Everyone must of had that feeling of Deja Vu before?

[richnfg]

Hello.
This has been a topic on my mind for a very long time now and I thought I would share my ideas here in hope for some feedback. (Note: I'm not sure if this is in the correct section, please move, if necessery!) I am not jumping to any conclusions here but just wanted to express an idea!

Everyone must of had that feeling of Deja Vu before? The feeling where you think you have seen a certain scenario before (I have had it once that I could even finish what the person speaking to me was saying just because of this "Deja Vu" feeling.
This all depends on my understanding of higher dimensions, but I think if you live in 5 dimensions (we live in 4) then you can freely move through time and what I am getting at is if Deja Vu experiences may simply be leaks from higher dimensions? Could you somehow be absorbing this information leak from a higher dimension subcontiously and then when it comes to that time that is the reason for this Deja Vu feeling?

I really have no idea how this would work but I was wondering if anyone knew anything more about this or has any comments. It has been on my mind for a while now!

Thanks, Rich

 

[Pythagorean]

I'd always assumed deja vu was just a sense of familiarity of the characteristics of the situation, and not so much an actual sharing of two different times.

That is, It's largely a psychological phenomena, rather than one of time or space.

 

[richnfg]

Hmmm...yes. But what about them times where you just know its been exactly the same before? Surely that's a little more than familiar with the situation. But then, I guess, that can be down to personal experience.

 

[Pythagorean]

Hmmm...yes. But what about them times where you just know its been exactly the same before? Surely that's a little more than familiar with the situation. But then, I guess, that can be down to personal experience.

People tend to think they 'know' things a lot. The people that 'knew' everything over the ages have asseted that: the Earth was flat, Earth was the center of the universe, flight was impossible, and a thing like TV could never be invented.

That's one of the major issues of science. Seperating what you 'know' from what you can observe and measure repeatedly.

I've never had the experience, and I'd have to admit I'm skeptical. It sounds like something I would have came up after smoking a joint in high school.

 

[selfAdjoint]

I think this thread should be on the Skepticism and Debunking board, so I am going to transfer it there.

 

[Math Is Hard]

I'd always assumed deja vu was just a sense of familiarity of the characteristics of the situation, and not so much an actual sharing of two different times.

That is, It's largely a psychological phenomena, rather than one of time or space.

I'd categorize it as a neurological phenomenon. There was a discussion about it here:
https://www.physicsforums.com/showthread.php?t=90814

 

[waht]

I used to have deja-vu a lot especially in my teen years. I was absolutely convinced I had a vision couple seconds into the future. But as much as I'd like to believe, this phenomena is actually a glitch in the brain caused by mini-seizures.

Well that's the current psychological explanaton.

 

[Ivan Seeking]

I realize that Zooby is well read on the subject of simple partial seizures, but the supporting evidence for the statements in the linked thread is pretty thin. A few references beyond a drug site would be nice.

Also, does this account for all experiences? If I walk into a room and have a sense of deja vu, and later I remember that I was once there as a small child, have I experienced a simple partial seizure? Clearly there are other reasons why one might have a feeling like this. And here is another problem with this sort of thing: If I feel a breeze on my arm or hear a buzzing sound, it may be a breeze or a buzzer, or it may be a simple partial seizure, but the existence of simple partial seizures does not exclude the existence of wind or buzzers.

 

[Math Is Hard]

Most of what I read about it links it to the temporal lobe region near the hippocampal formations. I definitely am not that knowledgeable about it since I am more interested in parietal lobe functions and focus most of my studying there. Would I say that a mini-seizure in this region explains all experiences? Probably not. But there does seem to be some evidence of at least a single dissociation for the phenomenom:
http://pn.psychiatryonline.org/cgi/content/full/39/22/25

Dèjá vu experiences are a common feature of temporal lobe seizures and have often been reported after stimulating healthy subjects' medial temporal lobes. Such evidence suggests that the middle area of the temporal lobes gives rise to such experiences.

 

[-Job-]

I've identified that i get the feeling of Deja Vu, for example, in the following scenario:
- at one point i see an object, like a toothbrush, and i think of something, or the toothbrush reminds me of something.
- later on, if i see the same object and think the exact same thing, i get the feeling of Deja Vu,.

I think the reason sometimes the feeling is hard to explain is because either the first or, more likely, the second thought might happen unconsciously, as a reflex, so you might not be aware of what triggered the feeling.
For example, have you ever, while flipping through the pages of a book, have a word pop into your head without you ever actually seeing (or remembering seeing) the word? Whenever this happens to me i always scan the page for what might have triggered the word to get into my head. If i closely study the path my eyes followed when they moved across the page i always either find the word or some syllables, maybe in different lines, that form the word.
Similarly, in the same way the word got into my head when i was flipping through the pages, sometimes, unconsciously, maybe from seeing an object from the corner of my eye, something may trigger a thought to get into my head. If this has happened before i will get the feeling of Deja Vu. If I'm unable to identify what triggered this then i won't be able to explain it, which is common.
I'm pretty confident that this is what deja vu is, i usually pay close attention whenever i get the feeling, and i find that this explanation works for me.

 

[moose]

It's kinda weird when you get deja vu, in your dreams!

When it happens in real life, it's kinda weird. When it happens to me, I usually feel that it happened once only slightly before it actually happens (giving me no time to think)...

