National Geographic

In Dying Brains, Signs of Heightened Consciousness

We often talk about death as a point in time. One moment you’re alive and the next, when your heart stops beating and your lungs stop breathing, you are clinically dead. This definition tempts us to view death as a clear-cut event, like the flip of a switch.

That’s not how Jimo Borjigin, a neuroscientist at the University of Michigan, sees it. “Doctors assume that after clinical death, the brain is dead and inactive,” she says. “They use the term ‘unconscious’ again and again. But death is a process. It’s not a black-or-white line.”

In a new study, Borjigin discovered that rats show an unexpected pattern of brain activity immediately after cardiac arrest. With neither breath nor heartbeats, these rodents were clinically dead but for at least 30 seconds, their brains showed several signals of conscious thought, and strong signals to boot. This suggests that our final journey into permanent unconsciousness may actually involve a brief state of heightened consciousness.

Although the experiments were done in rats, Borjigin thinks they have implications for the near-death experiences (NDEs) reported by one in five people who are resuscitated after their hearts stop. Although they were unconscious, unresponsive and clinically dead at the time, they come back with stories of bright lights, “realer than real” memories, and meetings with people they knew. Some scientists have dismissed these accounts outright. Others have taken NDEs as proof of a religious afterlife or a consciousness that lives on outside the body, as popularised in a recent bestseller of dubious provenance.

But Borjigin’s research suggests that these experiences could just be a natural product of a dying brain. That doesn’t make them any less real, but it does root them in the natural world, without the need for a “super-“ prefix.

“The near-death experience might be considered a “final frontier” of consciousness studies,” says George Mashour, an anaesthesiologist from the University of Michigan and a co-author on the study. “It has been repeatedly proposed as a critical counter-example undermining the hypothesis that consciousness is rooted in the brain.  Our study brings the phenomenon back into the realm of brain science.”

What they found

The seeds of this study began in 2007, when Borjigin, together with her husband Michael Wang, was studying the brain activity of rats that had just suffered a stroke. During the experiment, three of the animals unexpectedly died overnight. When the duo found them the next day, they noticed several dramatic peaks of strong brain activity just after at the point of death. “That stuck in my mind,” says Borjigin. “I became convinced that if something is going on in the brain after cardiac arrest, it’s got to be measurable.”

Her team implanted several electrodes across the brains of nine rats to measure their brain waves—rhythmic pulses of neural activity that are denoted by Greek letters, depending on their frequency. The rats were sedated with anaesthetic, and then killed with either a lethal injection that stopped their hearts, or a fatal dose of carbon dioxide.

As you’d expect, after their hearts stopped, most of these brainwaves weakened with time. But one set—the low-gamma waves produced when neurons fire between 25-55 times per second—became stronger for a brief period, in all of the nine rodents. “We weren’t surprised that we found brain activity but we were surprised by the high degree of it,” says Borjigin.

The activity in different parts of their brains also became more synchronised. Their low-gamma waves, in particular, became twice as synchronised when they were in their near-death state than when they were anaesthetised or awake.

These features have been linked to conscious perception in earlier studies. For example, low-gamma waves suddenly become synchronised across distant brain regions at the moment when people recognise a face among some arbitrary shapes. This makes sense—the act of recognition draws upon the brain’s visual centres, as well as areas responsible for face recognition and memory. Neurons all over the brain need to mount a global response, and fire together.

Conscious thought has also been linked to the strength of connections between the front-most areas, associated with many complex mental abilities, and those nearer the back that deal with sensory information. And sure enough, the team saw that these areas became 5-8 times more strongly connected after cardiac arrest than during either anaesthesia or their waking moments. “That’s astonishing,” says Borjigin. “It helps to explain why [humans experiencing NDEs] can ‘see’ during clinical death, and why they claim they can hear conversations during that period.”

What it means

“Near-death experiences are a physiological reality, but science and medicine haven’t taken them seriously for way too long,” says Steven Laureys, who leads the Coma Science Group at the University of Liège. “We can’t just listen to extraordinary stories from patients; we need to measure brain function. The field needs studies like these.”

Laureys compares the study of NDEs to our growing understanding of dreams. For the longest time, we only knew about dreams from the colourful stories people told when they woke up, but electrode measurements revealed their neurological underpinnings, including the existence of REM sleep when most dreams occur. “That’s the way we should go for death and NDEs.”

