May 24, 2019 • 13 mins
Today it is generally agreed that absolute death for humans comes only when the brain has irreversibly ceased to function.
However, a remarkable paper authored by a team of neuroscientist from Yale School of Medicine and published in April 2019, has reignited the debate over just what is and what isn’t irreversible.
Could what appears to be a dead brain, in fact still remain one with potential to regain consciousness?
Go to @unexplainedpod, facebook.com/unexplainedpodcast or unexplainedpodcast.com for more info. Thank you for listening.
However, a remarkable paper authored by a team of neuroscientist from Yale School of Medicine and published in April 2019, has reignited the debate over just what is and what isn’t irreversible.
Could what appears to be a dead brain, in fact still remain one with potential to regain consciousness?
Go to @unexplainedpod, facebook.com/unexplainedpodcast or unexplainedpodcast.com for more info. Thank you for listening.
See omnystudio.com/listener for privacy information.
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:10):
Welcome to Unexplained Extra with me Richard McClane Smith, where
for the weeks in between episodes, we look at stories
and ideas that, for one reason another didn't make it
into the previous show. In last week's episode, Death's Pale Flag,
we explored the Haitian zombie myth through the seemingly miraculous
story of Clavius Narcis. In nineteen sixty four, Clavius was
(00:34):
declared dead by two separate doctors and subsequently buried underground,
only to reappear in his home village eighteen years later
very much alive. Some, thanks to the prevalence of the
zombie myth in Haitian folklore, were convinced that Clavius had
himself returned from death as a zombie. In nineteen eighty two,
(00:58):
ethnobotanist Weighed Dave traveled to Haiti to investigate Clerviius's story.
As it turned out, according to Davis, Clerviius was just
one of many individuals who would have fallen victim to
an apparent zombification process being carried out by voodoo priests
in return for money. After analyzing a powder thought to
(01:19):
have been used in this process, Wade found it to
contain traces of tetrodotoxin, a potent neurotoxin extracted from pufferfish.
Although even a small dose of tetrodotoxin is lethal to humans,
with just the right amount, its effects, including severe paralysis
and the slowing of the body's metabolic rate, can lead
(01:40):
the recipient appearing clinically dead before they eventually recover from it.
Could this thought Wade account for Clerviius's apparent resurrection, regardless
of what exactly had happened. That Clerviius could ever have
been declared dead in the first place raises a deeply
un settling question. Just how exactly do we determine whether
(02:04):
somebody has well and truly died. It may be surprising
to discover that it isn't by any stretch an exact science.
In years gone by, the death of a human individual
was believed to have occurred simply when breathing had stopped
(02:26):
or the heart was no longer beating. More recently, we
have come to understand that absolute death comes only when
the brain has irreversibly ceased to function. However, it wasn't
until nineteen sixty eight that a definition of brain death
previously referred to as irreversible coma, was first formalized according
(02:50):
to the Harvard Medical School Committee that to find it.
The process for confirming brain death is fourfold. First, the
body's responsiveness is taken into consideration, whether even the most
painful stimuli failed to elicit a reaction. Next, the body
is monitored for signs of spontaneous movement and breathing. Does
(03:12):
it require a ventilator to remain alive, for example. Thirdly,
the body's reflexes will be assessed, most commonly by examining
whether pupils respond to light or whether they are fixed
and dilated. Finally, having taken all of that into account,
an electroencephalogram or EEG should be used to test for
(03:35):
any sign of brain activity. Only after all the correct
criteria have been met could an individual be determined to
have well and truly died. Although this definition has been
refined somewhat since nineteen sixty eight, with today's modern fMRI
scanners a far more sophisticated way to measure brain activity,
(03:56):
the basic process for determining the death of an individual
remains more or less the same. And yet, just as
we used to think that a stopped heart or final
breath was evidence of death. Might it also be the
case that the criteria for supposed brain death could also
one day prove to be an inadequate measure of a
(04:18):
complete demise. Perhaps, just like in the days before we
were able to measure brain activity, there might yet be
some future more sophisticated technology to reveal the horrifying truth
that brain death is in fact not a permanent, irreversible state.