 

[zoobyshoe]

I realize that Zooby is well read on the subject of simple partial seizures, but the supporting evidence for the statements in the linked thread is pretty thin. A few references beyond a drug site would be nice.

You should have read the whole thread:

Actually, I just realized I could take a pic of the EEG of a deja vu and post it:

This guy has depth electrodes implanted right into various parts of his limbic system through holes drilled in his skull in an attempt to locate his seizure focus prior to epilepsy surgury.
This is from a paper called The Role Of The Limbic Sysytem in Experiential Phenomena of Temporal Lobe Epilepsy by Pierre Gloor, et. al. Annals of Neurology, Vol12 No2 August 1982

In addition, in another thread on the subject I linked to this abstract:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8149215&dopt=Abstract

Also, does this account for all experiences? If I walk into a room and have a sense of deja vu, and later I remember that I was once there as a small child, have I experienced a simple partial seizure?Clearly there are other reasons why one might have a feeling like this. And here is another problem with this sort of thing: If I feel a breeze on my arm or hear a buzzing sound, it may be a breeze or a buzzer, or it may be a simple partial seizure, but the existence of simple partial seizures does not exclude the existence of wind or buzzers.

The sensory and emotional experiences of simple partial seizures call attention to themselves for being inexplicable in normal terms. The hyperfamiliarity of a deja vu is so striking because the person can't account for it. It doesn't strike you as a memory of childhood, or anything you can point to in your past. It is weird and noteworthy for seeming like nothing but a memory of the present.

Likewise, if a simple partial causes a loud buzzing sound or feeling of a breeze, it is remarkable because there is nothing around to account for it.

Of course authentic memories, sounds, and buzzers aren't simple partial seizures.

 

[zoobyshoe]

I definitely am not that knowledgeable about it since I am more interested in parietal lobe functions and focus most of my studying there.

What interests you about the parietal lobes? Most people seem to get interested in the frontal or temporal lobes.

 

[zoobyshoe]

I've identified that i get the feeling of Deja Vu, for example, in the following scenario:
- at one point i see an object, like a toothbrush, and i think of something, or the toothbrush reminds me of something.
- later on, if i see the same object and think the exact same thing, i get the feeling of Deja Vu,.

I think the reason sometimes the feeling is hard to explain is because either the first or, more likely, the second thought might happen unconsciously, as a reflex, so you might not be aware of what triggered the feeling.
For example, have you ever, while flipping through the pages of a book, have a word pop into your head without you ever actually seeing (or remembering seeing) the word? Whenever this happens to me i always scan the page for what might have triggered the word to get into my head. If i closely study the path my eyes followed when they moved across the page i always either find the word or some syllables, maybe in different lines, that form the word.
Similarly, in the same way the word got into my head when i was flipping through the pages, sometimes, unconsciously, maybe from seeing an object from the corner of my eye, something may trigger a thought to get into my head. If this has happened before i will get the feeling of Deja Vu. If I'm unable to identify what triggered this then i won't be able to explain it, which is common.
I'm pretty confident that this is what deja vu is, i usually pay close attention whenever i get the feeling, and i find that this explanation works for me.

Job, I'm not sure that what you're describing is the experience referred to as a deja vu. It sounds more like you are actually remembering something, actually being reminded of something that you can't quite recall, but maybe could if you tried.

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.

Your description of being reminded of what you were thinking about the previous time you were looking at a toothbrush doesn't sound like an authentic deja vu to me.

 

[Ivan Seeking]

You should have read the whole thread:

I looked it over and only saw one link. The other references can't easily be verified.

Of course authentic memories, sounds, and buzzers aren't simple partial seizures.

Of course.

If there is such a thing as a genuine precognitive or similar experience, then it might also be mistaken for what you describe as deja vu.

I was struck recently by a story from a woman who, due to what was described as precognition, insisted that her husband not take one of the doomed AA flights on 911. It saved his life.

The question is not whether clinical observations and explanations for deja vu are correct. The question is whether or not there could be more to the story.

 

[Math Is Hard]

What interests you about the parietal lobes? Most people seem to get interested in the frontal or temporal lobes.

I am interested in dyscalculia and acalculia and how the symptoms can arise after left parietal lobe damage.

 

[zoobyshoe]

I looked it over and only saw one link. The other references can't easily be verified.

If you google simple partial seizures symptoms you'll find that deja vu's are mentioned in just about all lists. For the sake of ease of reading I generally just provide one link when explaining that deja vu's are simple partials. If the questioner seems naive about neurology I try to find a simpler link geared toward the layman with the least medical jargon to slog through.

Here's a link to a serious medical paper for you with all the jargon:

http://www.emedicine.com/NEURO/topic342.htm

From that link, here's a relatively comprehensive list of simple partial symptoms:

* Motor simple partial seizures

o Clonic discharges in the sensorimotor cortex cause jerky, rhythmic movements that may remain restricted to one body segment or spread by “jacksonian march.”

o Benign focal epilepsy of childhood accounts for 15-25% of childhood epilepsy and eventually remits by age 16 years.

+ Typical seizures are simple and motor, affect the face or arm, and occur soon after falling asleep or awakening.

+ As it usually remits by age 16 years, this syndrome does not always require treatment.

o Another subtype, epilepsia partialis continua (ie, Kojewnikoff syndrome), includes stereotypical periodic to semiperiodic clonic activity that may persist for years and is often refractory to treatment.

