Everyone must of had that feeling of Deja Vu before?

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In summary, people often think they know things they don't, and the idea of deja vu is just a result of familiarity.
  • #36
We don't normally think of familiarity as an emotion, but if you examine the whole issue in context it's clear that it is, and that a deja vu is the erroneous triggering of an emotional reaction.

Notice that the deja vu has it's opposite, the jamais vu. This is a simple partial during which the sense of familiarity shuts off altogether. The result is that things and situations the person intellectually knows to be familiar feel completely foreign, alien, and strange. The person is confronted by something that looks exactly as they remember it, but fails to elicit any feeling that it's familiar. It seems "wrong" somehow, not the same, as if it's essence had been removed. The same goes for people and places, not just objects, a person might encounter during a jamais vu. They seem like souless copies of the originals.

Familiarity therefore, has to be understood, not as a quality inherent in what we percieve, but as an internally generated reaction to what we percieve. Normally the brain generates a realistic level of this feeling, probably by comparing the current situation to memory. We perceve something, and in a split second the brain has determined the level of our familiarity with it and generated a physiological reation, a "feeling" appropriate to that level. If it fails to do so, as when the hippocampal/amygdala activity is inhibited during a jamais vu things that should feel perfectly familiar won't. If the opposite happens, if the hippocampal/amydala activity is sent into a paroxysmal overreaction the thing will seem falsly superfamiliar.

Repeated exposure to something doesn't produce a feeling of superfamiliarity. In fact, the more we're exposed to something the less we tend to notice it. I'm very familiar with the sight of the laptop in front of me, for example. I see it several hours a day. All this exposure to it doesn't accumulate into a feeling of superfamiliarity, though. I never look at it and become amazed at how familiar it seems.

All emotions are generated in the limbic system of the brain. Normally they are more or less appropriate to the situation and serve some purpose. Fear makes us run from a burning building, amusement relieves stress, etc. But because of the way the brain works any of these emotions can be inappropriately triggered, or, fail to arise when they should.

Deja vu's aren't authentic recognition of things we are familiar with. They are the erroneously amplified activity of a part of the brain that governs the feeling of familiarity, which then becomes falsly associated with our surroundings. (Remember: we think the familiarity is a quality of what we're looking at instead of realizing it's actually a reaction we have to it.) You can't reproduce this experience by repeated exposure to the surroundings because they never actually have anything to do with it in the first place. On the other hand, if you were to electrically stimulate someone's hippocampus where feelings of familiarity are generated you could make anything and everything seem superfamiliar to them.
 
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  • #37
  • #38
Is a sign of frequent deja vu indicative of any possible neurological damage or problems? Is it "normal" to have it? How often is "normal"?

I get Deja-vu probably once or twice a month. The most frequent style I get is walking into a room in which I have never been and saying to myself "Ive been here before..." and then going "Yea, i knew she was going to say that, and I knew that waitress was going to drop that" though I obviously didnt think about it prior. Its about 5 seconds of complete familiarity.
One thing I've noticed is that my brain instantly recognizes it for what it is. The voice in my head says "this seems really familiar, as if it has happened before, BUT IT HASNT"
It doesn't feel as if its an actual memory that you SHOULD have recollected, but rather some dreamt-up creative storyline that you know never existed, but followed the same plot. As if you were remembering a dream as it happened before you. Or that life was following the same lines as a book you had read 10 years ago. You get the feeling of "oh yea i remember that part"
Once again though, the logical part of my mind tells me instantly that the feelings I have of familiarity are not founded and that I haven't been there/seen that before.
 
  • #39
Pythagorean said:
interesting. I didn't think it had been pinpointed that well.
There seems to be some inexplicable gap between neurologists and everyone else. Neurologists have known the deja vu is a simple partial for decades. I think they keep this to themselves because the word seizure is so alarming to most people. The result, though, is that there always seems to be a research team somewhere barking up the wrong tree trying to figure out what deja vu's are from scratch.

The article linked to by Math Is Hard reminds me of an old joke: A guy sees a woman searching the ground in a parking lot at night. "Did you lose something?" he asks? "Yes" she says, I lost a hundred dollar bill." He walks over to where she's searching and offers to help. "Oh", she says, "I'm pretty sure I didn't lose it here. I think I must have dropped it over there." and she points to a spot a hundred yards away. "I'm only looking here because the light's so much better."

Even though the guy in MIH's link knows about simple partials he still keeps searching for a different explanation of deja vu's in all the wrong places because, I think, he wants an explanation he likes better.
 
  • #40
Healey01 said:
Is a sign of frequent deja vu indicative of any possible neurological damage or problems? Is it "normal" to have it? How often is "normal"?

I get Deja-vu probably once or twice a month. The most frequent style I get is walking into a room in which I have never been and saying to myself "Ive been here before..." and then going "Yea, i knew she was going to say that, and I knew that waitress was going to drop that" though I obviously didnt think about it prior. Its about 5 seconds of complete familiarity.
One thing I've noticed is that my brain instantly recognizes it for what it is. The voice in my head says "this seems really familiar, as if it has happened before, BUT IT HASNT"
It doesn't feel as if its an actual memory that you SHOULD have recollected, but rather some dreamt-up creative storyline that you know never existed, but followed the same plot. As if you were remembering a dream as it happened before you. Or that life was following the same lines as a book you had read 10 years ago. You get the feeling of "oh yea i remember that part"
Once again though, the logical part of my mind tells me instantly that the feelings I have of familiarity are not founded and that I haven't been there/seen that before.