Could what appears to be a dead brain in fact
(04:40):
still remain one with the potential to regain consciousness? Are
you always taking care of your family? Do you often
take care of others and not yourself? Now it's time
to take care of yourself, to make time for you
you deserve it. Tell a DOC gives you access to
a licensed therapist to help you get back to feeling
(05:02):
your best, to feeling like yourself again. With TELEDOC, you
can speak to a licensed therapist by phone or video.
Therapy appointments are available seven days a week from seven
am to nine pm local time. If you feel overwhelmed
sometimes maybe you feel stressed or anxious, depressed or lonely,
or you might be struggling with a personal or family
(05:25):
issue teledoc can help. Teledoc is committed to facilitating great
therapeutic matches, so they make it easy to change counselors
if needed. For free teledoc therapy is available through most
insurance or employers. Download the app or visit teledoc dot
com forward slash Unexplained podcast today to get started. That's
(05:47):
teladoc dot com slash Unexplained podcast. In early twenty nineteen,
a team of neuroscientists from Yale School of Medicine, led
by its Vonomere vi Celia and Stefano Danielli, published a
remarkable paper in Nature which, although not providing proof by
(06:09):
any stretch that an individual might recover consciousness from a
supposed brain death, has nonetheless reignited the debate over just
what is or isn't irreversible. It is well understood that
reducing oxygen and blood flow to the brain can have
rapid and devastating consequences. Just a few seconds without oxygen
(06:30):
will result in a loss of consciousness. After five minutes
a dino scene, triphosphate or atyp the body's primary source
of cellular energy, will run out. If perfusion, the flow
of blood and oxygen is not restored, a progressive and
largely irreversible spiral of mechanical failure ensues from the build
(06:53):
up of carbon dioxide to the emergence of enzymes that
begin to break down the nerve tissue, which will lead
inevitably to the death of the brain. Although in the past,
individual cells taken from brains long after death have been
shown to continue to function, performing processes such as making proteins.
(07:14):
What Vesselia and Danielli's team wanted to know was could
a whole brain be revived a number of hours after death.
To test this out, researchers collected thirty two severed heads
of pigs that had been slaughtered in an abatoir close
to the team's laboratory. The brains, having been removed from
(07:36):
the skulls, were then placed in a chamber and fitted
with catheters. After waiting four hours from the moment of decapitation,
each brain was given an EEG to confirm a flat
line of brain activity before a warm substance containing nutrients
and oxygen was slowly pumped into them. The system, known
(07:57):
as brain X, developed especially for the experiment, is essentially
a brain specific dialysis machine designed to mimic the original
host's blood flow. Although they didn't expect the brains to
regain consciousness, the team used a chemical agent in the
solution to reduce the possibility of this happening. With the
(08:17):
solution cycling through the brains, all the scientists had to
do next was stand back and wait. After six hours
of tests, the results were startling. As an experiment to
test the efficacy of the brain X system, things could
not have gone better, as almost complete circulation was restored
(08:39):
to the brains. Blood vessels remained in such good shape
throughout the experiment that they continued to function in the
manner of a living brain. The system also succeeded in
preserving the global structure of the brain. Tissue areas that
are particularly susceptible to a lack of oxygen include the hippocampus,
(09:01):
which plays a vital role in the consolidation of memories,
were also well preserved. Comparing the solution as it flowed
to and from the brains. Research has also discovered signs
of metabolic activity as individual cells began to function again,
generating carbon dioxide while absorbing glucose and oxygen. But most
(09:24):
striking of all, when small slices of tissue were tested
after treatment, the team discovered that at least some neurons
remained capable of neural activity, a process thought fundamental for
generating consciousness. As the team from Yale were keen to stress,
(09:48):
their findings did not signify a resurgence of normal brain function. However,
as others, including science journalist Sarah Reardon and the brain
X team themselves have pointed out, since significant measures were
taken to prevent this from happening, there is no knowing
as yet what might have occurred under different circumstances, and
(10:10):
even if the brain EX system was not enough to
resurrect a consciousness from a dead brain, it would not
be the end of the road for such a pursuit.