+ Clonic jerking usually involves the thumb or great toe, and may or may not spread to other body parts.

+ This activity has been associated with stroke, tumor, trauma, hypoxia, Rasmussen encephalitis, syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke (MELAS), subacute sclerosing panencephalitis (SSPE), and adult nonketotic hyperglycinemia.

o Tonic-supplementary motor area (SMA) and premotor region discharges produce sustained contractions and unusual postures of a limb.

+ In 72% of cases SMA seizures are not associated with impaired consciousness.

+ Versive-smooth or jerky, tonic contractions of head and eye muscles, usually on the side contralateral to the discharge, often are followed by a secondarily generalized tonic-clonic seizure.

+ Phonatory activation of the primary or supplementary motor cortex produces vocalizations, speech arrest, or aphasia.

* Sensory simple partial seizures

o Somatosensory-primary sensory cortex seizures usually elicit positive or negative sensations contralateral to the discharge.

o Symptoms associated with seizures from the postcentral gyrus include tingling, numbness, pain, heat, cold, agnosia, phantom sensations, or sensations of movement.

o Abdominal pain usually originates from the temporal lobe, and genital pain from the mesial parietal sensory cortex.

o The posterior parietal cortex is the likely origin of limb agnosia.

o Supplemental sensory-secondary sensory cortex seizures may have ipsilateral or bilateral positive or negative sensations or vague axial or diffuse sensations.

o Visual-calcarine cortex discharges produce elemental hallucinations including scintillations, scotomata, colored lights, visual field deficits, or field inversion.

o The visual association cortex is the probable location of origin of complex visual hallucinations and photopsias.

o Auditory SPS from the auditory cortex typically are perceived as simple sounds, rather than words or music.

o Olfactory-uncinate seizures originate from the orbitofrontal cortex and the mesial temporal area. Perceived odors are usually unpleasant, often with a burning quality.

o Gustatory seizures usually are associated with temporal lobe origin, although the insula and parietal operculum also have been implicated. Perceived tastes are typically unpleasant, often with a metallic component.

o Vestibular seizures originate from various areas, including frontal and temporal-parietal-occipital junction. Symptoms include vertigo, a tilting sensation, and vague dizziness.

o Psychic SPS arise predominantly from the temporal and limbic region, including the amygdala, hippocampus, and parahippocampal gyrus. Perceptual hallucinations or illusions are usually complex, visual or auditory, and are rarely bimodal.

+ Includes the déjà vu and jamais vu phenomena

+ Emotional: Fear is usual, but SPS can elicit happiness, sexual arousal, anger, and similar responses.

+ Cognitive: These responses include feelings of depersonalization, unreality, forced thinking, or feelings that may defy description.

* Autonomic simple partial seizures

o Abdominal sensation phenomena

+ These are common in mesial temporal epilepsy but can arise from the operculum and occipital region.

+ Symptoms include nausea, pain, hunger, warmth, and “epigastric rising” sensations, and may be associated with piloerection (ie, gooseflesh).

o Cardiovascular sensations

+ The most common cardiac manifestation of any seizure is sinus tachycardia with arrhythmias, with bradycardia occurring infrequently.

+ Some patients have chest pain or a sensation of palpitation that mimics cardiac disease.

+ Respiratory inhibition has been reported with electrical stimulation of the temporal regions.

o Pupillary symptoms - Miosis, mydriasis, hippus, and unilateral pupillary dilatation

o Urogenital symptoms

+ Seizures from the superior portion of the posterior central gyrus can result in genital sensations, while sexual auras arise more from the limbic or temporal regions.

+ Ictal orgasms have been reported, although rarely, in association with seizures arising from various cerebral locations.

o Other autonomic symptoms - Rarely perspiration, lacrimation, ictal enuresis, or flushing

* Postictal neurological deficits can occur after an SPS as a negative manifestation of the function affected by the seizure (eg, Todd paralysis).

Notice the section labeled "psychic" symptoms. Here you'll find the deja vu mentioned. (Note that the use of the word "psychic" here, means of, or pertaining to, the psyche, i.e. the mind, and shouldn't be construed to refer to anything paranormal.)

o Psychic SPS arise predominantly from the temporal and limbic region, including the amygdala, hippocampus, and parahippocampal gyrus. Perceptual hallucinations or illusions are usually complex, visual or auditory, and are rarely bimodal.

+ Includes the déjà vu and jamais vu phenomena

+ Emotional: Fear is usual, but SPS can elicit happiness, sexual arousal, anger, and similar responses.

+ Cognitive: These responses include feelings of depersonalization, unreality, forced thinking, or feelings that may defy description.

If there is such a thing as a genuine precognitive or similar experience, then it might also be mistaken for what you describe as deja vu.

I was struck recently by a story from a woman who, due to what was described as precognition, insisted that her husband not take one of the doomed AA flights on 911. It saved his life.

The question is not whether clinical observations and explanations for deja vu are correct. The question is whether or not there could be more to the story.

Once again it seems you're arguing against me without having even read what I said. I discussed this in the thread linked to by Math Is Hard with a member named Seraphim. Please read that exchange. If a person has a precognitive feeling about the future that authentically comes to pass then it is some kind of authentic precognition, and not the illusion of precognition that sometimes accompanies a deja vu. The illusion of precognition that arises from a deja vu is quite noteworthy for being innaccurate.