Once or twice a month is pretty much harmless and no neurologists would bother treating anyone for that.

You could probably get rid of them altogether by eating a consistant, balanced diet, sleeping well every night, completely avoiding alcohol, and getting light, moderate excercise everyday.

I met a woman a few months ago who had a few simple partials every day. I advised her to see a neurologist. He confirmed they were simple partials, but, since she had just quit drinking and joined AA, he wasn't going to treat her at all. He wanted to wait and see how much they subsided after she stopped triggering them by drinking so much.

edit: if you are also having any other weird experiences you can't explain, especially anything you might call "missing time" or "amnesia" then it would indicate that you should be concerned. It could mean you're having the much more serious complex partial seizures.
 
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  • #41
zoobyshoe said:
Once or twice a month is pretty much harmless and no neurologists would bother treating anyone for that.

You could probably get rid of them altogether by eating a consistant, balanced diet, sleeping well every night, completely avoiding alcohol, and getting light, moderate excercise everyday.

I met a woman a few months ago who had a few simple partials every day. I advised her to see a neurologist. He confirmed they were simple partials, but, since she had just quit drinking and joined AA, he wasn't going to treat her at all. He wanted to wait and see how much they subsided after she stopped triggering them by drinking so much.

edit: if you are also having any other weird experiences you can't explain, especially anything you might call "missing time" or "amnesia" then it would indicate that you should be concerned. It could mean you're having the much more serious complex partial seizures.

No, no missing time. But though I'm still fairly young (23), does anyone else get the distinct feeling that as we get older and older the passing of time speeds up more and more and more? I don't mean immediate local passing of time, but more like weeks, months and years pass faster and faster. I thought at first it was a memory issue where the less immediate things I'm remembering leads to a feeling of less things to recall, therefor a feeling of less time passed than actual. Fortunately though, it still seems my memory is more accurate and deep than 90% of the people around me (both from observation and from them telling me so).

Anyone else get that feeling of time getting shorter and shorter?
 
  • #42
Healey01 said:
No, no missing time. But though I'm still fairly young (23), does anyone else get the distinct feeling that as we get older and older the passing of time speeds up more and more and more? I don't mean immediate local passing of time, but more like weeks, months and years pass faster and faster. I thought at first it was a memory issue where the less immediate things I'm remembering leads to a feeling of less things to recall, therefor a feeling of less time passed than actual. Fortunately though, it still seems my memory is more accurate and deep than 90% of the people around me (both from observation and from them telling me so).

Anyone else get that feeling of time getting shorter and shorter?


Well that's partly true of everyone. Consider that when you were 5 the time between your birthdays was a fifth of your life and now it's one-twenty-ninth, almost six times "shorter" in terms of experienced history. But the other part is that if your mind is active and happily occupied, and your life has a little variety in it, time doesn't flit quite so fast. The space between my birthdays (I am 73) doesn't seem half as long as when I was 36.
 
  • #43
Another attempt at producing a deja vu-like experience -- using hypnosis:
http://news.bbc.co.uk/2/hi/health/5194382.stm
The Leeds team set out to create a sense of deja vu among volunteers in a lab.

They used hypnosis to trigger only the second part of the recognition process - hoping to create a sense of familiarity about something a person had not seen before.

The researchers showed volunteers 24 common words, then hypnotised them and told them that when they were next presented with a word in a red frame, they would feel that the word was familiar, although they would not know when they last saw it.

Green frames would make them think that the word belonged to the original list of 24.

...

After being taken out of hypnosis, the volunteers were presented with a series of words in frames of various colours, including some that were not in the original 24 and which were framed in red or green.

Of the 18 people studied so far, 10 reported a peculiar sensation when they saw new words in red frames and five said it definitely felt like deja vu.
 
  • #44
It is estimated that as many as 97% of people have experienced deja vu.
I have heard this figure before but I now don't trust it since it's not clear to me that everyone who says they've had one is actually having the "authentic" deja vu experience. In my own experience I would estimate that only a third of all the people I've met seemed to have experienced the same thing I have.
Two key processes are thought to occur when someone recognises a familiar object or scene.

First, the brain searches through memory traces to see if the contents of that scene have been observed before.

If they have, a separate part of the brain then identifies the scene or object as being familiar.

In deja vu, this second process may occur by mistake, so that a feeling of familiarity is triggered by a novel object or scene.
This is a misunderstanding of a deja vu. The feeling isn't triggered by the novel object or scene. It happens when it happens, but invariably gets falsly ascribed to the external surroundings. It's rather like the old story of the love potion that makes you fall in love with the first person you meet. The feelings of love come from the potion but are falsly assumed to have been triggered by the first person who show up. What it says later is more like it:
And previous work in France has found that electrically stimulating parts of the temporal lobe can trigger a sensation of familiarity with everything a person encounters.

