during cardiac arrest, and quite another to relate
that to human experience."