Back when I was having a couple hundred deja vu's a day I started making a point of noting what I was certain was going to happen next and found out I was wrong about 99% of the time despite the fact I was always completely certain I knew, the feeling I had lived through this moment already was so intensly strong.

On the other hand, and in contrast to that, I once had an anomalous experience where the situation I was in caused me to "remember" that I had literally seen this situation before, projected in front of my eyes like a movie at some point in the past. I could remember when and where that projection had taken place. This was a distinctly different experience than a deja vu. This may have been an instance of authentic precognition, I'm not sure. The regular deja vu's I used to have all the time were definitely not.

 

[zoobyshoe]

I am interested in dyscalculia and acalculia and how the symptoms can arise after left parietal lobe damage.

In that case you may be interested in a rare genetic disorder called William's Syndrome. Oliver Sacks did an hour long special on TV about it as part of a four part series on rare syndromes a few years back. People with William's Syndrome are born without the gene for elastin. In addition to the way this affects their skin, it also produces four other remarkable results. The most amazing of these is that they have superhearing and can hear a whisper a hundred feet away. Another, a deficit, is that they have no sense of the passage of time. The third is that they all seem to be extremely attracted to music and seem to experience an almost synaesthetic feeling of physical pleasure when listening to it. Alot of them learn to play musical instruments and sing, though not particularly well. The fourth, the one that would interest you, is that they are completely unable to handle numbers and math and spatial relations.

At the time this show aired they didn't know much about this syndrome and the neurologists interviewed seemed to be in the beginning stages of just sorting out the spatial and math problems trying to determine the exact extent of these. I don't know what they've found out in the meantime, but it seems a fair guess that the parietal lobes are implicated.

 

[Math Is Hard]

In that case you may be interested in a rare genetic disorder called William's Syndrome. Oliver Sacks did an hour long special on TV about it as part of a four part series on rare syndromes a few years back. People with William's Syndrome are born without the gene for elastin. In addition to the way this affects their skin, it also produces four other remarkable results. The most amazing of these is that they have superhearing and can hear a whisper a hundred feet away. Another, a deficit, is that they have no sense of the passage of time. The third is that they all seem to be extremely attracted to music and seem to experience an almost synaesthetic feeling of physical pleasure when listening to it. Alot of them learn to play musical instruments and sing, though not particularly well. The fourth, the one that would interest you, is that they are completely unable to handle numbers and math and spatial relations.

At the time this show aired they didn't know much about this syndrome and the neurologists interviewed seemed to be in the beginning stages of just sorting out the spatial and math problems trying to determine the exact extent of these. I don't know what they've found out in the meantime, but it seems a fair guess that the parietal lobes are implicated.

Thanks for the tip. I would not have thought about looking at William's syndrome in relationship to this. I remember reading about children with WS in a biology class and I was struck by their similar physical appearance (they look like pixies). I do remember reading that they had severe learning and developmental disabilities, but didn't know much about the nature of them. So your hunch may be right. I found this article:
Evidence for superior parietal impairment in Williams syndrome.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15642924

Parietal lobe impairment is hypothesized to contribute to the dramatic visual-spatial deficits in Williams syndrome (WS). The authors examined the superior and inferior parietal lobule in 17 patients with WS and 17 control female adults (CNLs). The right and left superior parietal lobule gray matter volumes were significantly smaller in patients with WS than in CNLs, even after controlling for total cerebral gray matter. Impaired superior parietal function could explain WS visual-spatial and visual-motor problems.

Unfortunately I wasn't able to read the entire article and find out if there were any significant differences found in the inferior parietal lobule which is supposed to very important for manipulation of numbers.

I've also read about a peculiar disorder called Gerstmann Syndrome.
http://en.wikipedia.org/wiki/Gerstmann_syndrome
It's really odd because one of the symptoms is inability to recognize one's own fingers, but it goes along with dyscalculia, dysgraphia, and left-right orientation. One of the theories about the finger agnosia/dyscalculia connection is that early learning of math concepts is strongly tied to finger-counting.

What I have found really compelling are cases where adults lose different math abilities due to stroke or brain injury, and it seems to be consistently occurring with left parietal lobe damage. I was thinking about starting a thread on this topic, but I don't know how many people would be interested.

But back to Deja Vu...

 

[zoobyshoe]

Thanks for the tip. I would not have thought about looking at William's syndrome in relationship to this. I remember reading about children with WS in a biology class and I was struck by their similar physical appearance (they look like pixies). I do remember reading that they had severe learning and developmental disabilities, but didn't know much about the nature of them. So your hunch may be right. I found this article:
Evidence for superior parietal impairment in Williams syndrome.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15642924

Unfortunately I wasn't able to read the entire article and find out if there were any significant differences found in the inferior parietal lobule which is supposed to very important for manipulation of numbers.

I've also read about a peculiar disorder called Gerstmann Syndrome.
http://en.wikipedia.org/wiki/Gerstmann_syndrome
It's really odd because one of the symptoms is inability to recognize one's own fingers, but it goes along with dyscalculia, dysgraphia, and left-right orientation. One of the theories about the finger agnosia/dyscalculia connection is that early learning of math concepts is strongly tied to finger-counting.

What I have found really compelling are cases where adults lose different math abilities due to stroke or brain injury, and it seems to be consistently occurring with left parietal lobe damage. I was thinking about starting a thread on this topic, but I don't know how many people would be interested.

But back to Deja Vu...