I find this claim to be problematic:
Of the 18 people studied so far, 10 reported a peculiar sensation when they saw new words in red frames and five said it definitely felt like deja vu.
They were instructed under hypnosis to experience the words as familiar and so it isn't of any particular interest that they reported that they did. It doesn't mean they experienced any authentic deja vu feeling, just that they were faithfully presenting the behavior of someone who had. This is how hypnosis works: the hypnotist elicits a loyalty from the subject to stick with the suggestion. You may recall Feynman's story of being hypnotized, and how he felt an inexplicable obligation to behave in accordance with the post hypnotic suggestion. He didn't authentically feel unable to return to his seat by a certain route. Instead, what he felt was a strong, urgent need to act as if he felt unable to do it, a kind of loyalty to the hypnotist to play the game.

I doubt if anything like a real deja vu was created here.
 
  • #45
Zoob, maybe the Deja Vu you describe as having experienced isn't the classical Deja Vu, but something of a bigger scale, or something different altogether.
I've always thought of Deja Vu as a common, low intensity experience.
 
  • #46
My thinking is that maybe the Deja Vu phenomenon needs a clearer taxonomy. There could be different causal bases, and there could also be different effects that would influence how each is categorized. I am not by any any means dismissing temporal lobe simple partial seizures as the basis for the majority of them, but maybe they only create one or two types of experience which are causally and qualitatively unique.

Outside of that, there could be other types of reported Deja Vu experience which might be worth exploring. Some may be hypnotically induced, dream memory induced, or chemically induced, (or other) and they could certainly vary in intensity or length of the sensation.
 
  • #47
i have this problem, that a short after a certain expirience i get the feeling that i already had a similar expirience a long long ago, but i always find it a false feeling, since i could not retrieve such memory after long scanning... it happens only after the expirience, so I am pretty much sure i can't predict the future =)...

so if it would happen to a man a milisecond after the expirience, it would really seem as deja vu...

but that's all on assuming that the man is ****ed up as the i.
 
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  • #48
-Job- said:
Zoob, maybe the Deja Vu you describe as having experienced isn't the classical Deja Vu, but something of a bigger scale, or something different altogether.
I've always thought of Deja Vu as a common, low intensity experience.
The deja vu as I experience it is described over and over in neurological studies and, as I mentioned earlier, at least a third of the people I know seem to have had the same experience as me, with the same intensity. I can't even begin to entertain the notion mine aren't classic when I've read and heard mine described in so many sources and by so many people. These milder, iffy-er reports like yours are really the more unusual.
 
  • #49
Math Is Hard said:
My thinking is that maybe the Deja Vu phenomenon needs a clearer taxonomy. There could be different causal bases, and there could also be different effects that would influence how each is categorized. I am not by any any means dismissing temporal lobe simple partial seizures as the basis for the majority of them, but maybe they only create one or two types of experience which are causally and qualitatively unique.
I'd rather that the terminology be more precise. Instead of labeling several essentially different things as different classifications of the same thing it would be much clearer and more accurate to have a separate name for each.
Outside of that, there could be other types of reported Deja Vu experience which might be worth exploring. Some may be hypnotically induced, dream memory induced, or chemically induced, (or other) and they could certainly vary in intensity or length of the sensation.
If there are milder experiences of the kind of hippocampal centered seizures that I have then they are simply milder seizures, milder deja vus. I can't, and didn't, say these don't exist. I don't know if they do. No one could say for sure. The reason being that someone like you who may have had one of these, would never be tested with depth electrodes to see if the feeling corresponds to seizure activity. Such an invasive proceedure would never be allowed just for curiosity's sake.

The people whose deja vus have been recorded by EEG were being prepped for brain surgery because of much more serious seizures that weren't responding to medication. The depth implanted electrodes were for the purpose of locating the seizure focus. The deja vus, (and many other simple partials that have been recorded this way) were not the main point of the procedure at all, and I don't think any neurosurgeon in the world would implant electrodes just to study simple partials. They pick these up, incidently, in the process of looking for the more serious seizures.

So there may be mild deja vus that are simple partials, but I can't assert that for certain. I have no EEG recording to show you.

As for experiences that are apparently the result of precognitive dreams, we should call them "Apparent Dream Precognition", not deja vus, and other non-disprovable incidents of precognition we can call "Apparent Precognition," and not deja vus.

I have had experiences different from my deja vus which I would call "Apparent Dream Precognition" and also "Apparent Precognition". I can't lump these together with the deja vus because they are distinctly different in quality, they just weren't the same thing.

The other problem that may be in play here is descriptive ability of the people reporting the experience. If you've only had a genuine one a few times they can come and go before you can overcome your surprise enough to pay attention to them. It is possible Job has had the same thing as me, but couldn't pay close enough attention to it to see that his explanation doesn't actually fit the experience at all. It was actually a long time before I started realizing certain things about them, especially that they were internally generated "feelings" that only seemed attached to the external situation. Likewise it took probably thousands of them before I sorted out why they were creating the illusion of precogition.

