I ve seen this before ? scientist trying to explore this phenomena. .

I ve seen this before ? scientist trying explore this phenomena. . 

The odd feeling that you get when you sense that you have already done something when you know that you are doing it for the first time is actually a scientific phenomenon called Deja vu .

It is a french word which literally means "already seen ".For example: you are visiting a country for the fist time and you go to see a famous spot and suddenly you feel that you have been there before, even when you know that you are visiting the spot for the first time.This phenomenon of deja vu has puzzled many psychoanalysts and neurologists all over the world.Many different theories have been proposed by different scholars .Some relate it to past life experiences while others associate it with fantasy or wish fullfilment .

However a more widely accepted theory relates this phenomenon with human memory and its working .This theory basically states that events and episodes which we experience are stored in our memory as individual elements or fragments of that event. Déjà vu may occur when specific aspects of a current situation resemble certain aspects of previously occurring situations; and if there is a lot of overlap between the elements of the new and old sitution ,we get a strong feeling of familiarity.Recognition memory is the type of memory that allows us to realize that what we are currently experiencing has already been experienced before, such as when we recognize a friend on the street or hear a familiar song on the radio

 The brain fluctuates between two different types of recognition memory: recollection and familiarity. Recollection-based recognition occurs when we can pinpoint an instance when a current situation has previously occurred.

For example, seeing a familiar man at a store and realizing that we’ve seen him before on the bus. On the other hand, familiarity-based recognition occurs when our current situation feels familiar, but we don’t remember when it has happened before. For example, we see that familiar man in the store, but we just can’t remember where we know him from. Déjà vu, (Listeni/?de??ɑ? ?vu?/; French pronunciation: [de.?a.vy]) from French, literally "already seen," is the phenomenon of having the strong sensation that an event or experience currently being experienced, has already been experienced in the past, whether it has actually happened or not.[1][2][3][4].Scientific approaches reject the explanation of déjà vu as "precognition" or "prophecy", but rather explain it as an anomaly of memory, which creates a distinct impression that an experience is "being recalled".[5][6] This explanation is supported by the fact that the sense of "recollection" at the time is strong in most cases, but that the circumstances of the "previous" experience (when, where, and how the earlier experience occurred) are uncertain or believed to be impossible. Two types of déjà vu are suggested to exist the pathological type of déjà vu usually associated with epilepsy and the non-pathological which is a characteristic of healthy people and psychological phenomenon.[7][8][9][10]

A 2004 survey concluded that approximately two-thirds of the population have had déjà vu experiences.[11] Other studies confirm that déjà vu is a common experience in healthy individuals, with between 31% and 96% of individuals reporting it. Déjà vu experiences that are unusually prolonged or frequent, or in association with other symptoms such as hallucinations, may be an indicator of neurological or psychiatric illness.[12]

Today, many researchers have theorized the cause of the déjà vu phenomenon. Most people know that déjà vu is the experience of familiarity with any conversation, place or event that we haven’t seen before or an event that has repeated again. The hypothesis of researchers report that déjà vu can come from three main sources:

1. Memory systems

The Medial Temporal Lobes are a region of the brain involved in storing long-term memory for events and facts. Research has proposed that the familiarity depends on “rhinal cortex” function. Recognition is linked to the “hippocampus” and because rhinal function is so complex, recollection may accidentally be directed to the hippocampus. This could cause a déjá vu experience.

2. An error in working of nervous system

In fact, many reports are proposed that déjà vu come from the irregular working of nervous system. This irregular experience was linked to process in the “medial temporal lobe” including the sensory recognition, conversation and also memory association. During the sharing of information between the nerve cells, if “mis-firing” occurs, they send a confusing message to the brain and the feeling of déjà vu can happen.

3. Mismatches and short circuits

The research proposed that déjà vu is reaction of the brain’s memory systems to a familiar experience. The information will pass short-term memory instead long-term memory. This can tell us déjà vu is happen by a mismatch between the sensory inputs and remember the new output. Finally, these hypothesis and theory are explained to us to know how and why déjà vu happens. There are many theories from other research to create ideas and explain the origin of déjà vu. However, to explain the exactly mechanisms of déjà vu, much more research, a new ideas of causing déjà vu and the believable information sources are needed.