Dr. Bellugi, one of the authors of the WS article you linked to, was the main neurologist Sacks interviewed in his TV special about it. She did a lot of tests on a little girl named Heidi. In one, Heidi was asked to copy the arrangement of 5 or 6 wood blocks. They were a mix of cubes and rectangular ones. Heidi seemed completely unable to grasp the original arrangement, and couldn't reproduce it with the second identical set they gave her. In another scene they showed Heidi a dozen cinammon buns on a plate and asked her to count them. This she could do by pointing to each one and counting aloud as she went along. Then they covered all but three of the buns with a cloth and asked her how many there were on the plate. She counted three. They reminded her that the ones under the cloth were still there. Still, she insisted there were only three buns on the plate.

I was personally confused about what kind of deficit this latter demonstration indicated, but it was clear that the covered buns somehow ceased to exist for her when she couldn't see them.

The inability to recognize the fingers in Gerstmann Syndrome sounds like a proprioceptive deficit, which I've always read to be associated with parietal problems. My brother-in-law who has MS cannot sense the position of his feet. He has to watch them when he walks to know where they are. Some people have simple partials where their proprioceptive "knowledge" of various body parts shuts off, and they are startled by the sight of their own limbs, the limbs don't feel like they belong to them.

The theory that agnosia for the fingers could lead to math deficits sounds pretty logical to me. I still count on my fingers.

 

[Ivan Seeking]

Once again it seems you're arguing against me without having even read what I said.

AFAIK I'm not arguing against you, and I haven't had the time to read everything. I was just making a point relevant to this forum.

In cases you didn't read it, the first thing that I did was to point out that you are well read on the subject.

 

[-Job-]

Job, I'm not sure that what you're describing is the experience referred to as a deja vu. It sounds more like you are actually remembering something, actually being reminded of something that you can't quite recall, but maybe could if you tried.

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.

Your description of being reminded of what you were thinking about the previous time you were looking at a toothbrush doesn't sound like an authentic deja vu to me.

That may be the case, i can't say I've ever had such an overwhelming feeling of deja vu as you described, but it has happened before. For example, i remember, when i was into collecting Magic The Gathering cards, buying a pack which contained a particular card and feeling that me being in that place (an alley) looking at that card had happened before, though i was very confortable that that couldn't be the case (it was my second/third pack and i had never seen the card before in my life). With the toothbrush, i initially had the feeling that what was happening had happened before, and it felt like Deja Vu until i understood that the reason was because the thought process triggered by the toothbrush was exactly the same as it had happened once before. It seemed very clear cut and i said to myself "ah, so that's why that happens".

 

[zoobyshoe]

That may be the case, i can't say I've ever had such an overwhelming feeling of deja vu as you described, but it has happened before. For example, i remember, when i was into collecting Magic The Gathering cards, buying a pack which contained a particular card and feeling that me being in that place (an alley) looking at that card had happened before, though i was very confortable that that couldn't be the case (it was my second/third pack and i had never seen the card before in my life).

This sounds like a deja vu the way you've described it. But when you go on to explain it being like this:

With the toothbrush, i initially had the feeling that what was happening had happened before, and it felt like Deja Vu until i understood that the reason was because the thought process triggered by the toothbrush was exactly the same as it had happened once before. It seemed very clear cut and i said to myself "ah, so that's why that happens".

it doesn't sound like a deja vu any more, but an authentic memory. The second experience had simply reminded you of the first. In other words, the reason it seemed familiar is because it was familiar. With a deja vu the whole weirdness and mystery arises from the fact that it is actually not familiar at all, you're sure of this, yet it feels superfamiliar, more familiar than anything you actually know to be familiar.

If you look at the EEG tracing of the patient having a deja vu I posted you can see how radically the neuronal activity jumps when it starts. It is this avalanche of unprovoked neuronal firing in the part of the brain that governs memory that accounts for the power and inexplicablness of the experience. The feeling that you're experiencing a memory when you actually arent is falsely and intensly generated from within the brain. It seems it must have something to do with the situation around you, but it actually doesn't at all, which is why a person can never figure out why the present should seem so remarkable familiar.

 

[-Job-]

This sounds like a deja vu the way you've described it. But when you go on to explain it being like this:


it doesn't sound like a deja vu any more, but an authentic memory. The second experience had simply reminded you of the first. In other words, the reason it seemed familiar is because it was familiar. With a deja vu the whole weirdness and mystery arises from the fact that it is actually not familiar at all, you're sure of this, yet it feels superfamiliar, more familiar than anything you actually know to be familiar.

If you look at the EEG tracing of the patient having a deja vu I posted you can see how radically the neuronal activity jumps when it starts. It is this avalanche of unprovoked neuronal firing in the part of the brain that governs memory that accounts for the power and inexplicablness of the experience. The feeling that you're experiencing a memory when you actually arent is falsely and intensly generated from within the brain. It seems it must have something to do with the situation around you, but it actually doesn't at all, which is why a person can never figure out why the present should seem so remarkable familiar.

