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Deja Vu Theory / Some Direction Needed

  1. Apr 23, 2012 #1
    My first post. And a quick warning. The title "scientist" is like "fireman" to a child for me. If I lived my fantasy life, I would be a researcher of some sort...or perhaps a professional scholar. Ahhh...the life. Alas, I am none of those things and so am grossly uneducated on most of these matters. As such, I will try to convey what I "know" and hope someone with more education can point me in a better direction. So here goes.

    Every time I am involved in a discussion on dejavu (or experience it myself) it's usually the same: a fleeting feeling of "I've seen this before" or "I totally dreamt that."

    After a fun debate with someone who swore it was a tale of the future, I fired up the...ahem...tobacco pipe to reflect, and I think I'm on to something.

    My understanding of the eye is that it doesn't capture motion, rather a bunch of images in a short time and this is in turn perceived as motion by our brain, right? So if that's the case, then no matter how small, there is a period of time between what actually happened, and when our brain tell us it happened...right?

    I also recently saw a Nova special (at least, it was hosted by Neil DeGrasse, maybe not Nova specifically), where he investigated various magic tricks. Turns out our eyes lock on to things in motion, and our brain attempts to determine the destination of said object. Some sort of hunter's mechanism (so we could catch mammoths, I assume).

    So with those two things, I wondered. Is it possible that perhaps throughout our day our eyes and brains are playing this sort of game:

    picture taken -> picture sent to brain -> brain notes and uses picture for reference -> brain tries to tell you what happens next (where the mammoth will be in 2 seconds)

    and every once in a while there's a hiccup? Like maybe

    picture taken -> picture sent to brain -> picture lost in the mail -> brain still tries to interpret what it has, and makes the most out of the missing info.

    Does that make sense? For whatever reason, there are missing pictures but our brain still attempts to make sense of the series of events happening around us; and perhaps it sends a signal of the next actions to us before we "see" them.

    I am quite interested in Deja Vu as I've experienced it myself. I just don't like tacking on any theories that simply have no basis (simple math can explain "dreams of the future", so that's out the window). But there has to be some explanation.

    I did realize last night that in fact, I haven't experienced Deja Vu in a long time, and can remember the moments becoming farther and fewer between as I aged. So perhaps, like most other aspects of our being, this is something that happens as our brains get things straightened out.

    Has any (legitimate) research been done on this? Are my thoughts even close to holding water? How would a scientist even test this sort of thing?

    That's it. If this doesn't get me booted from the forum, prepare for my questions on the book "The Secret Life of Plants;" or as I like to call it, 300+ paper airplanes waiting to be made.
  2. jcsd
  3. Apr 23, 2012 #2


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    Welcome Seo!!. You see to have the right attitude for asking questions and a sense of humor. And it seems you are not here to spam us. Which is always a good thing. :wink:
  4. Apr 23, 2012 #3
    My wife would disagree

    I deal with spam for a living. It causes a true, physical pain to my elbow for some reason...so I hate it.

    Thanks for the welcome.
  5. Apr 23, 2012 #4
    Deja Vu is already understood, and has been for many years, by neurologists, but the word never seems to get out to the general public, and people continue to needlessly speculate on what it's about.

    It is caused by the spontaneous hypersynchronous firing of neurons in the area of the brain associated with memory: the hippocampus/amygdala, and surrounding tissue. This activity has been detected and recorded by depth electrodes implanted into the temporal lobes of epileptics being prepped for brain surgery. That is: the activity is recorded at the same time they are verbally reporting the experience of Deja Vu. (The depth electrodes are in place for a long time; days at least, while they do their best to make sure they know what exact area to excise during surgery.)


    Part of the function of the hippocampus is to "flag" things we are experiencing as familiar or not. During these episodes of hypersynchronous firing whatever we are holding in consciousness is erroneously given an emotional charge of hyper-familiarity. The present situation, which you intellectually realize is new and not something you've lived through before, is super-charged with the feeling of being a memory. Despite the impossibility of it, you are emotionally convinced you have seen this before, been here before, lived through this before.

