Brain
activity shows basis of near-death experiences
Deccan
Chronicle - Tuesday, Aug 13, 2013 | Last Update : 06:43 PM
IST
Washington, District of Columbia, Aug 13:
There may be a scientific explanation for the vivid near-death
experiences, such as seeing a shining light, that some people
report after surviving a heart attack, US scientists said
Monday.
Apparently, the brain keeps on working for
up to 30 seconds after blood flow stops, according to a study
published in the Proceedings of the National Academy of
Sciences.
University of Michigan scientists did their
research on nine lab rats that were anesthetized and then subjected
to induced cardiac arrest as part of the
experiment.
In the first 30 seconds after their hearts
were stopped, they all showed a surge of brain activity, observed
in electroencephalograms (EEGs) that indicated highly aroused
mental states.
"We were surprised by the high levels of
activity," said senior author George Mashour, professor of
anesthesiology and neurosurgery at the University of
Michigan.
"In fact, at near-death, many known
electrical signatures of consciousness exceeded levels found in the
waking state, suggesting that the brain is capable of
well-organized electrical activity during the early stage of
clinical death."
Similar results in terms of brain activity
were seen in rats that were asphyxiated, the researchers
said.
"This study tells us that reduction of
oxygen or both oxygen and glucose during cardiac arrest can
stimulate brain activity that is characteristic of conscious
processing," said lead author Jimo Borjigin.
"It also provides the first scientific
framework for the near-death experiences reported by many cardiac
arrest survivors."
About 20 percent of people who survive
cardiac arrest report having had visions during a period known to
doctors as clinical death.
Borjigin said she hopes her team's latest
study "will form the foundation for future human studies
investigating mental experiences occurring in the dying brain,
including seeing light during cardiac arrest."
Mainstream science has long considered the
brain to be inactive during this period, and some experts
questioned how much a study on rats can truly reveal about the
human brain.
"Do we know if animals experience
'consciousness'? Most philosophers and scientists are still at
loggerheads over what the term refers to in humans, let alone in
other species," said David McGonigle, a lecturer at Cardiff
University.
"While recent research now suggests that
animals may indeed have the kind of autobiographical memories that
humans possess -- the kinds of memories that allow us to place
ourselves in a certain time and place -- it seems unlikely that
near death experiences would necessarily be similar across
species."
nders Sandberg, a research fellow at Oxford
University described the research as "simple" and "well-done," but
urged caution in interpreting the results.
"EEG tells us things about brain activity a
bit like listening at traffic noise tells you what is going on in a
city. It is certainly informative, but also an average of a lot of
individual interactions," he said.
"No doubt some people will presumptuously claim
that this is further evidence for life after death, which is doubly
silly. Near-death experiences are in themselves just experiences,"
he said. "But if one believes that, then one should also conclude
the afterlife includes a lot of lab
mice."
Is there life
after death? As a non-sectarian Buddhist myself, the answer is a
big ‘YES’ however doubly silly you may think it is Mr. Sandberg and
that includes lots of lab mice as well.