It may be the case that some additional, as yet
unknown action might be needed to kick start this into life.
After all, only in nineteen forty seven, thanks to the
(10:30):
Maverick instincts of cardiac surgeon Claude Beck, was it confirmed
that an electrical shock could restart a human heart. Certainly,
it remains to be seen if an individual's sense of
consciousness could be restored after their brain has been declared
clinically dead by today's standards. However, if history is anything
(10:51):
to go by, that we haven't discovered yet how this
might be achieved is no indication that it cannot be done,
And with this comes some unsettling ideas just how much
of a brain is required, or more specifically, how many
of its constituent parts are necessary for a sense of
(11:12):
consciousness and self awareness to emerge, even if we think
not enough sections have been reactivated for this to occur.
Might the brain be able to construct modes of conscious
self awareness that we are not yet aware of and
therefore wouldn't even know if they had been activated or not.
And if, by some miracle it were possible to restore
(11:35):
a sense of self awareness in a previously dead brain,
whose self awareness would it be the individual that existed
before death or something else, perhaps before we dismiss entirely
the more alarming possibilities, As pointed out by the authors
of a recent Comet piece about the remarkable brain X experiment,
(11:57):
we might do well to ponder the wise word sub
miracle Max from the nineteen eighty seven film The Princess Bride.
There's a big difference between mostly dead and all dead.
Mostly dead is also slightly alive. If you enjoy listening
(12:20):
to Unexplained and would like to help support us, you
can now go to Unexplained podcast dot com, Forward slash Support.
All donations, no matter how large or small, are massively appreciated.
All elements of Unexplained are produced by me, Richard McClain smith.
Please subscribe and rate the show on iTunes, and feel
(12:42):
free to get in touch with any thoughts or ideas
regarding the stories you've heard on the show. Perhaps you
have an explanation of your own you'd like to share.
You can reach us online at Unexplained podcast dot com,
or Twitter at Unexplained Pod and Facebook at Facebook dot com.
Forward Slash Unexplained Now, it's time to take care of yourself.
(13:10):
To make time for you, teledoc gives you access to
a licensed therapist to help you get back to feeling
your best. Speak to a licensed therapist by phone or
video anytime between seven am to nine pm local time,
seven days a week. Teledoc Therapy is available through most
insurance or employers. Download the app or visit teledoc dot com,
(13:34):
Forward Slash Unexplained Podcast Today to get started. That's t
e ladoc dot com, slash Unexplained podcast
Welcome to Unexplained Extra with me Richard McClane Smith, where
for the weeks in between episodes, we look at stories
and ideas that, for one reason another didn't make it
into the previous show. In last week's episode, Death's Pale Flag,
we explored the Haitian zombie myth through the seemingly miraculous
story of Clavius Narcis. In nineteen sixty four, Clavius was
(00:34):
declared dead by two separate doctors and subsequently buried underground,
only to reappear in his home village eighteen years later
very much alive. Some, thanks to the prevalence of the
zombie myth in Haitian folklore, were convinced that Clavius had
himself returned from death as a zombie. In nineteen eighty two,
(00:58):
ethnobotanist Weighed Dave traveled to Haiti to investigate Clerviius's story.
As it turned out, according to Davis, Clerviius was just
one of many individuals who would have fallen victim to
an apparent zombification process being carried out by voodoo priests
in return for money. After analyzing a powder thought to
(01:19):
have been used in this process, Wade found it to
contain traces of tetrodotoxin, a potent neurotoxin extracted from pufferfish.
Although even a small dose of tetrodotoxin is lethal to humans,
with just the right amount, its effects, including severe paralysis
and the slowing of the body's metabolic rate, can lead
(01:40):
the recipient appearing clinically dead before they eventually recover from it.
Could this thought Wade account for Clerviius's apparent resurrection, regardless
of what exactly had happened. That Clerviius could ever have
been declared dead in the first place raises a deeply
un settling question. Just how exactly do we determine whether
(02:04):
somebody has well and truly died. It may be surprising
to discover that it isn't by any stretch an exact science.