    The opposite of the Deja Vu is also experienced by some: the Jamais Vu, a weird emotional state where that which we intellectually understand should be familiar feels unaccountably unfamiliar. V.S. Ramachandran has discussed a few cases of this in people who seem to have some disconnect between their amygdala and hippocampus. (See his book Phantoms in the Brain.) The amygdala activates the hippocampus. The disconnect, what ever might cause that disconnect, prevents it from doing so, such that a guy starts to believe his own parents have been replaced by imposters, because they fail to elicit the proper feeling of familiarity in him.

    The Deja Vu, where the feeling of familiarity is supercharged, leads to speculation about reincarnation, living through repeating time loops, short term vs long term memory misfiling gltches, etc. It is none of those. It is hypersynchronous firing of neurons in memory-dedicated parts of the temporal lobe.

    So, this is the well-documented medical explanation. It's a mystery that was solved long ago but that information never seems to get disseminated.
  6. Apr 26, 2012 #5
    I once was in a theme park with a few friends. And I slipped in the wave pool and fell back hitting my head backwards. I was dazed n lay still till my friends lifted me and took me to a nearby restaurant, where I started telling my friend near me that I remember seeing everything I'm seeing and he thought I've gone nuts. I recovered soon thereafter and I guess I experienced dejavu because of the impact to my head. I have had no similar experiences after that.

    I guess head impacts can have short term dejavu effects.
  7. Apr 26, 2012 #6
    Thanks for that post Zoobyshoe, I never read what dejavu is. Just assumed it was "many familiar things, producing a sense of I've been through this before." Which really doesn't make sense, I'd get dejavu all the time at work... lol.

    Anyways glad you posted that!
  8. Apr 26, 2012 #7
    This is the first time I've ever heard of an impact to the head giving someone an immediate deja vu. If it's happened to one, though, it must have happened to more.

    If I get ambitious I might scan and post a picture of an EEG of a guy having a deja vu that is in one study I have. The EEG needle is going crazy during the event, which really explains the emotional power of the experience. He also experiences what I experience: the strong conviction you know what is going to happen next. That always ends up be illusory, but while it is happening you are convinced you know.
  9. Apr 26, 2012 #8

    Ivan Seeking

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    How does one differentiate Deja Vu from vague memories of real experiences? Say for example I walk into a house and have the distinct feeling I've been there before, because in fact I was at a very young age but have forgotten.

    I have certainly had the feeling of vague familiarity evolve into a full blown memory, with a little time, in similar situations. But there is no reason to assume that I would necessarily remember the true source of that feeling.
  10. Apr 26, 2012 #9
    Deja Vu's aren't vague. They're intense and that intensity is what calls your attention to them; there is a sort of too-intense-to-be-true quality to them. If I have a deja vu here in my apartment, you might ask why shouldn't it seem familiar, I am here for hours every day. The question is: why should it's familiarity suddenly jump out at me and become the single most important thing about it to me emotionally, such that it's all I can think about?

    Then there's the impossibility factor. A guy I knew had a deja vu upon arriving at a house in a state where he'd never been. As he stepped out of the taxi he was astonished to discover he "recognized" the whole scene in front of him: every blade of grass, every area of chipped paint on the clapboards, the blossoms on every climbing vine. If it turned out he had, in fact, been here in his remote youth and forgotten it, none of those details would have been the same, only the general layout.

    Vague memories of real experiences can be nagging and somewhat mysterious, but there is a distinctly different property to a deja vu which I have never been able to successfully describe to someone who hasn't had one. Those who have had one know instantly what I'm talking about. Those who haven't are bewildered and suppose I'm getting inexplicable over-exited about the kind of experience you're talking about: an authentic past experience that you haven't fully recalled yet.

    All I can say is, if and when you ever have one, you'll know it.
  11. Apr 27, 2012 #10
    Deja vu can be www.slatervecchio.com/articles/cases/mild-traumatic-brain-injury-an-introduction.htm [Broken]. In fact it is one of the symptoms of Temporal lobe epilepsy which can be caused by health.rush.edu/HealthInformation/Pediatric%20center/10/000044.aspx [Broken].
    Last edited by a moderator: May 5, 2017
  12. Apr 27, 2012 #11
    Notice I said immediate, though. That's what is novel about your anecdote. Your link, indeed, is mostly about the fact that symptoms of TBI usually take a long time to manifest. (This is why, if you go to the doctor for any reason the history questionaire will ask if you've ever injured your head or had a concussion. It's well known the problems can often take years to manifest.)