However, he also cautions that scientists are still arguing about which neural signals are indicators of consciousness, so decoding the patterns that Borjigin saw isn’t straightforward. “It’s terribly hard to make strong claims about what these rats actually perceived, or about possible conscious experiences,” he says. “But the study definitely shows that there is a lot more electrical activity than expected, and it’s very interesting activity. It’s tempting to link that to what we hear in patients, but we need to be very careful.”

Sam Parnia, a cardiologist from Stony Brook University Hospital, shares that view. He has studied resuscitation and near-death experiences for years and believes that comparing the rat results to the intense visions that humans recount after NDEs “is extremely premature and unsupported by evidence”.

“We have a long way to go,” admits Mashour.  “We haven’t correlated the observed brain activity with a conscious experience.” The only way to get around that would be to gather electrode recordings in someone who had a near-death experience and returned to tell the tale. There are only a few possible situations when that wouldn’t be unethical—perhaps with organ donors who are undergoing cardiac death.

Meanwhile, Parnia says that there could be other explanations for the results. “After blood flow to the brain is stopped, there is an influx of calcium inside brain cells that eventually leads to cell damage and death,” he says. “That would lead to measurable electroencephalography (EEG) activity, which could be what is being measured.” This would explain why Borjigin saw the same pattern in every dying rat, while only 20 percent of people experience NDEs after a heart attack.

Parnia also notes that other EEG studies of humans during cardiac arrest haven’t found similar patterns, suggesting that these results might be due to some quirk of the experiment. But Borjigin counters that other groups have mostly placed electrodes on their patients’ scalps, with bone, flesh and skin standing between them and the underlying neurons. Her team, however, surgically implanted their electrodes right on top of the rats’ brains, making them more sensitive to subtle signals.

To her, the signals are a sign of heightened consciousness and she speculates that such spikes of activity might be a sort of built-in defence. “When the brain is in danger, it needs to be hyper-alert, so the individual can deal with a crisis,” she says.

This raises some other intriguing questions, beyond the relevance to NDEs. “We didn’t realise that brains can have heightened consciousness when oxygen and glucose are taken away,” she says. “Could this happen during our waking states, or when we’re ill, praying or meditating? If you have local fluctuations, could that give you hallucinations or artistic visions? We don’t know.”

Reference: Borjigin, Lee, Liu, Pal, Huff, Klarr, Sloboda, Hernandez, Wang & Mashour. 2013. Surge of neurophysiological coherence and connectivity in the dying brain. PNAS http://dx.doi.org/10.1073/pnas.1308285110

There are 31 Comments. Add Yours.

  1. Ethan Siegel
    August 12, 2013

    Finally, neuroscience catches up to what we all knew from watching “Flatliners” as kids!

    Really cool research, Ed, thanks for sharing.

  2. Rdizzie
    August 12, 2013

    Amazing article. This however reminds me of the movie “Donovan’s Brain” mixed with the movie “Re-Animator” and a touch of “Flat Liners” all good films btw. I saw somewhere that recently they have found the chemical that causes the body to die (I may have worded this wrong), coupled with this discovery maybe a mix of these three movies can soon become reality. I can’t recall this “death hormone” and the specifics of it but it was something like; during the death process a chemical in our body is released that when combined with oxygen it causes our cells to die. Unless I am remembering this incorrectly.

    Now I am no doctor nor any kind of expert, but my personal thoughts on this topic are as follows. Life what ever gives that “spark” as it is often called is in a way energy, and it is a known fact that electrical functions facilitate life at least in higher life forms as far as I know. We also know that energy can not be lost only reformed, so if that “spark” is energy of some kind then perhaps the thought of afterlife is not so far fetched. Now I am not claiming this to be fact, it just makes sense to me that it is possible. This also brings up the question of the ghost. Now I heard Hawking say that like all other matter time is not perfectly smooth and has holes in it, though very tiny, sometimes called “worm holes” Perhaps what we call ghosts is nothing more than energy that has gotten caught in one of these holes and is allowed to leak into our time briefly. Though at the risk of getting off track and sounding more of an idiot I will stop there.

  3. Max_B
    August 12, 2013

    Hold on though Ed… effectively, the researchers made some rat brains exhibit highly synchronised activity, which was extremely similar to activity seen in ‘wakeful’ humans when they ‘perceive visual stimuli’ and when they undertake visual tasks’. The major point being that the rats were in cardiac arrest at the time!