Terminology is important. There was a woman posting on the Epilepsy Forum once about her son's "deja vus". I had to explain to her that what she was describing wasn't deja vu's at all, but flashbacks, another fairly common but distinctly different simple partial. The term "deja vu" seemed to her to fit what he was experiencing because he had fast-changing visual hallucinations of scenes from his past: things he'd already seen, hence, she thought, "deja vu". The term sort of fits but has already been dedicated to a specific kind of experience and it's just going to prevent people from understanding one another if we apply it to anything that roughly feels like "already seen". We don't want to create a "taxonomy" where mice are a kind of subset of cats because they both have fur, four feet, tails, and sleep alot.
 
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  • #50
A deja vu is an extremely mysterious and powerful experience where your current situation suddenly seems remarkably familiar when you concurrently know it cannot be familiar. Not everyone has had a deja vu and I think that people who haven't are somewhat confused about what it's like, and maybe think they have had one. It isn't a matter of something seeming vaguely familiar, it's an overwhelming, stop-you-in-your-tracks, flood of familiarity attached to a situation you intellectually know is not one you've ever been in before. The strength of this feeling is unbelievable. It seems 20 times more familiar than anything that actually is familiar. It's distinctly unnatural feeling: the present seems like an exact repeat of itself down to the smallest detail, as if your mind had skipped back in time and was reliving a moment all over again.
I have this sort of experience happen to me a few times a year. I don't really count them, and actually rather enjoy the experience, it makes me feel 'Human'. It reminds me of some LSD experiances I have had when i was younger, except that was more the feeling of everything taking on a new meaning, rather than everything being familiar, but knowing they are not.
 
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  • #51
Anttech said:
I have this sort of experience happen to me a few times a year. I don't really count them, and actually rather enjoy the experience, it makes me feel 'Human'.
Indeed, one deja vu is an almost beautiful mysterious experience. People who have few tend to cherish them and talk about them with enthusiasm and wonder.

I used to feel the same about the few I'd had until my late 30's when I started having several a day. This escalated till I was having several an hour all day long. Unbelievably, it got worse. I started living a life of having two or three a minute all day long. What was once a cool mystery became sheer torture.
It reminds me of some LSD experiances I have had when i was younger, except that was more the feeling of everything taking on a new meaning, rather than everything being familiar, but knowing they are not.
I've never done LSD. I have a sister who did quite a bit of it and she is now a raving lunatic who hears angels talking to her and believes she is the true wife of Jesus. I don't reccomend this drug to anyone.
 
  • #52
I have had deja vu experiences most of my life which were eventually diagnosed as partial seizures. The diagnosis was confirmed by complete elimination of symptoms after treatment with anti-seizure meds.

The experience is very profound. For me, it was an intense feeling of going back to a place that I was completely familiar with, no matter where I was at. The location or the objects around me were not important, and I was completely aware of where I was, and could drive a car during the experience, for example. It was more like going to a familiar place, or, I hesitate to say, a familiar state of existence. In other words, I had the intense feeling of living in a parallel place and having a parallel existence, which I was not aware of most of the time, but was now able to "remember" briefly. It was usually accompanied by a brief feeling of fear or despair because I came to believe I am not fully conscious of what I am experiencing, or that I am missing a big part of my life, or that I have a parallel "dream" world that I keep forgetting about.

Believe me, those of you who are describing "I feel like I have been here before," without adding that it feels like a profound physical/mental/mystical experience on a par with the most extreme mental experiences of your life, are not suffering the kinds of partial seizures I did. There is no chance of mistaking it. I continue, even under medication, to have those odd feelings occasionally, but the true deja vu experiences are completely absent.

After the diagnosis, I came to understand it as a brain dysfunction. I remembered telling the doctors I talked to that I remembered the first time I ever experienced the feeling. I was in a full contact tae kwon do fight, and got "knocked out." As I came to consciousness, I had a very, very powerful deja vu experience. I now believe that my brian may have been damaged by that punch.

I also came to believe that seizures may be responsible for some of the odd belief systems in the world today. If I were not a scientist who believes that the world is made out of stuff, and that all my feelings come from the interaction of matter in my neuronal system, I might be led to believe that I was "remembering" an alien abduction. Or I might believe I was "communicating" with a higher power and start writing on stone tables.

Zooby I feel like you. They were interesting until the frequency increased in my early 50s.

Anyway, I'm glad I stumbled across this conversation and thanks for giving me a forum to tell my story.

Jim
 
  • #53
I've never done LSD. I have a sister who did quite a bit of it and she is now a raving lunatic who hears angels talking to her and believes she is the true wife of Jesus. I don't reccomend this drug to anyone.
Can happen, its not something to be toyed with.
 
  • #54
If there are milder experiences of the kind of hippocampal centered seizures that I have then they are simply milder seizures, milder deja vus. I can't, and didn't, say these don't exist. I don't know if they do. No one could say for sure. The reason being that someone like you who may have had one of these, would never be tested with depth electrodes to see if the feeling corresponds to seizure activity. Such an invasive proceedure would never be allowed just for curiosity's sake.