    A seizure caused by brain damage is also extremely unlikely to occur once and never again. It's conceivable, but it means your scenario would be based on two rarities.

    Also, I refer you to the wiki article you linked to to read about the causes of Temporal Lobe Epilepsy. The main suspect is hippocampal sclerosis resulting from childhood fevers. Head injury is listed among the rare suspects for that particular kind of seizure. That sums to three rarities needed to support your scenario.

    Much more likely, although of course I'm speculating, is that your brain chemistry was a bit out of balance already that day and the exitement of the theme park experience combined with the shock of the fall dropped you just below the seizure threshold. By "the seizure threshold" I'm referring to the fact that everyone's brain depends on the right balance of chemicals (glucose, hormones, etc.) to keep the neurons stable, so they don't start firing outside useful parameters.
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  13. Apr 27, 2012 #12

    Ivan Seeking

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    Hmmmm, I've had experiences I assumed were Deja Vu but not with the intensity you describe. At the same time, the apparent memory was to the best of my knowledge, not possible, which is why I assumed it was Deja Vu.

    Based on this new intensity requirement, which I have never seen mentioned before when dismissing alleged Deja Vu exeriences here in the past, I have to assume that your answer to the OP was incomplete. Only "intense" experiences might be dismissed as Deja Vu, and not just any feeling like this has happened before; been here before, etc. Other similar experiences must be something else?
    Last edited: Apr 27, 2012
  14. Apr 28, 2012 #13
    What, exactly, are you concerned is being "dismissed"?
  15. Apr 28, 2012 #14
    I din't imply that my case was TLE. I just gave you a possible reason for my onset of the so called de javu. I appreciate your reply very much and consider it to be the most likely cause. I would also like to add that the intensity, as quoted by you, of the experience was such that I still remember every minute of it. It was as if I have seen the exact course of events in my dream before. But, as I recovered a couple of hours after the experience, I din't feel compelled to seek medical attention. It's been about 10 years since the incident and I have not had similar experiences.
  16. May 20, 2012 #15
    I think the experience of DejaVu is just a coincidental overlap in the neurons for DIFFERENT memories that somehow combine to give the impression that you are experiencing the SAME thing twice.
  17. Jun 5, 2012 #16
    Similarly, the experience of "love" has been explained by neuroscience, which identifies neurotransmitters and parts of the brain, and so on.

    However, that does not speak to the *grounds* on which we love. Surely these grounds are in some sense present in the psyche, and in some sense exist in the external world.

    The question then is, on what grounds does one experience deja vue? Might there be objective external reasons for *this particular* deja vue?

    One possible analogy might be offered by people who experience "blindsight," a topic you can find on Wikipedia.

  18. Jun 6, 2012 #17
    Can we stimulate these areas of the brain to induce feelings of deja vu or love?

    Do we know what causes these hypersynchronous or hyposynchronous firing of neurons?
  19. Jun 7, 2012 #18
    You'll have to do your own research about love. This thread is about deja vu, and yes, it's been electrically stimulated. I linked to this earlier:


    Hypersynchronous. There's a long list of things that can cause it. Basically the brain requires that certain parameters be met in order for the neurons to fire normally. Anything that upsets those parameters can cause hypersynchronous firing.

    I, personally, have had thousands of deja vu's. As a kid I had scarlet fever and they tell me my temperature got up to 106F. This probably caused some hippocampal sclerosis that predisposes me to hypersynchronous firing in that area of the brain.

    I met a guy who had only had one deja vu in his whole life. His was after a long trip and occurred just as he arrived at his destination. His was probably purely "chemical", the result of lack of sleep, low blood sugar, the stress of travel, that sort of thing.

    There's something called "kindling" that occurs. This means that whenever you experience hypersynchronous firing the neurons seem to become more sensitive. The parameters are narrowed, and it takes less provocation to to start the next occasion of hypersynchronous firing.
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