    Can you just accept that, without being astonished? How do you make the brain of a rat in cardiac arrest, look like the brain of a wakeful human undertaking a visual task???

    Perhaps the researcher got their head too close to the rat? Is it a clue about the veridical OBE portion of the NDE? Does it tell us anything about EM fields generated by the brain? Wild ideas…

    Its a fantastic paper, but it would be really interesting for Borjigin to run the experiment again, but this time totally isolating each individual rat inside a fully electrically and magnetically shielded chamber, and see if she gets the same highly synchronised Alpha-Gamma coupling seen in wakeful humans undertaking visual tasks?

  4. Kevin
    August 13, 2013

    What about DMT flooding the brain from the pineal gland in birth and death? Sounds more plausible now…

  5. Erik Vance
    August 13, 2013

    Well laid-out. Though, to be fair to afterlife believers, if I see my grandma as an angel just after I die my gamma waves would spike, right? I guess, presuming I am a rat that is.

  6. KH
    August 13, 2013

    It’s great that science can start explaining phenomenon surrounding death but this also means that it is eroding the last bit of compassion that Mother Nature has left as a parting gift for the dying person. Now I shudder at the thought that when my heart stops pumping, I’m fully aware of this “self” passing away into oblivions…..

  7. Wut
    August 14, 2013

    What’s a hustle for a hustler if it’s in the wrong direction…

    Some say that in order to solve a question, you have to create a higher level function. Then I would presume we should take our cues from the highest operators of intelligence, or the collective consciousness instead. Yes, of course attitudinal/directional data has its limits but I would imagine it would be better to infer the existence of an intelligible laser coming through a one way mirror by asking the humans in the interrogation room as opposed to studying the mechanics of rats in the corner…

  8. Wut
    August 14, 2013

    PS. But to the scientists’ defense, maybe they really are just trying to study the mechanical operations as opposed to proving anything besides. I may have misunderstood the underlying intent of the study.

  9. Markus A. Dahlem
    August 15, 2013

    Flogging a dying rat.

    The paper seems to completely ignore the literature on so called spreading depolarizations and anoxic depolarizations.

    See for example:
    Dreier, J. P. , The role of spreading depression, spreading depolarization and spreading ischemia in neurological disease, Nat. Med. 17, 439 (2011).

    or for theoretical studies:
    Neural Dynamics during Anoxia and the “Wave of Death”
    Zandt, B. J. , ten Haken, B. , van Dijk, J. G. and van Putten, M. J. , Neural dynamics during anoxia and the “wave of death”, PLoS ONE 6, e22127 (2011).
    doi:10.1371/journal.pone.0022127

  10. Bayesian Bouffant, FCD
    August 15, 2013

    Erik Vance: Though, to be fair to afterlife believers, if I see my grandma as an angel just after I die my gamma waves would spike, right?

    No. If “you” saw something after you died, that would mean that “you” are not your brain, but that “you” are your disembodied consciousness. I.e. you are arguing for naturalistic consequences of a dualistic experience.

  11. Max_B
    August 15, 2013

    “No. If “you” saw something after you died, that would mean that “you” are not your brain, but that “you” are your disembodied consciousness.”

    Indeed, if ‘you’ are not ‘your’ brain, who’s brain might ‘you’ be at that moment?

  12. Max_B
    August 15, 2013

    Borjigin has not considered that the level of shielding used for ‘living’ EEG studies, a Faraday ‘type’ chamber also used in this experiment, might not be adequate for ‘dying’ EEG studies of such sensitivity and resolution.

  13. Chris
    August 16, 2013

    Dr Sam Parnia has been saying for quite some time that death is a process. I’ve been following his experiments for several years now. Unfortunately, it’s impractical to get anything decent like fMRI results or such like from a cardiac arrest patient. Currently, only brain stem activity can be measured on humans suffering a cardiac arrest. It seems plausible that there might still be activity in the brain that cannot be detected through current medical technology in cardiac arrest patients — somewhere other than the brain stem. However, I think it will still be hard to explain how some of these patients can describe things that happened outside the room while they were supposedly dead — in other words out of body experiences. I’ve read some accounts where patients were able to describe things that were happening miles from them while they were being resuscitated. Parnia’s AWARE study is looking into that. Nevertheless, the current consensus seems to be that death is a process and that this may account for NDE’s. Still the philosophical debate about dualism opposed to a strictly materialistic explanation will be unresolved until such time as the out of body experiences of NDE survivors can be adequately explained through science. I have a feeling it has something to do with quantum processes. Sir Roger Penrose touched on this with his quantum mind hypothesis, but Max Tegmark pointed out quite a few problems in that. Still it would explain a lot. Good article.