As time passes, subjects may exhibit a strong recollection of having the "unsettling" experience of déjà vu itself, but little or no recollection of the specifics of the event(s) or circumstance(s) which were the subject of the déjà vu experience itself (the events that were being "remembered"). This may result from an "overlap" between the neurological systems responsible for short-term memory and those responsible for long-term memory, resulting in (memories of) recent events erroneously being perceived as being in the more distant past. One theory is the events are stored into memory before the conscious part of the brain even receives the information and processes it.[13] However, this explanation has been criticized that the brain would not be able to store information without a sensory input first. Another theory suggests the brain may process sensory input (perhaps all sensory input) as a "memory-in-progress", and that therefore during the event itself one believes it to be a past memory.Research has associated déjà vu experiences with good memory function.[27]

The similarity between a déjà-vu-eliciting stimulus and an existing, but different, memory trace may lead to the sensation.[14][28] Thus, encountering something which evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to experimentally reproduce the sensation, Banister and Zangwill (1941)[29][30] used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the 10 participants reporting what the authors termed "paramnesias".

Memory-based explanations may lead to the development of a number of non-invasive experimental methods by which a long sought-after analogue of déjà vu can be reliably produced that would allow it to be tested under well-controlled experimental conditions. Cleary[28] suggests that déjà vu may be a form of familiarity-based recognition (recognition that is based on a feeling of familiarity with a situation) and that laboratory methods of probing familiarity-based recognition hold promise for probing déjà vu in laboratory settings.

A recent study that used virtual reality technology to study reported déjà vu experiences supported this idea. This virtual reality investigation suggested that similarity between a new scene's spatial layout and the layout of a previously experienced scene in memory (but which fails to be recalled) may contribute to the déjà vu experience.[31][31] When the previously experienced scene fails to come to mind in response to viewing the new scene, that previously experienced scene in memory can still exert an effect—that effect may be a feeling of familiarity with the new scene that is subjectively experienced as a feeling of déjà vu, or of having been there before despite knowing otherwise.

Another possible explanation for the phenomenon of déjà vu is the occurrence of "cryptomnesia", which is where information learned is forgotten but nevertheless stored in the brain, and similar occurrences invoke the contained knowledge, leading to a feeling of familiarity because of the situation, event or emotional/vocal content, known as "déjà vu". Some experts suggest that memory is a process of reconstruction, rather than a recall of fixed, established events. This reconstruction comes from stored components, involving elaborations, distortions and omissions. Each successive recall of an event is merely a recall of the last reconstruction. The proposed sense of recognition (déjà vu) involves achieving a good ‘match’ between the present experience and our stored data. This reconstruction however, may now differ so much from the original event that we ‘know’ we have never experienced it before, even though it seems similar.[32]

Robert Efron of Boston's Veterans Hospital in 1963 proposed that déjà vu is caused by dual neurological processing caused by delayed signals in the brain. Efron found that the brain’s sorting of incoming signals is done in the temporal lobe of the brain's left hemisphere. However, signals enter the temporal lobe twice before processing, once from each hemisphere of the brain, normally with a slight delay of milliseconds between them. Efron proposed that if the two signals were occasionally not synchronized properly then they would be processed as two separate experiences, with the second seeming to be a re-living of the first.[33][34]

Dream-based explanation

One theory of déjà vu attributes the feeling of having previously seen or experienced something to having dreamt about a similar situation or place, and forgetting about it until one seems to be mysteriously reminded of the situation or the place while awake.[35]Research has associated déjà vu experiences with good memory function.[27]The similarity between a déjà-vu-eliciting stimulus and an existing, but different, memory trace may lead to the sensation.[14][28] Thus, encountering something which evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to experimentally reproduce the sensation, Banister and Zangwill (1941)[29][30] used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the 10 participants reporting what the authors termed "paramnesias".

Memory-based explanations may lead to the development of a number of non-invasive experimental methods by which a long sought-after analogue of déjà vu can be reliably produced that would allow it to be tested under well-controlled experimental conditions. Cleary[28] suggests that déjà vu may be a form of familiarity-based recognition (recognition that is based on a feeling of familiarity with a situation) and that laboratory methods of probing familiarity-based recognition hold promise for probing déjà vu in laboratory settings.

A recent study that used virtual reality technology to study reported déjà vu experiences supported this idea. This virtual reality investigation suggested that similarity between a new scene's spatial layout and the layout of a previously experienced scene in memory (but which fails to be recalled) may contribute to the déjà vu experience.[31][31] When the previously experienced scene fails to come to mind in response to viewing the new scene, that previously experienced scene in memory can still exert an effect—that effect may be a feeling of familiarity with the new scene that is subjectively experienced as a feeling of déjà vu, or of having been there before despite knowing otherwise.