The only difference between the toothbrush and the card, that i can identify, was that with the toothbrush i came to an explanation. Perhaps the proper definition of Deja Vu does not involve finding out what caused the feeling, but the neuronal activity has to be triggered by something. Judging from the neuronal activity would you say the possiblity of it having been triggered by a memory is out of the question? I would say a memory is not unlikely to be the trigger. There can be some subtleties in an environment that when combined bring up a memory. Maybe in the past i have been in a place with blue walls, right before going to work, with a man humming a Beatles song, and i start to think about the Beatle's song "A hard day's night" which leads me to think about my dog and that funny she did recently. These things will be weakly related into a memory.
If in the future without noticing I'm in a place with blue walls, hearing any beatles song, and for some reason, any at all, i start to think about my dog, and that funny thing she once did, then these things can trigger that weak memory. But i won't be aware of the memory because it's not the same place, it only has blue walls, it's not the same beatles song, it's just a beatles song, and it's not the same thought process, it just begins and ends the same. All of this can trigger a memory and yet it maybe impossible for me to identify why the situation seems familiar. Why would it be the blue walls and not ceiling fan? There are many details, how can i identify the ones that triggered the memory? Many times we can't, and we're just left with the feeling of familiarity, Deja Vu. Whether or not neuronal activity is triggered by this is open for debate, but if i have experienced deja vu I'm confient that it is, although i admit the possibility that i never experienced proper deja vu (even though i have no reason to believe that)

 

[zoobyshoe]

The only difference between the toothbrush and the card, that i can identify, was that with the toothbrush i came to an explanation. Perhaps the proper definition of Deja Vu does not involve finding out what caused the feeling, but the neuronal activity has to be triggered by something. Judging from the neuronal activity would you say the possiblity of it having been triggered by a memory is out of the question?

Compare this small seizure in the part of the brain that governs memory to the full body convulsions of a Grand Mal seizure. Is it possible the grand mal convulsions were triggered by actually moving the muscles? That's what you're asking me.

 

[-Job-]

That's not true. You're making the assumption that, as with a Grand Mal seizure, this "small seizure" activity correlated with Deja Vu is random and caused by abnormal functioning of the brain. Should we make that assumption for every "small seizure"? Where does normal activity end and a "small seizure" begin? What brain process can't be correlated to a "small seizure"? Does sex generate a small seizure in certain areas of the brain? Is this brain activity abnormal and uncaused or at least with a cause not identifiable by the subject?

 

[zoobyshoe]

That's not true. You're making the assumption that, as with a Grand Mal seizure, this "small seizure" activity correlated with Deja Vu is random and caused by abnormal functioning of the brain. Should we make that assumption for every "small seizure"?

Yes, this kind of hypersynchronous firing is not normal and the result is a distorted experience just like muscular seizures represent distorted, abnormal muscular activity.

http://www.emedicine.com/neuro/topic415.htm

Seizures are the manifestation of abnormal hypersynchronous discharges of cortical neurons.

and:

Seizures are paroxysmal manifestations of the electrical properties of the cerebral cortex. A seizure results when a sudden imbalance occurs between the excitatory and inhibitory forces within the network of cortical neurons in favor of a sudden-onset net excitation.

Where does normal activity end and a "small seizure" begin?

First off: a "small" seizure, that is: a simple partial seizure, is small only in that it is limited to a small part of the brain. The actual activity of the smaller number of neurons involved during a simple partial is just as pathological as during a full brain seizure. They aren't seizing more gently or anything like that. There is a definite threshold that is crossed when the neurons begin to fire both more strongly than normal and provoke nearby neurons to do the same. The paper I linked to above goes into the technical details of this if you want to slog through it with a medical dictionary.

What brain process can't be correlated to a "small seizure"?

You don't seem to understand that the firing of neurons is not a seizure. A seizure is a particular kind of abnormal, exaggerated and uncontrolled firing of neurons. This can happen anywhere in a persons brain, or to just about the whole brain at once. It is always disruptive and causes malfunctioning of the brain processes affected.

We percieve everything around and in us by virtue of the smooth, proper functioning of our brains. We percieve, think and feel and plan with our brains. When some small or large population of neurons begins to malfunction for any reason, be it seizure, stroke, Multiple Sclerosis, Parkinson's, Alzheimer's, or any brain disease, a person's perceptions, thought processes, emotions, and body functions can be grossly distorted, exaggerated, or stop functioning altogether.

Does sex generate a small seizure in certain areas of the brain?

Good question. This came up in a thread on an Epilepsy forum once. Is the activity of the parts of the brain responsible for things like orgasms and sneezes anything like seizure activity? Everyone's intuition about it was that things like this seemed to have the same kind of intensity. No one bothered to research it, though, and we left it at wondering.

I'd say there are some obvious important differences. Sneezes and orgasms are provokable in perfectly healthy people by stimulating the right sensory organs. There is no built in, natural way to provoke a seizure in a healthy person (memories don't cause deja vu's, moving the muscles doesn't cause convulsions). Sneezes and orgasms serve a purpose and they are self limiting.

The other thing that came up is hiccups. These are more suspect. They are often not self limiting, seem to go out of control, and they don't seem to serve a purpose.

Is this brain activity abnormal and uncaused or at least with a cause not identifiable by the subject?