    • Rdizzie
      August 16, 2013

      @chris. I saw a study done several years back in England where a hospital tested NDE’s with an ad ticker displaying different words and quotes and such through out trama wards in the hospital. I can not recall the exact number of NDE’s patients claimed but I do recall that 0 of them correctly stated the phrases on the tickers. Now if this proves or disproves the OBE is up to debate. I just thought if you didn’t know about that study you would like to.

      • Markus A. Dahlem
        August 16, 2013

        @Rdizzie Thanks for this hint with the study done in England. Do you have a reference?

        Let me also say: there actually is zero need to prove that wrong as there is no need to prove that Uri Geller cannot bend spoons.

        It is a terrible waste of money and recources that should go into other research.

        To be clear, I am not taking about this study and the data. I really like it for various reasons. But to speculate about these spooky phenomena is a waste of time.

  14. dan
    August 16, 2013

    Markus Dahlem is completely right. Furthermore, I have done patch clamp experiments for a while, every time the single cell died (not the animal), it had a surge of activity. Applying this to many cells, and lowpass filtering due to the global effect, could easily result in measured cortical eeg gamma activity

  15. Markus A. Dahlem
    August 16, 2013

    Let me add to this discussion a few points and see whether we agree on this:

    (a) The thermodynamic state of the brain is far from equilibrium. After cardiac arrest or decapitation this state goes into its thermodynamic equilibrium.

    (b) The process into thermodynamic equilibrium takes a rather long time but the important events are probably the ion gradients across the cell membranes that serves as batteries for electric signals needed for information processing.

    If we agree on (a)-(b), the question is how long does it take for the electric signals to disappear irreversibly?

    (c) It takes for this break-down towards flat chemical gradients about 30 seconds. During this break-down for about the first 5 seconds the transmembrane potentials depolarizes to values at which high frequency discharges occur. The time scale of the break-down is mainly determined by the amount of cell membrane surface area per unit tissue volume, in short, the surface area-to-volume ratio.

    (d) The surface area-to-volume ratio is different in different cortical layers and also varies among cortical regions. Layers with large cell bodies have lower surface area-to-volume ratio then the neuropil, for example. Moreover, there is a considerable heterogeneity of pial arteries.

    (e) Given the points (c)-(d) there will be a self-organised spatio-temporal pattern of electric discharges on the way to equilibrium in the cortex. Of course, similar events occur in subcortical structures.

    The next question is: Is this process irreversible?

    Again, this is well known, but let me put a letter in front of it.

    (f) It takes about another five to eight minutes for the cell to be not only functionally quite (which takes about 30s) but also to become irreversibly structurally dead. This irreversible process occurs already if the cerebral blood flow (CBF) is below ~20% and not only at 0%CBF (corresponding to cardiac arrest or decapitation), but it does not occur, if CBF is still between 20%-80%, while then the cells still are functionally quite.

    (g) At this point (5-8min, global CBF < 20%), you neurons are dead as well as you are, and not one minute earlier, although you might argue that decapitation is rather irreversible, too, and for that reason the death of the decapitated person is matter-of-factly determined immediately.

    All this is the neural correlate of near-death experiences. Also in transient ischemic attacks or migraine with aura people sufferer from out-of-body experience. I conclude point (e) corrsponds to some form of hallicinations, as would be well expected.

    I cannot see any need to speculate about dualistic experience, though.

  16. Max_B
    August 16, 2013

    Interesting speculations Markus…

    Considering your comments, I’d be interested how you fit these sorts of observations into your ideas:

    Albrecht-Buehler’s research over many years showing inexplicable cell behavior that strongly indicates sensory and processing capability of cells, and apparently cell to cell communication in the ‘near-infrared’ portion of the electromagnetic spectrum… an example paper…

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC49903/

    Frohlich & McCormick’s (2010) stunning paper which demonstrates that neocortical neuronal networks may not only be defined by their anatomical interconnectivity and the status of the synaptic activity that binds them together, but also by the spatially and temporally complex Electro Magnetic Fields in which they are embedded…

    http://www.cell.com/neuron/abstract/S0896-6273%2810%2900463-0

    Other important studies showing the modulation of local field potentials in the V1 and V2 visual areas of the brain correlate with perception. As well as the difficulty in explaining our normal visual experience of reality, without the use of ‘binding fields’.