In years gone by, the death of a human individual
was believed to have occurred simply when breathing had stopped
(02:26):
or the heart was no longer beating. More recently, we
have come to understand that absolute death comes only when
the brain has irreversibly ceased to function. However, it wasn't
until nineteen sixty eight that a definition of brain death
previously referred to as irreversible coma, was first formalized according
(02:50):
to the Harvard Medical School Committee that to find it.
The process for confirming brain death is fourfold. First, the
body's responsiveness is taken into consideration, whether even the most
painful stimuli failed to elicit a reaction. Next, the body
is monitored for signs of spontaneous movement and breathing. Does
(03:12):
it require a ventilator to remain alive, for example. Thirdly,
the body's reflexes will be assessed, most commonly by examining
whether pupils respond to light or whether they are fixed
and dilated. Finally, having taken all of that into account,
an electroencephalogram or EEG should be used to test for
(03:35):
any sign of brain activity. Only after all the correct
criteria have been met could an individual be determined to
have well and truly died. Although this definition has been
refined somewhat since nineteen sixty eight, with today's modern fMRI
scanners a far more sophisticated way to measure brain activity,
(03:56):
the basic process for determining the death of an individual
remains more or less the same. And yet, just as
we used to think that a stopped heart or final
breath was evidence of death. Might it also be the
case that the criteria for supposed brain death could also
one day prove to be an inadequate measure of a
(04:18):
complete demise. Perhaps, just like in the days before we
were able to measure brain activity, there might yet be
some future more sophisticated technology to reveal the horrifying truth
that brain death is in fact not a permanent, irreversible state.
Could what appears to be a dead brain in fact
(04:40):
still remain one with the potential to regain consciousness? Are
you always taking care of your family? Do you often
take care of others and not yourself? Now it's time
to take care of yourself, to make time for you
you deserve it. Tell a DOC gives you access to
a licensed therapist to help you get back to feeling
(05:02):
your best, to feeling like yourself again. With TELEDOC, you
can speak to a licensed therapist by phone or video.
Therapy appointments are available seven days a week from seven
am to nine pm local time. If you feel overwhelmed
sometimes maybe you feel stressed or anxious, depressed or lonely,
or you might be struggling with a personal or family
(05:25):
issue teledoc can help. Teledoc is committed to facilitating great
therapeutic matches, so they make it easy to change counselors
if needed. For free teledoc therapy is available through most
insurance or employers. Download the app or visit teledoc dot
com forward slash Unexplained podcast today to get started. That's
(05:47):
teladoc dot com slash Unexplained podcast. In early twenty nineteen,
a team of neuroscientists from Yale School of Medicine, led
by its Vonomere vi Celia and Stefano Danielli, published a
remarkable paper in Nature which, although not providing proof by
(06:09):
any stretch that an individual might recover consciousness from a
supposed brain death, has nonetheless reignited the debate over just
what is or isn't irreversible. It is well understood that
reducing oxygen and blood flow to the brain can have
rapid and devastating consequences. Just a few seconds without oxygen
(06:30):
will result in a loss of consciousness. After five minutes
a dino scene, triphosphate or atyp the body's primary source
of cellular energy, will run out. If perfusion, the flow
of blood and oxygen is not restored, a progressive and
largely irreversible spiral of mechanical failure ensues from the build
(06:53):
up of carbon dioxide to the emergence of enzymes that
begin to break down the nerve tissue, which will lead
inevitably to the death of the brain. Although in the past,
individual cells taken from brains long after death have been
shown to continue to function, performing processes such as making proteins.
(07:14):
What Vesselia and Danielli's team wanted to know was could
a whole brain be revived a number of hours after death.
