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Medical Deja Vu?

  1. Sep 25, 2005 #1
    Can somebody explain how and why Deja Vu happens?
  2. jcsd
  3. Sep 25, 2005 #2
    It's a glitch in the matrix. :biggrin:
  4. Sep 25, 2005 #3

    Math Is Hard

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    Try Googling on deja vu and temporal lobe seizures. That might be a good place to start.
    Zoobyshoe is very well-read on this subject and can probably give you a lot of info if he drops by.
  5. Sep 26, 2005 #4
    I have the weird feeling this quetion has been asked before.
  6. Sep 26, 2005 #5
    The deja vu is an incredibly weird sensaton that the present situation you are in is unbelievably familiar, as though you are remembering it from the past even though there's no way it could already have happened.

    Neurologists have proven that it is caused by a tiny bit of seizure activity in the neurons of a part of the brain called the hippocampus. Even though this is technically seizure activity it's nothing to get worried about: all that means is that the neurons are firing all at the same time for no good reason.

    The hippocampus is a major contributor to memory, and performs some vital function in the storage and retrieval of memories. When it gets a power surge like this it creates the false impression that the present is a memory, when it isn't.

    A small seizure like this is called a simple partial seizure. This means it is confined to one small location in the brain, and that there is no loss of consciousness.

    Most people have at least one deja vu in their lifetimes, some have many more than that. The hippocampus is part of the limbic system of the brain, which is the very touchiest part, the most likely to experience seizures.

    What is interesting to me is that there is an opposite to the deja vu called the jamais vu. When a person has this kind of simple partial things around them seem weirdly unfamiliar. They fail to evoke the proper feelings of recognition despite an intellectual realization that you should recognize them. They feel all strange and wrong.

    Here is a site that describes some of the many other weird symptoms that simple partial seizures can cause:

    Simple Partial Seizures
  7. Sep 27, 2005 #6
    If you consistently have dejavu(like many times a day), is that cause for worry?
  8. Sep 28, 2005 #7
    That's hard to say. I went through periods like that and it drove me completely bonkers because I didn't know what they were at the time, and no one could explain them to me. Some a-holes advised me to get right with jesus and they'd probably go away. Other a-holes told me I was being reminded of stuff from a past life. Eventually I ran across mention of them in connection with seizures. More research into this and I finally found studies that had proven they were seizure activity in the limbic system.

    If they are driving you nuts, I would see a neurologist.

    In general neurologists won't bother with people whose only problem is a few deja vu's now and then, because they have so many people with much worse seizures to take care of. Several a day might be enough to cause them concern and give you a scrip for some anticonvulsants.

    They are often associated with migraine as well and there is a large overlap between alot of migraine and seizure symptoms. That is: some people sort of have both migraine and simple partials. Some neurologists jokingly call this "migralepsy". Same meds work for both, usually.

    Do you have any other strange symptoms? Weird visual things, weird body sensations, strong emotions for no reason?
  9. Sep 29, 2005 #8
    You know, I used to have the same attitude about deja-vu as zoobyshoe. Having a scientific-type mind, I couldn't have any other view. However, something happened to me that I can't explain. While sitting in a circle of friends, all of the sudden, my vision was from a bird's eye viewpoint at the corner of the room, looking down on ME and my friends, yet my hearing was still connected in the circle (really different experience). Anyway, I started remembering everything that they were ABOUT to say, and it happened just as I knew, from hearing it before (?) Well, the conversation among my friends continued for ~45 seconds and I didn't intervene because I would have stopped the cycle, if that makes sense. After they got done with the conversation, they all looked at me because I had this weird look on my face apparently. There was no way I could even describe the magnitude of feeling that I had. So, my question is, do you think that there is a possibility that there could be a realm to tap into perhaps from before or something. I KNOW that seizures cause a false recognition in the hippocampus creating false assumptions that the experience has happened, but individuals with seizures do not have any recollection of what occurred. Any ideas to help with this paradox would be helpful. :uhh:
  10. Sep 29, 2005 #9
    You missed the point about simple-partial seizures: there is no loss of consciousness during a simple partial, and the person has total recall of what he experienced. Go to the link I posted above. There are a few quotes from people describing what they go through during their simple partials.