    Then consider that…

    In Borjigin’s study, the rats were isolated within a Faraday ‘type’ chamber during the experiment, as used for other ‘living’ EEG studies. But Borjigin doesn’t appear to have considered that the level of shielding used for ‘living’ EEG studies, might not be adequate for ‘dying’ EEG studies of such sensitivity and resolution.

    It seem entirely plausible to me that the highly synchronised, and high power gamma / alpha-gamma measurements in the 12-30 second period during cardiac arrest, might have been partly due to the effect of external fields (that were not properly shielded) synchronising the firing of neurons in the rats dysfunctional brain.

    As I understand it, a Faraday type cage blocks electrostatic fields, might be quite good at shielding EM fields (but we don’t know the design used in Borjigin’s study), and is ineffective on slower magnetic fields.

    Considering that the human brain has been shown to respond to weak magnetic fields, and nobody yet knows how it acually does that, it seems reasonable to rule out external field effects from future studies?

  17. Max_B
    August 16, 2013

    @Markus A. Dahlem Interesting speculations…

    Considering your comments and your expertise, I’d be interested how you fit these sorts of observations into your ideas:

    Albrecht-Buehler’s research over many years showing inexplicable cell behavior that strongly indicates sensory and processing capability of cells, and apparently cell to cell communication in the ‘near-infrared’ portion of the electromagnetic spectrum… example paper…

    ‘Rudimentary form of cellular “vision”.’ G Albrecht-Buehler. Proc Natl Acad Sci U S A. 1992 September 1; 89(17): 8288–8292.

    Frohlich & McCormick’s paper which demonstrates that neocortical neuronal networks may not only be defined by their anatomical interconnectivity and the status of the synaptic activity that binds them together, but also by the spatially and temporally complex Electro Magnetic Fields in which they are embedded…

    ‘Endogenous Electric Fields May Guide Neocortical Network Activity’ Flavio Fröhlich, David A. McCormick. Neuron, Volume 67, Issue 1, 129-143, 15 July 2010

    Other important studies showing the modulation of local field potentials in the V1 and V2 visual areas of the brain correlate with perception. As well as the difficulty in explaining our normal visual experience of reality, without the use of ‘binding fields’.

    Then consider that…

    In Borjigin’s study, the rats were isolated within a Faraday ‘type’ chamber during the experiment, as used for other ‘living’ EEG studies. But Borjigin doesn’t appear to have considered that the level of shielding used for ‘living’ EEG studies, might not be adequate for ‘dying’ EEG studies of such sensitivity and resolution.

    It seem entirely plausible to me that the highly synchronised, and high power gamma / alpha-gamma measurements in the 12-30 second period duringcardiac arrest, might have been partly due to the effect of external fields (that were not properly shielded) synchronising the firing of neurons in the rats dysfunctional brain.

    As I understand it, a Faraday type cage blocks electrostatic fields, might be quite good at shielding EM fields (but we don’t know the design used in Borjigin’s study), and is ineffective on slower magnetic fields.

    Considering that the human brain has been shown to respond to weak magnetic fields, and nobody yet knows how it acually does that, it seems reasonable to rule out external field effects from future studies?

    • Markus A. Dahlem
      August 16, 2013

      That cells communicate via what is called ‘volume transmission’ and not exclusively via synaptic transmission is absolute clear—in fact, I work on various of these mechanisms and therefore know for example Flavio’s work and him personally very well.

      Of course these observed oscillations are not explain by single cell behaviour—actually that is what I am saying when I wrote about a “self-organised spatio-temporal pattern of electric discharges”.

      My point is, there is absolutely nothing in this data that gives rise to a dualism of any kind. To discus this, as is done here, is to my mind simply nonsense in this context.

      This data—which is great to have—needs to be discussed in connection with stroke, migraine with aura, and hallucinations (including but by far not limited to (!) out-of-body experiences).

      You may even think about how external electric fields influence the brain activity—again something I work on.