Another possible explanation for the phenomenon of déjà vu is the occurrence of "cryptomnesia", which is where information learned is forgotten but nevertheless stored in the brain, and similar occurrences invoke the contained knowledge, leading to a feeling of familiarity because of the situation, event or emotional/vocal content, known as "déjà vu". Some experts suggest that memory is a process of reconstruction, rather than a recall of fixed, established events. This reconstruction comes from stored components, involving elaborations, distortions and omissions. Each successive recall of an event is merely a recall of the last reconstruction. The proposed sense of recognition (déjà vu) involves achieving a good ‘match’ between the present experience and our stored data. This reconstruction however, may now differ so much from the original event that we ‘know’ we have never experienced it before, even though it seems similar.[32]

Robert Efron of Boston's Veterans Hospital in 1963 proposed that déjà vu is caused by dual neurological processing caused by delayed signals in the brain. Efron found that the brain’s sorting of incoming signals is done in the temporal lobe of the brain's left hemisphere. However, signals enter the temporal lobe twice before processing, once from each hemisphere of the brain, normally with a slight delay of milliseconds between them. Efron proposed that if the two signals were occasionally not synchronized properly then they would be processed as two separate experiences, with the second seeming to be a re-living of the first.[33][34]

Dream-based explanation

One theory of déjà vu attributes the feeling of having previously seen or experienced something to having dreamt about a similar situation or place, and forgetting about it until one seems to be mysteriously reminded of the situation or the place while awake.[35]Research has associated déjà vu experiences with good memory function.[27]The similarity between a déjà-vu-eliciting stimulus and an existing, but different, memory trace may lead to the sensation.[14][28] Thus, encountering something which evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to experimentally reproduce the sensation, Banister and Zangwill (1941)[29][30] used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the 10 participants reporting what the authors termed "paramnesias".

Memory-based explanations may lead to the development of a number of non-invasive experimental methods by which a long sought-after analogue of déjà vu can be reliably produced that would allow it to be tested under well-controlled experimental conditions. Cleary[28] suggests that déjà vu may be a form of familiarity-based recognition (recognition that is based on a feeling of familiarity with a situation) and that laboratory methods of probing familiarity-based recognition hold promise for probing déjà vu in laboratory settings.

A recent study that used virtual reality technology to study reported déjà vu experiences supported this idea. This virtual reality investigation suggested that similarity between a new scene's spatial layout and the layout of a previously experienced scene in memory (but which fails to be recalled) may contribute to the déjà vu experience.[31][31] When the previously experienced scene fails to come to mind in response to viewing the new scene, that previously experienced scene in memory can still exert an effect—that effect may be a feeling of familiarity with the new scene that is subjectively experienced as a feeling of déjà vu, or of having been there before despite knowing otherwise.

Another possible explanation for the phenomenon of déjà vu is the occurrence of "cryptomnesia", which is where information learned is forgotten but nevertheless stored in the brain, and similar occurrences invoke the contained knowledge, leading to a feeling of familiarity because of the situation, event or emotional/vocal content, known as "déjà vu". Some experts suggest that memory is a process of reconstruction, rather than a recall of fixed, established events. This reconstruction comes from stored components, involving elaborations, distortions and omissions. Each successive recall of an event is merely a recall of the last reconstruction. The proposed sense of recognition (déjà vu) involves achieving a good ‘match’ between the present experience and our stored data. This reconstruction however, may now differ so much from the original event that we ‘know’ we have never experienced it before, even though it seems similar.[32]

Robert Efron of Boston's Veterans Hospital in 1963 proposed that déjà vu is caused by dual neurological processing caused by delayed signals in the brain. Efron found that the brain’s sorting of incoming signals is done in the temporal lobe of the brain's left hemisphere. However, signals enter the temporal lobe twice before processing, once from each hemisphere of the brain, normally with a slight delay of milliseconds between them. Efron proposed that if the two signals were occasionally not synchronized properly then they would be processed as two separate experiences, with the second seeming to be a re-living of the first.[33][34

Jamais vu

Main article: Jamais vu

Jamais vu (from French, meaning "never seen") is a term in psychology which is used to describe any familiar situation which is not recognized by the observer.

Often described as the opposite of déjà vu, jamais vu involves a sense of eeriness and the observer's impression of seeing the situation for the first time, despite rationally knowing that he or she has been in the situation before. Jamais vu is more commonly explained as when a person momentarily does not recognize a word, person, or place that they already know. Jamais vu is sometimes associated with certain types of aphasia, amnesia, and epilepsy.

Theoretically, a jamais vu feeling in a sufferer of a delirious disorder or intoxication could result in a delirious explanation of it, such as in the Capgras delusion, in which the patient takes a known person for a false double or impostor.[39] If the impostor is himself, the clinical setting would be the same as the one described as depersonalisation, hence jamais vusof oneself or of the very "reality of reality", are termed depersonalisation (or surreality) feelings.