    When a person has no recall for a seizure it is either a complex-partial or a generalized seizure. This difference in terms, simple, or complex, refers to the level of consciousness and recall.

    The experience you had in the group sounds like a simple partial involving temporal, parietal, and occipital lobes of the right hemisphere. I have had the same experience of seeing myself from the outside, which is a simple partial symptom called 'autoscopy' but not in conjunction with a deja vu.

    Seizures are somewhat like fingerprints: no two people seem to have exactly the same mixture of symptoms. For some people the deja vu is accompanied by intense fear. For others it is part of a "dreamy state" where they feel they are in two separate worlds at once. Others start to see vivid scenes from their past appear in the space in front of them superimposed on the the present. The exact experience depends on whether the seizure activity spreads, and, if it does, where in the brain it spreads to. As long as it remains confined to one hemisphere, and doesn't cross over into the other, and stays away from the thalamus, the person will not experience a defect of consciousness and will not have amnesia for the event.
  11. Sep 29, 2005 #10


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    This is just pure speculation on my part, but one possible explanation is that your conscious experience of the conversation was lagging behind the actual conversation for some reason. So you had the information coming into you about who just said what, and this registered on some subconscious level, but your actual conscious experience occurred slightly later. I'm not aware of any other cases of temporal distortion of consciousness like that though. A simpler and less exotic explanation would be that you didn't really know exactly what was about to be said, you just had a strong feeling that you did.
  12. Sep 30, 2005 #11
    When I have alot of deja vus in clusters I inevitably start feeling like I "know" exactly what is coming next. This had to happen to me many times before I realized that what was actually happening is that the feeling of familiarity was becoming attached to the normal train of speculation we all engage in about what is going to happen next, or what someone will say next.

    When what happens doesn't conform to your expectation, it is still imbued with such a strong feeling of failiarity, that you dismiss the fact that the precise thing you were expecting didn't happen, and take the consequent feeling of familiarity as "proof" you did know, but had just gotten the details a little wrong.
  13. Sep 30, 2005 #12
    Ah, good point about the recollection of simple/partial seizures, I was unaware of that. If this phenomenon called autoscopy is caused by the seizure, why was I able to "know" what was said before my friends said it. I can't explain it, but it wasn't like my sense of hearing was lagging and my visial perception was intact, because the words that were spoken matched up with their body actions i.e. laughing, pointing etc. It just seems that in today's world, there are more people trying to debunk this idea because it just can't be proven yet. I say yet for the reason because everything was undiscovered at one time or another, for instance, gravity. So why can't there be this phenomenon of acheiving a different "cause & effect" wavelength? Any thoughts?
  14. Sep 30, 2005 #13


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    Were you doing any drugs or drinking at the time?
    Last edited: Sep 30, 2005
  15. Sep 30, 2005 #14

    Deja-vu feels more like you are slightly ahead in time of everybody else and then when it's over, you slip back to your own time frame and relive the moment.

    My only wish is that I would go a little further into the future to get the lottery numbers, heh.

    However, no deva-vu is the same, sometime you just become familiar with the surroundings and thats it. Other times, I have experienced my soul, or conciusness actually try to depart from my body for a few seconds. I can't really explain it, but it's like everything ceases to move, and you start feeling weightless. Weird.