      If you think about migraine therapy, this is really a fascinating question. Whether the brain is more susceptible to neuromodulation by electric or magnetic fields in the state of reduced blood flow, we don’t know. What we know: there is no need for dualism to address this question.

  18. Markus A. Dahlem
    August 16, 2013

    Lets just take the last question to further support my only statement that is should be discussed in a different well known context: “Could this happen during our waking states, or when we’re ill, praying or meditating? If you have local fluctuations, could that give you hallucinations or artistic visions? We don’t know.”

    Answer: Yes it can. There is a whole literature on migraine art. Its roots may be traced back to 19th century neurology.

    Let me quote from the website I run together with Klaus Podoll [1]:

    “Migraine Art denotes the idea that techniques of pictorial representational art may provide an adequate and sometimes the best suited medium to express and communicate those experiences which occur as signs and symptoms of migraine or as reactions of the migraine sufferer to the said manifestations of the disease.”

    [1] Link: http://www.migraine-aura.org/content/e24966/e25413/e25414/index_en.html

  19. Max_B
    August 16, 2013

    @Markus A. Dahlem Thanks, I have to say I’m pretty disinterested in the philosophy of it… I’m reasonably sure I wouldn’t be conscious if I didn’t have a brain :)

    However, whilst considering what we have both said regarding the modulation of neural activity by external fields. I remain intrigued by Borjigin’s results, and her hypothesis that visual cortex seems particularly affected during cardiac arrest.

    In particular, that she is willing to draw attention to neural activity that looks similar to results from recent studies on visual task processing, and the perception of visual stimuli in humans during wakefulness.

    It’s interesting to consider, just how susceptible to external fields the brain might temporarily become during reduced blood flow? Or perhaps more importantly, in the absence of the brains own endogenous fields, or when those same fields become dysfunctional?

    The human visual cortex is a big bugger, if ideas about binding fields, synchrony and perception are correct, and considering fields definitely leave the scull (otherwise we couldn’t pick them up), perhaps it might be possible to entertain some far-out speculation on the rare OBE portion of the NDE during cardiac arrest?

    I mean that in the absence of other sensory data, what might be the temporary effect of external third party fields (binding/visual or otherwise) on the dysfunctional brain of a cardiac arrest patient?

    Henrik Ehrsson’s work [1] (amongst others) appears to show support for the shifting of self-location in space, and the difficulty the brain appears to have in perceiving the ‘self’ to be located at two different places at the same time.

    I’m just speculating on the often ‘floating’ OBE perspective recalled by experiencers in a clinical setting where more than one third party is in close proximity to the patient when the go into cardiac arrest?

    If – big if – the patients brain were temporarily susceptible to external third party binding fields. How might the brain attempt to reconstruct brief flashes of garbled external visual data from third parties, and where might it place ‘self’ in a logical effort to unify the imagery…

    Anyway, I find it intriguing that rats in cardiac arrest exhibit neural activity that looks similar to wakeful human visual processing.

    I find it good fun speculating on this subject…

    [1] Guterstam A. & Ehrsson H.H. Disowning one’s seen real body during an out-of-body illusion. Consciousness and Cognition (28 Feb 2012), DOI: 10.1016/j.concog.2012.01.018.

    • Markus A. Dahlem
      August 16, 2013

      @Max_B: I am happy to close the philosophy chapter.

      Intriguing thoughts! In particular, what happens “in the absence of the brains own endogenous fields, or when those same fields become dysfunctional”? What can we infer from experiments that have been performed in the presence of these functional fields.

      Not much but enough. After about 30-60 seconds, the chemical gradients are flat, the neurons approach their Donnan equilibrium. We called this state it in a recent paper the twilight state close to death [1].

      In this state, the transmembrane potential might or might not be more affected by external electric stimulation. What the transmembrane potential certainly will not do anymore, is to react on this external stimulation with any kind of activity on its own (action potential).

      The question is then, what if only a fraction of the cells are functionally dead (eliminated gradients) but enough are still functioning?

      The only useful remark I can probably make here is that in any case the fields you are taking about are simply by far too low.

      I consider these questions however important for neuromodulation, that is, electric or magnetic fields from medical devices to stimulate the brain.

      Refs

      [1] Dreier, J. P. et al, Is Spreading Depolarization Characterized by an Abrupt, Massive Release of Gibbs Free Energy from the Human Brain Cortex?, Neuroscientist 19, 25 (2013).