Seizure activity is always abnormal and there's always a cause: it's always a symptom that something else is wrong. (Seizures are not a disease unto themselves.) There is always some lesion or chemical problem or oxygen starvation or something that causes it. The paper I linked to in my post to Ivan about simple partials has a list of some common causes:

Causes: Any localized structural lesion of the brain can result in SPS, including the following:

* Developmental abnormalities

* Vascular lesions

* Meningitis/focal encephalitis

* Trauma

* Tumors

* Hypoxic insults

* Postsurgical changes

* Metabolic and electrolyte shifts

* Endocrine disorders

* Medications and toxins

Note especially, "Metabolic and electrolyte shifts". This sort of thing can happen to anyone as a result of being overstressed, overtired, poorly nourished, dehydrated, etc. Notice also "Endocrine disorders". Your endocrine system is quite complex and anything that throws it out of whack might predispose you to a temporary bout with simple partials. Anyone might have a simple partial, or a few of them, without there being anything permanently or seriously wrong with them.

 

[zoobyshoe]

If in the future without noticing I'm in a place with blue walls, hearing any beatles song, and for some reason, any at all, i start to think about my dog, and that funny thing she once did, then these things can trigger that weak memory. But i won't be aware of the memory because it's not the same place, it only has blue walls, it's not the same beatles song, it's just a beatles song, and it's not the same thought process, it just begins and ends the same. All of this can trigger a memory and yet it maybe impossible for me to identify why the situation seems familiar. Why would it be the blue walls and not ceiling fan? There are many details, how can i identify the ones that triggered the memory? Many times we can't, and we're just left with the feeling of familiarity, Deja Vu. Whether or not neuronal activity is triggered by this is open for debate, but if i have experienced deja vu I'm confient that it is, although i admit the possibility that i never experienced proper deja vu (even though i have no reason to believe that)

I see you added to this post after I responded so I'll address your addition.

What you're describing with the memory that you can't place is not a deja vu. It's just a memory you can't place. Everyone has had this experience: you are unconsciously reminded of something by some subliminal trigger you're not aware of.

I have had this problem before: if someone hasn't actually had a deja vu they assume I'm talking about this sort of vague memory. I find it's impossible to communicate what they're really like to someone who's never had one and the people who've never had one sometimes think they have because of the kind of thing you're talking about. Sometimes I'll be watching a movie on TV and I'll suddenly be struck by the strange feeling that it seems familiar even though I'm not aware of having seen it before. Then later I'll suddenly remember that I did see part of it once several years before but changed the channel out of boredom. This is not a deja vu. Likewise I once was overwhelmed by an amazingly pleasant sense of familiarity when I was in a friend's garage and bent down to pick a wrench up off the floor. For some reason some rusty old cans on the floor smelled exactly like the old tools in my grandmother's tool shed and it reminded me of a whole period in my childhood I hadn't thought about in a long time. It took me a while to place the smell, though. I couldn't remember at first where I'd smelled it before. This was a powerful experience, yes, but it was nothing like a deja vu. And, of course, it wasn't a seizure, just a memory.

A deja vu is quite different. You have the distinct feeling your life is a recording that is being played over again. Everything around you down to the smallest detail seems superfamiliar. You don't feel merely reminded of something you can't put your finger on. You know what is familiar: everything! All the things around you and every thought in your head. Your life seems like a recording that has been rewound a moment and is being replayed with your memory of the previous playing intact.

Still, even that doesn't do the experience justice because if you repeat a song on a CD, for instance, the second playing doesn't amaze you for being familiar. A deja vu does: everything seems superfamiliar, and that fact amazes you. If you happen to speculate about what might happen next, that speculation seems amazingly familiar, and you suddenly believe this is because you know what is going to happen next. If it doesn't happen, the fact it didn't happen seems amazingly familiar, and you say to yourself: "Oh yeah! I made that same mistake about what was going to happen next the last time I lived through this time loop!" No matter what happens it all gets dosed with the same superfamiliarity.

I have talked to many people who've had the same experience of a deja vu that I'm describing, and it was clear from everything they said that we were talking about the same thing. There is generally a ramping up of emotion when they talk about it, an increase in exitement, because it is such a mind-blowing, unforgettable experience. However, you can't gage this sort of thing over the internet and I'm starting to wonder if everyone who reports they've had a deja vu has actually had one.

 

[-Job-]

I know what you're saying Zoob, but the way you're putting is not the way it's interpreted. It doesn't feel like a memory, like as what you described with the movie and the smell. It's not about something concrete seeming familiar, it's the impression that the situation has happened before. When i mention familiarity, I'm just suggesting that it's unconsciously triggered by some familiarity with the situation, that it's caused by this familiarity, even though you're not aware of anything concrete seeming familiar.
For example, recently before i went to bed there was a mosquito in my room, i can't sleep if there is a mosquito in the room. I had seen it but i didn't know where it was so in my attempt to move it from its hiding place i started to move things. I eventually came to my bed and shook the bed sheets, then looked at the floor in front of the bed and while doing this i had the feeling of Deja Vu, namely that this exact same thing had happened before, namely me being there doing the exact same thing for exactly the same reason. It's a familiarity with the sequence of input-thought-reaction, i.e. the situation, not with anything concrete.
I think this is what the majority of the people, who claim to have experienced Deja Vu, experience, which is possibly not the "clinical Deja Vu" that you mentioned and that is associated with a small seizure.
I think i'll leave it at that.

 

[Math Is Hard]

Can the deja vu experience vary in intensity or how long it lasts? I think there were a couple of times I had deja vu and it was just a vague feeling of familiarity lasting for a split second. I have also had a longer deja vu feeling that I've had during a conversation with someone. I know it lasted longer because I was analyzing the experience while I was talking, and I was telling the person I was having deja vu and felt I had had that conversation with her before.