The people whose deja vus have been recorded by EEG were being prepped for brain surgery because of much more serious seizures that weren't responding to medication. The depth implanted electrodes were for the purpose of locating the seizure focus. The deja vus, (and many other simple partials that have been recorded this way) were not the main point of the procedure at all, and I don't think any neurosurgeon in the world would implant electrodes just to study simple partials. They pick these up, incidently, in the process of looking for the more serious seizures.

So there may be mild deja vus that are simple partials, but I can't assert that for certain. I have no EEG recording to show you.
Of course we would not go poking around a healthy brain with electrodes -but we could certainly study healthy brains with fMRI imaging. It ain't cheap, but this type of research is done pretty frequently here at my uni. I would be curious to see which brain areas, if any, increase in activity in the case of an "induced deja vu" experience such as reported after the hypnosis experiment.
 
  • #55
bioactive said:
The experience is very profound. For me, it was an intense feeling of going back to a place that I was completely familiar with, no matter where I was at. The location or the objects around me were not important, and I was completely aware of where I was, and could drive a car during the experience, for example. It was more like going to a familiar place, or, I hesitate to say, a familiar state of existence. In other words, I had the intense feeling of living in a parallel place and having a parallel existence, which I was not aware of most of the time, but was now able to "remember" briefly. It was usually accompanied by a brief feeling of fear or despair because I came to believe I am not fully conscious of what I am experiencing, or that I am missing a big part of my life, or that I have a parallel "dream" world that I keep forgetting about.
Here's a quote from the introduction to:
-Anatomical origin of deja vu and vivid 'memories' in human temporal lobe epilepsy
(Abstract linked to in an earlier post.):

"In 1876, Jackson (1931) described a 'dreamy state' occurring in certain epileptic subjects. Although aspects of the dreamy state had been recognized as early as the 10th century by an Arab physician [quoted in Pennfield and Perot (1963) and fairly extensively discussed in the mid-19th century in the French and British literature (Pritchart, 1822; Esquirol, 1838, Morel, 1860; Herpin, 1867], it was Jackson (1931) who first described clearly all its aspects speculating with amazing accuracy on its neural substrate and giving it its name..."

..."These phenomena occur withing a 'voluminous' mental state that the patient sometimes describes as 'dreamy'; hence the name. In addition, Jackson felt that a critical component of the dreamy state was a doubling of consciousness, which he termed mental diplopia: a depressed 'normal' consciousness plus a second, parasitic consciousness: the simultaneous objective consciousness of the exterior world together with the subjective consciousness of an interior world."



I'm glad you mentioned about each occurance reminding you of this "parrallel existence" you were afraid you were going to forget again when it was over. At first I had this same sense of alarm each time I entered the state of mind where I could "sense" the universe was a mere recording that could be played over and over, but I had them so often this fear of forgetting them went away and I practically lived in the "dreamy" state, so my initial alarm that I'd forget the separate but parrallel state of mind eventually waned. For the first year or so, though, I was convinced the "loop" of time would break, I'd return to normal, and all my "knowledge" that the universe was just a recording was going to fade from my consciousness. While the experience is happening it is so powerful I am not at liberty to consider it any kind of illusion.


Believe me, those of you who are describing "I feel like I have been here before," without adding that it feels like a profound physical/mental/mystical experience on a par with the most extreme mental experiences of your life, are not suffering the kinds of partial seizures I did. There is no chance of mistaking it. I continue, even under medication, to have those odd feelings occasionally, but the true deja vu experiences are completely absent.
I'm afraid that there are people who have not had this experience but who hear people talking about it and mistake what they're saying to be referring to some purely mundane experience of things seeming familiar but not being able to quite recall why. Other people I talk to who haven't had one hear what I'm saying well enough to realize that I'm describing something they have no knowledge of, and are able to respond "No, I'm sure I've never felt anything like that." Reports like Math Is Hard's of experiences that seem to have all the right features except the attention-getting intensity are impossible to say anything definite about. They could, in fact, be more contained seizure activity, but I can't say.
After the diagnosis, I came to understand it as a brain dysfunction. I remembered telling the doctors I talked to that I remembered the first time I ever experienced the feeling. I was in a full contact tae kwon do fight, and got "knocked out." As I came to consciousness, I had a very, very powerful deja vu experience. I now believe that my brian may have been damaged by that punch.
The classic cause of seizures: a head injury.
I also came to believe that seizures may be responsible for some of the odd belief systems in the world today. If I were not a scientist who believes that the world is made out of stuff, and that all my feelings come from the interaction of matter in my neuronal system, I might be led to believe that I was "remembering" an alien abduction. Or I might believe I was "communicating" with a higher power and start writing on stone tables.
The trouble with TLE is that the seizures are in the part of your brain where emotions are generated and they usually supercharge the emotional component of the seizure such that whatever you're experiencing is "backed up" with an emotion many times normal strength. As I said, when I'm actually having a deja vu I am not at liberty to question its reality.
Zooby I feel like you. They were interesting until the frequency increased in my early 50s.
Sheer torture.
Anyway, I'm glad I stumbled across this conversation and thanks for giving me a forum to tell my story.