The feeling has been evoked through semantic satiation. Chris Moulin of the University of Leeds asked 95 volunteers to write the word "door" 30 times in 60 seconds. 68 percent of the subjects reported symptoms of jamais vu, with some beginning to doubt that "door" was a real word.[39]

The experience has also been named "vuja de" and "véjà du".[40][41]

References :

1.  Wells, John C. (2008), Longman Pronunciation Dictionary (3rd ed.), Longman, ISBN 9781405881180
2. ^ "Deja Vu | Definition of Deja Vu by Merriam-Webster". Merriam-Webster. Retrieved 2018-01-27.
3. ^ Brown, A. S. (2003). "A Review of the Deja Vu Experience". Psychological Bulletin. 129: 394–413. doi:10.1037/0033-2909.129.3.394.
4. ^ O'Connor, A. R; Moulin, C. J. A. (2010). "Recognition without identification, erroneous familiarity, and déjà vu". Current Psychiatry Reports. 12: 165–173. doi:10.1007/s11920-010-0119-5.
5. ^ Schnider, Armin. (2008). The Confabulating Mind: How the Brain Creates Reality. Oxford University Press. pp. 167–168. ISBN 978-0-19-920675-9
6. ^ Blom, Jan Dirk. (2010). A Dictionary of Hallucinations. Springer. pp. 132-134. ISBN 978-1-4419-1222-0
7. ^ Ratliff, E. (02-06-2006). "Déjà Vu, Again and Again". The New York Times
8. ^ Illman, N. A.; Butler, C. R.; Souchay, C.; Moulin, C. J. A. (2012). "Déjà Experiences in Temporal Lobe Epilepsy". Epilepsy Research and Treatment. 2012: 1–15. doi:10.1155/2012/539567.
9. ^ "The Meaning of Déjà Vu", Eli Marcovitz, M.D. (1952). Psychoanalytic Quarterly, vol. 21, pages: 481–489
10. ^ The déjà vu experience, Alan S. Brown, Psychology Press, (2008), ISBN 0-203-48544-0, Introduction, page 1
11. ^ Warren-Gash, Charlotte; Zeman, Adam (2003). "Déjà vu". Practical Neurology. 3: 106–109. doi:10.1046/j.1474-7766.2003.11136.x.
12. ^ Nathan A. Illman, Chris R. Butler, Celine Souchay, and Chris J. A. Moulin. (2012). Déjà Experiences in Temporal Lobe Epilepsy. Epilepsy Research and Treatment 1–15.
13. Jump up
14. ^ Vlasov, P. N.; Chervyakov, A. V.; Gnezditskii, V. V. (2013). "Déjà vu phenomenon-related EEG pattern: Case report". Epilepsy & Behavior Case Reports. 1: 136–141. doi:10.1016/j.ebcr.2013.08.001.
15. ^ Labate, Angelo; Cerasa, Antonio; Mumoli, Laura; Ferlazzo, Edoardo; Aguglia, Umberto; Quattrone, Aldo; Gambardella, Antonio (2015). "Neuro-anatomical differences among epileptic and non-epileptic déjà-vu". Cortex. 64: 1–7. doi:10.1016/j.cortex.2014.09.020.
16. ^ Brown, A. S. (2004). "The déjà vu illusion". Current Directions in Psychological Science. 13: 256–259. doi:10.1111/j.0963-7214.2004.00320.x.
17. ^ Wild, E (Jan 2005). "Deja vu in neurology". Journal of neurology. 252 (1): 1–7. doi:10.1007/s00415-005-0677-3. PMID 15654548.
18. a b Brown, Alan S. (2004). The Déjà Vu Experience. Psychology Press. ISBN 1-84169-075-9.
19. ^ Adachi, T.; Adachi, N.; Takekawa, Y.; Akanuma, N.; Ito, M.; Matsubara, R.; Ikeda, H.; Kimura, M.; Arai, H. (2006). "Déjà Vu Experiences in Patients with Schizophrenia". Compr Psychiatry. 47: 389–393. doi:10.1016/j.comppsych.2005.12.003.
20.  Neurology Channel
21. ^ Howstuffworks "What is déjà vu?"
22. ^ Kovacs, N.; Auer, T.; Balas, I.; Karadi, K.; Zambo, K.; Schwarcz, A.; et al. (2009). "Neuroimaging and cognitive changes during déjà vu". Epilepsy & Behavior. 14: 190–196. doi:10.1016/j.yebeh.2008.08.017.
23. ^ Akgül, S; ?ksüz-Kanbur, N; Turan, G (2013). "Persistent déjà vu associated with temporal lobe epilepsy in an adolescent". Turk J Pediatr. 55: 552–554.