  20. Max_B
    August 16, 2013

    @Markus A. Dahlem

    “The only useful remark I can probably make here is that in any case the fields you are taking about are simply by far too low.”

    Thanks… I keep wildly fantasising about feedback loops, and thinking about neurons ‘writing’ into a endogenous homogenous field, which is ‘read’ back by ‘something-else’ far more sensitive, which would also modulate the neuron on the next loop.

    So that momentary loss of the endogenous field, would still allow the ‘something-else’ (far more sensitive and reasonably passive), to continue to temporarily read back any field within which it is embedded.

    Some of the latest papers on artificial MT’s and interesting new theories showing ways of ‘concentrating’ magnetic fields either inside, and on the outside surface of new tubular materials excite my interest.

    A little off the subject, and because you are interested in magnetic effects on the… (and before I finally wrap up this interesting conversation)… Astronauts to Mars… any reasons to suggest there might be unexpected long-term effects on the human brain when it leave earths low-frequency magnetic field, and exchanges it for a different magnetic field?

    First time away from home… n all that?

    • Markus A. Dahlem
      August 16, 2013

      Max_B: Be assured that I share your fascination with feedback loop and the brain.

      When it comes to extreme sensitivity of the brain with regard to closed feedback loops, I for my part thing about functions such as reading involuntary facial microexpressions.

      Why on heavens earth (pun intended, I don’t know anything about the Mars) would the brain in an energy compromised state be more sensitve to input while it rather should be much concered to get its obvious interal problem quickly solved?

  21. Max_B
    August 16, 2013

    @Markus A. Dahlem

    Well in an attempt to answer to your last question.. ‘one’ speculation perhaps… simply that both processes (writing to the field, vs, reading from the field) might consume different amounts of energy, so there could be a small miss-match in timing as to when each process fails when resources run low?

    In this energy compromised state, I can’t see any reason for the ‘read’ function to be anymore sensitive to input than normal? Merely perhaps that instead of reading it’s own strong and synchronised problem-solving endogenous ‘write’ field, it starts picking up external field noise from the next strongest compatible synchronised source, and tries to loop it too… which presumably wouldn’t last long.

    I really don’t know, I just enjoy speculating about these things, whilst considering the strange observations in papers that still have no established mechanism to explain them.

    I mean, cells that move around without neurons are interesting don’t you think? I certainly assume not conscious, but never-the-less, observations that imply some type of processing, sensory and organisational capability. That’s why I brought up Albrecht-Buehler’s research earlier… with an example paper which is worth reading:

    ‘Rudimentary form of cellular “vision”.’ G Albrecht-Buehler. Proc Natl Acad Sci U S A. 1992 September 1; 89(17): 8288–8292.

    Very odd observations… but his published papers in this field have left me interested.

    • Markus A. Dahlem
      August 16, 2013

      Really interesting this rudimentary form of cellular “vision”.

      But I think these are simply ephaptic signaling effects given a new name to make them sound more cool. (I’ve read just the abstract.) Still to indicate that ephaptic signaling is a form of rudimentary vision is worthwhile mentioning.

  22. EnglishAtheist
    August 20, 2013

    This research was used as evidence for the soul’s existence on Thought for the Day
    http://furtherthoughtsfortheday.blogspot.co.uk/2013/08/scientific-evidence-for-soul.html?m=1

  23. Chuck Anziulewicz
    August 20, 2013

    Either this research indicates that intimations of an afterlife are nothing more than electrochemical phenomena in the dying brain … or that Heaven is filled with RATS.

  24. Focault
    December 13, 2013

    “In a new exercise by a California organization that studies lucid dreaming, volunteers have been conditioned to dream near-death experiences, including the classic scenario of flying toward a light at the end of a tunnel. The researchers say their experiment demonstrates that these heavenly visions must be products of the human mind rather than supernatural phenomena.”

    Taken from:
    http://www.livescience.com/19106-death-experiences-lucid-dreams.html

  25. Kath Pearson
    April 2, 2014

    Fascinating reading all this data – please could I ask- have any of you had a cardiac arrest?
    I had one five weeks ago and I think a little more respect for survivors would be appropriate, also perhaps you would consider using your undoubtedly fantastic brains for something a little more constructive .

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