Jim

It's too bad this thread wasn't directed to the Mind and Brain forum which is really the proper venue for your story.
 
  • #56
Math Is Hard said:
Of course we would not go poking around a healthy brain with electrodes -but we could certainly study healthy brains with fMRI imaging. It ain't cheap, but this type of research is done pretty frequently here at my uni. I would be curious to see which brain areas, if any, increase in activity in the case of an "induced deja vu" experience such as reported after the hypnosis experiment.
If the fMRI can distinguish between seizure activity and normal activity it might go a long way toward sorting this out. I don't see that the "where" of the activity would be too informative since we are just about always using the hippocampal region: we are just about always forming and accessing memories.

A more promising type of scan might be something done with a SQUID, I think:

http://whatis.techtarget.com/definition/0,,sid9_gci816722,00.html

I have no information on how deeply into the brain this can sense, though, nor the cost of using it.
 
  • #57
zoobyshoe said:
Here's a quote from the introduction to:
-Anatomical origin of deja vu and vivid 'memories' in human temporal lobe epilepsy
(Abstract linked to in an earlier post.):


..."These phenomena occur withing a 'voluminous' mental state that the patient sometimes describes as 'dreamy'; hence the name. In addition, Jackson felt that a critical component of the dreamy state was a doubling of consciousness, which he termed mental diplopia: a depressed 'normal' consciousness plus a second, parasitic consciousness: the simultaneous objective consciousness of the exterior world together with the subjective consciousness of an interior world."

Yes, this is describing something like my experience, Especially the term "parasitic consciousness." I feel like the parallel consciousness is going on all the time without me being aware of it, which is frustrating because I feel it is something important.

I also have a feeling of it being exhausting because the parasitic consciousness involves relentless activity and effort to overcome great obstacles. During an event I am "aware" that I am undergoing all these difficulties in addition to, and in parallel with all the difficulties of my normal life.

All this sounds very Castaneda-ish but in reality I know that it is just brain damage causing perceptual changes. Having taken acid myself I know that it is entirely biological and even odder perceptual changes can occur just through stimulation of certain receptors in the brain.

Thanks for the quote.
 
  • #58
bioactive said:
All this sounds very Castaneda-ish but in reality I know that it is just brain damage causing perceptual changes. Having taken acid myself I know that it is entirely biological and even odder perceptual changes can occur just through stimulation of certain receptors in the brain.
Yes, our brains take sensory imput and organize and coordinate it into the coherent and useful experience of "normal" consciousness. Anything that interfers with this unbelievably complex neuronal activity causes corresponding distortions of our experience of the world around us, and also of ourselves.
Thanks for the quote.
You're welcome.
 
  • #59
There are many sensations associated with seizures. Fear and panic, for example. Yet, explanations for panic or fear don't involve seizures.
A seizure is not an explanation, it's random over-activity.
 
  • #60
zoobyshoe said:
If the fMRI can distinguish between seizure activity and normal activity it might go a long way toward sorting this out. I don't see that the "where" of the activity would be too informative since we are just about always using the hippocampal region: we are just about always forming and accessing memories.

A more promising type of scan might be something done with a SQUID, I think:

http://whatis.techtarget.com/definition/0,,sid9_gci816722,00.html

I have no information on how deeply into the brain this can sense, though, nor the cost of using it.
Wow - a SQUID?! At first I thought you were pulling my tentacle, but I am going to ask my profs about this. Indeed, one of the things that was mentioned in my last class is how difficult some processes are to "subtract out" with the use of a control task -- namely, neuron firing in the hippocampal regions since this is in action every moment.
What would be interesting to see is if a hypnotically induced deja vu could produce any significant firing in that region over and above normal activity. Could the hypnotic suggestion instigate an over-firing, or a mis-fire in the region, or possibly even produce a small seizure in subjects who were prone to it? If we saw nothing then we would be more inclined to believe that the subjects were just being overly cooperative in their reports.
With fMRI, we can see physical responses of neurons quieting when the subject uses CBT techniques. Subjects with depression, for instance, can settle down frontal lobe activity when an attack comes on. It seems possible that a person could also activate firing in a region through something like a hypnotic suggestion.

I am just bouncing ideas off you.

What I am also curious about is if the brain stimulation that caused the deja vu reports in epileptic patients triggered an actual uncontrolled seizure or if it was just creating a controlled inappropriate firing that would not have otherwise occurred.
 