    I'm wondering if there is any way to induce deja-vu.
  16. Sep 30, 2005 #15
    In reference to if I was doing any drugs at the time, I had smoked some pot ~3 hours before all this started (pretty much sober). It's not like my reality was so distorted that I couldn't perceive what was taking place. But yes, like I said, hours after I smoked, this took place. Also, at the time (years ago) I was an everyday smoker, so my tolerance had increased quite a bit than the every now-and-then smoker. I'm big into Neuroscience and the understanding of how the brain functions, but I just can't dismiss this experience. I have had other occasions where the surroundings were (familiar) and I almost thought it was deja-vu, but the more I thought about it, I was able to distinguish between the two. However, this other experience was nothing I had ever felt before, and this idea of autoscopy posted by zoobyshoe sounds interesting.
  17. Oct 1, 2005 #16
    The other possibility was that you were experiencing a form of palinopsia:

    "In addition, visual events may curiously perseverate (palinopsia) and remain longer than they should or, even more bizarrely, be repeated after a short interval, for example, the sight of someone walking past the bed may be `replayed' over again after a brief interval, and even repeated a number of times."

    -Introduction to Neuropsychology
    J. Graham Beaumont
    1983, The Guilford Press, p.118

    In other words, you would be having a deja vu + autoscopy + palinopsia as part of the same simple partial. As I said before, the exact experience depends on whether the seizure activity spreads, and if so, where it spreads to. There are probably dozens of reasonable combinations possible considering what all is connected to the limbic system. I think most people just have the feeling of hyperfamiliarity by itself.
  18. Oct 1, 2005 #17
    Wow, that sounds like an interesting topic. Were they ever able to distinguish a mechanism of action for this palinopsia. Sounds more like occipital activity, but you're right about the ability of the seizure to spread, so I'm not sure. Definitely a possibility though. How are you so familiar with all of this?
  19. Oct 1, 2005 #18
    That mention is simply made in conjunction with occipital lesions. In other words they're simply correlating lesions at a certain location with specific sorts of symptoms. They don't always have a good idea of the exact mechanism: why that lesion leads to that particular distortion. "Palinopsia" seems to be applied to any experience where there is some form of visual repetition, and I've read of several different things that fall under this heading. I'm really only offering it as an informed suggestion about your experience.
    Yes, your experience sounds to me like it involved the temporal, parietal, and occipital lobes all at once. I would say this must have been the right hemisphere, because if it had been the left hemisphere you would probably have suffered a language deficit of some kind.
    I was very struck and impressed with Oliver Sacks' book The Man Who Mistook His Wife For A Hat. This lead to reading many of his other books, then similar books by Harold Klawans (another neurologist), then I happened on a book about synesthesia by Richard Cytowic, which mentioned that the deja vu was a common simple partial. Since I had had so many of these crazy-making deja vus, this info lead to a study of seizures in general, and especially the interesting book Seized by Eve LaPlante. I used to go to the medical library of the local university quite a bit and look articles up in the back issues of neurology journals and since I got on the web I've been able to read first hand reports of all kinds of seizures by people posting on epilepsy websites.
  20. Oct 2, 2005 #19
    I seem to be missing the 'how' of this. I don't understand how one could have precise situational deja vu based caused by a seizure in the brain.

    For example, I experience extremely specific deja vu multiple times every day. It is not that I feel a sense of vague familiarity but rather that I can predict the exact happenings down to the second for the next 10 minutes because I had a dream about it a few nights ago or something similar. I have never had this vague feeling that you describe but precise knowledge of how the next several full minutes will occur down to kicking a rock as I walk down the sidewalk.

    How could a seizure in my brain cause this exact fortelling of a period of several minutes?
  21. Oct 2, 2005 #20
    If what you say is true, then you're not having deja vu's, you're having some sort of authentic precognitive experience.

    The experience I'm talking about here is purely illusory: the present seems inordinately familiar despite the fact you know it can't be. Normally this is a shortlived, anomalous feeling, that soon dissipates. When clusters of these happen one after another you can start getting the feeling you know what is going to happen next. In fact, what you think is going to happen next never does except as much as you would expect by chance. If the deja vus continue, however, whatever does happen feels so hyperfamiliar that you tell yourself that it proves you did indeed know what was about to happen, you'd just gotten the details wrong.

    Now, as I said, if you aren't wrong about what is going to happen next, then you are having some other experience, apparently the result of precognitive dreams from your description, and not a deja vu.
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