To test this out, researchers collected thirty two severed heads
of pigs that had been slaughtered in an abatoir close
to the team's laboratory. The brains, having been removed from
(07:36):
the skulls, were then placed in a chamber and fitted
with catheters. After waiting four hours from the moment of decapitation,
each brain was given an EEG to confirm a flat
line of brain activity before a warm substance containing nutrients
and oxygen was slowly pumped into them. The system, known
(07:57):
as brain X, developed especially for the experiment, is essentially
a brain specific dialysis machine designed to mimic the original
host's blood flow. Although they didn't expect the brains to
regain consciousness, the team used a chemical agent in the
solution to reduce the possibility of this happening. With the
(08:17):
solution cycling through the brains, all the scientists had to
do next was stand back and wait. After six hours
of tests, the results were startling. As an experiment to
test the efficacy of the brain X system, things could
not have gone better, as almost complete circulation was restored
(08:39):
to the brains. Blood vessels remained in such good shape
throughout the experiment that they continued to function in the
manner of a living brain. The system also succeeded in
preserving the global structure of the brain. Tissue areas that
are particularly susceptible to a lack of oxygen include the hippocampus,
(09:01):
which plays a vital role in the consolidation of memories,
were also well preserved. Comparing the solution as it flowed
to and from the brains. Research has also discovered signs
of metabolic activity as individual cells began to function again,
generating carbon dioxide while absorbing glucose and oxygen. But most
(09:24):
striking of all, when small slices of tissue were tested
after treatment, the team discovered that at least some neurons
remained capable of neural activity, a process thought fundamental for
generating consciousness. As the team from Yale were keen to stress,
(09:48):
their findings did not signify a resurgence of normal brain function. However,
as others, including science journalist Sarah Reardon and the brain
X team themselves have pointed out, since significant measures were
taken to prevent this from happening, there is no knowing
as yet what might have occurred under different circumstances, and
(10:10):
even if the brain EX system was not enough to
resurrect a consciousness from a dead brain, it would not
be the end of the road for such a pursuit.
It may be the case that some additional, as yet
unknown action might be needed to kick start this into life.
After all, only in nineteen forty seven, thanks to the
(10:30):
Maverick instincts of cardiac surgeon Claude Beck, was it confirmed
that an electrical shock could restart a human heart. Certainly,
it remains to be seen if an individual's sense of
consciousness could be restored after their brain has been declared
clinically dead by today's standards. However, if history is anything
(10:51):
to go by, that we haven't discovered yet how this
might be achieved is no indication that it cannot be done,
And with this comes some unsettling ideas just how much
of a brain is required, or more specifically, how many
of its constituent parts are necessary for a sense of
(11:12):
consciousness and self awareness to emerge, even if we think
not enough sections have been reactivated for this to occur.
Might the brain be able to construct modes of conscious
self awareness that we are not yet aware of and
therefore wouldn't even know if they had been activated or not.
And if, by some miracle it were possible to restore
(11:35):
a sense of self awareness in a previously dead brain,
whose self awareness would it be the individual that existed
before death or something else, perhaps before we dismiss entirely
the more alarming possibilities, As pointed out by the authors
of a recent Comet piece about the remarkable brain X experiment,
(11:57):
we might do well to ponder the wise word sub
miracle Max from the nineteen eighty seven film The Princess Bride.
There's a big difference between mostly dead and all dead.
Mostly dead is also slightly alive. If you enjoy listening
(12:20):
to Unexplained and would like to help support us, you
can now go to Unexplained podcast dot com, Forward slash Support.
All donations, no matter how large or small, are massively appreciated.
All elements of Unexplained are produced by me, Richard McClain smith.
Please subscribe and rate the show on iTunes, and feel
(12:42):
free to get in touch with any thoughts or ideas
regarding the stories you've heard on the show. Perhaps you
have an explanation of your own you'd like to share.
You can reach us online at Unexplained podcast dot com,
or Twitter at Unexplained Pod and Facebook at Facebook dot com.
Forward Slash Unexplained Now, it's time to take care of yourself.
(13:10):
To make time for you, teledoc gives you access to
a licensed therapist to help you get back to feeling
your best. Speak to a licensed therapist by phone or
video anytime between seven am to nine pm local time,
seven days a week. Teledoc Therapy is available through most
insurance or employers. Download the app or visit teledoc dot com,
(13:34):
Forward Slash Unexplained Podcast Today to get started. That's t
e ladoc dot com, slash Unexplained podcast
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