  • #61
Math Is Hard said:
Wow - a SQUID?! At first I thought you were pulling my tentacle, but I am going to ask my profs about this.
Hehehe. I thought you'd think I was joking. However the SQUID is a genuine, if amusingly named, device.
Indeed, one of the things that was mentioned in my last class is how difficult some processes are to "subtract out" with the use of a control task -- namely, neuron firing in the hippocampal regions since this is in action every moment.
I saw a lecture where a grad student presented the thalamus as the probable origin of auditory hallucinations in schizophrenic patients because all her pet scans of hallucinating schizophrenics showed the thalamus to be the only universally active part of the brain in all the scans. Of course she had her head up her behind because the thalamus is a kind of Grand Central Station in the brain and all sensory imput is channeled through it. It is always going to be at work, unless you're in a coma.
What would be interesting to see is if a hypnotically induced deja vu could produce any significant firing in that region over and above normal activity. Could the hypnotic suggestion instigate an over-firing, or a mis-fire in the region, or possibly even produce a small seizure in subjects who were prone to it? If we saw nothing then we would be more inclined to believe that the subjects were just being overly cooperative in their reports.
I am not too interested at this point in sorting out what happened to the subjects in that study because it completely ignores what should be everyone's first suspect in any report of a deja vu: the already documented one.

There is a serious and unnecessary problem going unaddressed which was mentioned in your second link:

In some severe cases it can be distressing to the point of causing depression and some sufferers have been prescribed anti-psychotic medication.

However, experts suspect that many people who experience the sensation are unwilling to discuss it with their doctor.

In other words, people who might have this taken care of rather quickly by a neurologist prescribing anti-epileptic drugs are, instead, suffering for years because no one knows, or will acknowledge, this is seizure activity. This cause has to become well known and understood before we start tinkering around in more or less pointless speculation about other possible alternatives to explain non-problematic experiences 97% of the population seems to have once in a great while. Some anti-psychotic medications and also anti-depressents make seizures worse, but they'll be continued to be given to these people because psychiatrists and GP's and the people out there depressed and bewildered because they're having them chronically have never heard the deja vu is a completely treatable kind of simple partial seizure.
What I am also curious about is if the brain stimulation that caused the deja vu reports in epileptic patients triggered an actual uncontrolled seizure or if it was just creating a controlled inappropriate firing that would not have otherwise occurred.
These were stimulated by one electrode and recorded as seizure activity by the neighboring electrodes. Any of the electrodes can be used both as passive recievers or as a means of delivery for voltage. Each electrode is exposed at graduated points along its depth as well. They are precision made, and hair thin to do the least damage upon insertion.
 
  • #62
-Job- said:
There are many sensations associated with seizures. Fear and panic, for example. Yet, explanations for panic or fear don't involve seizures.
A seizure is not an explanation, it's random over-activity.
I'm not sure what you're trying to say, but the simple partials that manifest as fear or panic are notable in that these emotions happen in the absense of any percievable cause. The suffer can find nothing in his mind or environment to justify the inexplicable, extreme emotions.

Here is an example reported in the book Seized:

"On another typical day, at four o'clock, Jill was alone in her office. The day's interviews done, she sat reviewing her notes. Suddenly, she couldn't concentrate. The words she was reading held no meaning for her. She went back over the last few lines in vain. Something far more powerful than her notes was on her mind, 'an awful feeling of absolute panic and fear.' For no apparent reason, she felt certain that 'something really bad' was about to happen. This global, nonspecific terror imobilized her, demanding all the energy and concentration she had. It seemed to come from somewhere deep inside her where she could not reason with herself. Even though the terror was without external basis, she experienced it as though it were utterly justified and true.

This panic, she knew, was a seizure, something like the dread van Gogh occasionally felt. Her doctors had explained to her that epileptic discharge in the part of her brain that controls fear can cause a panic attack. Unfortunately, her knowledge that the feeling is really a seizure does not lessen the intensity of the experience. Each time it happens it feels horrifically real; the seizure presents itself as actual, impending doom. If one of these panic attacks were to last longer than a few hours, she believes, she would have no choice but to kill herself."

-Seized by Eve LaPlante, Pages 55-56
Harper Collins, NY 1993

Most libraries I've checked seem to have this book if you're interested in reading in great detail about Temporal Lobe Epilepsy
 
  • #63
The Chinese Explanation of Deja Vu

I once told my landlady, who is Chinese, about my deja vu's. She knew what I was talking about, and said that in her culture the explanation for this is as follows:

When a person dies they go to a place of waiting, where they prepare to be reborn in a new life and body. During this time each person is given a "cup of forgetfullness" to drink so that they will not remember their past life in their new one. Everyone is cautioned to drink every last drop of the cup of forgetfullness. Some people, though, are careless and don't drink every last drop. As a result, when they're reborn in their new life, they get small flashes of memory from the past life.
 
  • #64
zoobyshoe said:
In other words, people who might have this taken care of rather quickly by a neurologist prescribing anti-epileptic drugs are, instead, suffering for years because no one knows, or will acknowledge, this is seizure activity.

I agree. In my case, if I had not been very energetic and precise in describing my experience, the neurologist might not have identified it as partial seizure. The MRI was negative. We decided to try the anti-seizure medication diagnostically. Since the deja vu experiences ceased after treatment with Depakote, a diagnosis of partial seizures was confirmed.

Many less communicative people unwilling to discuss the details of the experience would not have made it as far as I did with the doctors.

Jim
 
  • #65
zoobyshoe said:
I'm not sure what you're trying to say, but the simple partials that manifest as fear or panic are notable in that these emotions happen in the absense of any percievable cause. The suffer can find nothing in his mind or environment to justify the inexplicable, extreme emotions.