 

[-Job-]

I think if you were to analyze the conversation, possibly, you'd find that the familiarity you experienced was triggered by some aspects of the conversation (i.e. the line of reasoning, not necessarily the wording).
When a situation causes a subject to consider A and B, and conclude A + B => C, it's not a wild assumption that the brain will associate A and B with C. If a situation comes up that leads a subject to consider A + B = C again, it's not unreasonable that the subject might feel that the situation has occurred in the past, because the association is already there, independently of how the association was brought by, both times.
This might be testable.

 

[zoobyshoe]

I know what you're saying Zoob, but the way you're putting is not the way it's interpreted. It doesn't feel like a memory, like as what you described with the movie and the smell. It's not about something concrete seeming familiar, it's the impression that the situation has happened before. When i mention familiarity, I'm just suggesting that it's unconsciously triggered by some familiarity with the situation, that it's caused by this familiarity, even though you're not aware of anything concrete seeming familiar.
For example, recently before i went to bed there was a mosquito in my room, i can't sleep if there is a mosquito in the room. I had seen it but i didn't know where it was so in my attempt to move it from its hiding place i started to move things. I eventually came to my bed and shook the bed sheets, then looked at the floor in front of the bed and while doing this i had the feeling of Deja Vu, namely that this exact same thing had happened before, namely me being there doing the exact same thing for exactly the same reason. It's a familiarity with the sequence of input-thought-reaction, i.e. the situation, not with anything concrete.
I think this is what the majority of the people, who claim to have experienced Deja Vu, experience, which is possibly not the "clinical Deja Vu" that you mentioned and that is associated with a small seizure.
I think i'll leave it at that.

I can't sort out if what you're experiencing should really be called a deja vu. The explanation that satisfied you, that you had simply triggered a similar train of thought, just wouldn't work to explain the intensity of the superfamiliarity.

For clarity's sake and precision the term should only be used in conjunction with the very extreme and unmistakable experience caused by a simple partial. Neurology got dibs on it long ago. It shouldn't be used to refer to authentic memories a person can't quite place, or to situations where the dynamics of a previous situation are authentically repeated. If people are thinking of these two latter things it is no wonder they would object to the notion it's a seizure.

 

[-Job-]

I think the question can be reduced to whether it is possible to build two scenarios such that a subject, made to experience both scenarios in succession (not necessarily immediate succession), can be made to feel Deja Vu.

 

[zoobyshoe]

Can the deja vu experience vary in intensity or how long it lasts? I think there were a couple of times I had deja vu and it was just a vague feeling of familiarity lasting for a split second. I have also had a longer deja vu feeling that I've had during a conversation with someone. I know it lasted longer because I was analyzing the experience while I was talking, and I was telling the person I was having deja vu and felt I had had that conversation with her before.

All mine were all superintense and unmistakable until after a couple years I learned a trick to stop them from escalating to full intensity. Now I can say I've had some "mild" ones, referring to one's I have defused.

The length of mine is always about the same: two or three seconds of very strong familiarity that then attenuates to normal over the next few seconds. I've always assumed most people's were about the same duration and have never thought to ask people about this.

The ones I've read about that last for any appreciable length of time lead to spreading of the seizure activity to include all kinds of other symptoms. Some people have deja vu's that become compounded by extreme feelings of fear, dread, or embarrassment, for example. In others they lead to a chaotic collage of memories with strong but hard to describe emotions attached to them. In others it leads into a complex (as opposed to simple) partial seizure where there is a gross defect of consciousness.

So, I can't really say if there are people out there having mild deja vu's that are seizures because if there are they've never been given any clinical attention. The people I've talked to who clearly understand what I mean when I raise the subject all descibe experiences as intense as mine. They become visibly exited relating their story: it's clearly a remarkable, unforgettable thing for them. These are just normal people who've had one once, twice, or a few times, not people diagnosed with seizure disorders.

 

[Math Is Hard]

I think the question can be reduced to whether it is possible to build two scenarios such that a subject, made to experience both scenarios in succession (not necessarily immediate succession), can be made to feel Deja Vu.

This got me thinking how hard it would be to try to reproduce deja vu or a deja vu-like experience in a lab with means other than direct brain stimulation. It seems that this actually has been attempted, though:

In the final box are "double perception" theories of déjà vu, which descend from Allin's 1896 suggestion that a brief interruption in our normal process of perception might make something appear falsely familiar. In 1989, in one of the first laboratory studies that tried to induce something like déjà vu, the cognitive psychologists Larry L. Jacoby and Kevin Whitehouse, of Washington University in St. Louis, showed their subjects a long list of words on a screen. The subjects then returned a day or a week later and were shown another long list of words, half of which had also been on the first list. They were asked to identify which words they had seen during the first round.

The experimenters found that if they flashed a word at extremely quick, subliminal speeds (20 milliseconds) shortly before its "official" appearance on the screen during the second round, their subjects were very likely to incorrectly say that it had appeared on the first list. Those results lent at least indirect support to the notion that if we attend to something half-consciously and then give it our full attention, it can appear falsely familiar.

http://chronicle.com/free/v50/i46/46a01201.htm
I thought this entire article was a good read. It discusses alternative theories of deja vu and historical perspectives on the phenomenon.

There's a great quote from Nathaniel Hawthorne describing it as "that odd state of mind wherein we fitfully and teasingly remember some previous scene or incident, of which the one now passing appears to be but the echo and reduplication."