Here is an example reported in the book Seized:

"On another typical day, at four o'clock, Jill was alone in her office. The day's interviews done, she sat reviewing her notes. Suddenly, she couldn't concentrate. The words she was reading held no meaning for her. She went back over the last few lines in vain. Something far more powerful than her notes was on her mind, 'an awful feeling of absolute panic and fear.' For no apparent reason, she felt certain that 'something really bad' was about to happen. This global, nonspecific terror imobilized her, demanding all the energy and concentration she had. It seemed to come from somewhere deep inside her where she could not reason with herself. Even though the terror was without external basis, she experienced it as though it were utterly justified and true.

This panic, she knew, was a seizure, something like the dread van Gogh occasionally felt. Her doctors had explained to her that epileptic discharge in the part of her brain that controls fear can cause a panic attack. Unfortunately, her knowledge that the feeling is really a seizure does not lessen the intensity of the experience. Each time it happens it feels horrifically real; the seizure presents itself as actual, impending doom. If one of these panic attacks were to last longer than a few hours, she believes, she would have no choice but to kill herself."

-Seized by Eve LaPlante, Pages 55-56
Harper Collins, NY 1993

Most libraries I've checked seem to have this book if you're interested in reading in great detail about Temporal Lobe Epilepsy

I meant that, possibly, if we knew as much about fear as we do about deja vu, we might be saying that fear is caused by a partial seizure.
 
  • #66
bioactive said:
I agree. In my case, if I had not been very energetic and precise in describing my experience, the neurologist might not have identified it as partial seizure. The MRI was negative. We decided to try the anti-seizure medication diagnostically. Since the deja vu experiences ceased after treatment with Depakote, a diagnosis of partial seizures was confirmed.
I like to refer people to this study:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3137487&dopt=Abstract

when the issue of diagnosis of simple partials arises. It is often not possible to get EEG or MRI confirmation of any problem. Depth implanted electrodes would resolve the issue, but this is much too invasive for mere diagnostic purposes. Your doctor took the only proper alternative in light of the fact your symptoms walked, talked, and quacked like a simple-partial: simply try an AED and see if it works.

Many less communicative people unwilling to discuss the details of the experience would not have made it as far as I did with the doctors.
There was a tragic person who used to post on the Epilepsy form who was institutionalized for seven years as a schizophrenic before someone figured out she was having complex-partial seizures. I hate thinking about this.
 
  • #67
Almost forgot the horror story part of my tale.

My neurologist, unable to find any clear physical evidence of brain trauma, and knowing that I had never been in a state of unconciousness, and knowing that the medication was preventing further seizures, nonetheless turned me into the California drivers license office.

When I asked him why, he said he didn't think I was a risk at all, but that if I did happen to have an accident, he could be sued for not reporting me. He stated that he was doing it only for his own protection. At least he was honest with me.

I ended up having to do phone interviews with an officer, and then do a drivers test like a high school student getting their first licence. Both I and the officer that tested me thought it was a silly waste of time.

Imagine the costs to the state, not to mention my lost productivity at work while jumping through these hoops.
 
  • #68
do dejavus occur through dreams!?
 
  • #69
bkvitha said:
do dejavus occur through dreams!?
This is hard to sort out. During all of my deja vu's (thousands of them) two or three stood out from all the rest because as soon as they started I was certain the reason the situation seemed familiar was because I had dreamed about it at some time in the previous few weeks. In all other respects these experiences were the same as the kind I usually had. The difference was that, for some reason, I suddenly "remembered" I had dreampt it. I put "remembered" in quotes because I suspect this is some kind of illusion, a false memory, created on the spot. The dreams I'm "remembering" probably never happened.

Neurologist Wilder Pennfield got exited when he discovered that stimulating the temporal lobes of epileptics with tiny voltages could elicit vivid memories of their past. He concluded, at first, this meant all of our memories were stored in the brain and could be retrieved. It turned out later that most of these snatches of "memory" couldn't be linked to real events in the person's past. They seemed to be improvised around real events and people but were things that had never actually, specifically happened. In addition this "memory retrieval" by electrical stimulation couldn't be reproduced in non-epileptics.

That's why I suspect these deja vu's that seem to be recollections of dreams are probably false memories, though I haven't had that particular addition to my deja vu's often enough to sort it out as well as the other things, like the illusion of precognition.
 
  • #70
zoobyshoe said:
This is hard to sort out. During all of my deja vu's (thousands of them) two or three stood out from all the rest because as soon as they started I was certain the reason the situation seemed familiar was because I had dreamed about it at some time in the previous few weeks. In all other respects these experiences were the same as the kind I usually had. The diffe: t. I put "remembered" in quotes because I suspect this is some kind of illusion, a false memory, created on the spot. The dreams I'm "remembering" probably never happened.


To tell you the truth, I've experienced so many of them, through "dreams".

I clearly know that i dreamnt it only a few weeks or months before it occured.

Yeah, maybe it is just false memory.
But how is that sometimes i just "seem" to know the answers for somethings i am really unfamiliar about...?
:bugeye:
Could it be intuition!?
 

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