24. ^ Warren-Gash, C; Zeman, A (2014). "Is there anything distinctive about epileptic déjà vu?". J Neurol Neurosurg Psychiatry. 85: 143–147. doi:10.1136/jnnp-2012-303520.
25. ^ Wells, CE; Moulin, CJ; Ethridge, P; Illman, NA; Davies, E; Zeman, A (2014). "Persistent psychogenic déjà vu: a case report". J Med Case Rep. 8: 414. doi:10.1186/1752-1947-8-414. PMC 4295571 . PMID 25482434.
26. ^ Brynie, Faith (2009). Brain Sense: The Science of the Senses and How We Process the World Around Us. Amacom. p. 195.
27. ^ Adachi, N.; Akanu, N.; Adachi, T.; Takekawa, Y.; Adachi, Y.; Ito, M.; Ikeda, H. (2008). "Déjà vu experiences are rarely associated with pathological dissociation". Journal of Nervous and Mental Disease. 196: 417–419. doi:10.1097/nmd.0b013e31816ff36d.
28. ^ Taiminen, T.; J??skel?inen, S. (2001). "Intense and recurrent déjà vu experiences related to amantadine and phenylpropanolamine in a healthy male". Journal of Clinical Neuroscience. 8 (5): 460–462. doi:10.1054/jocn.2000.0810. PMID 11535020
29. ^ Bancaud, J.; Brunet-Bourgin, F.; Chauvel, P.; Halgren, E. (1994). "Anatomical origin of déjà vu and vivid 'memories' in human temporal lobe epilepsy". Brain : a journal of neurology. 117 (1): 71–90. doi:10.1093/brain/117.1.71. PMID 8149215.
30. ^ Adachi, N.; Adachi, T.; Kimura, M.; Akanuma, N.; Takekawa, Y.; Kato, M. (2003). "Demographic and psychological features of déjà vu experiences in a nonclinical Japanese population". Journal of Nervous and Mental Disease. 191: 242–247. doi:10.1097/01.nmd.0000061149.26296.dc.
31. a b Cleary, Anne M. (2008). "Recognition memory, familiarity and déjà vu experiences". Current Directions in Psychological Science. 17 (5): 353–357. doi:10.1111/j.1467-8721.2008.00605.x.
32. ^ Banister H, Zangwill OL (1941). "Experimentally induced olfactory paramnesia". British Journal of Psychology. 32: 155–175. doi:10.1111/j.2044-8295.1941.tb01018.x
33. ^ Banister H, Zangwill OL (1941). "Experimentally induced visual paramnesias". British Journal of Psychology. 32: 30–51. doi:10.1111/j.2044-8295.1941.tb01008.x.
34. a b Cleary; Brown, AS; Sawyer, BD; Nomi, JS; Ajoku, AC; Ryals, AJ; et al. (2012). "Familiarity from the configuration of objects in 3-dimensional space and its relation to déjà vu: A virtual reality investigation". Consciousness and Cognition. 21 (2): 969–975. doi:10.1016/j.concog.2011.12.010. PMID 22322010
35. ^ Youngson, R. "Deja Vu". The Royal Society of Medicine Health Encyclopedia. Dr R.M. Youngson. Retrieved 1 October 2012
36. ^ Robert, Efron. "TEMPORAL PERCEPTION, APHASIA AND DéJà VU". Brain. 86: 403–424. doi:10.1093/brain/86.3.403
37. ^ How déjà vu works by Lee Ann Obringer - How Stuff Work
38. ^ Lohff, David C. (2004). The Dream Directory: The Comprehensive Guide to Analysis and Interpretation. Running Press. ISBN 0-7624-1962-8.
39. a b Ahuja, Anjana (2006-07-24). "Doctor, I've got this little lump on my arm . . . Relax, that tells me everything". London: Times Online. Retrieved 2010-05-01.
40. ^ "The power of "Vuja De"". 2013-07-03. Retrieved 2016-04-11. something else that you’ve done a hundred times before—and you suddenly feel as if you’re experiencing something completely new. This is vuja de,
41. ^ "Adam Grant TED Talk 2016 (HD): The surprising habits of original thinkers" (published 2016-04-03). February 2016. Retrieved 2016-04-11. Véjà du is when you look at something you've seen many times before and all of a sudden see it with fresh eyes position mm:ss 11:12
42. ^ Blom, Jan Dirk (2009). A Dictionary of Hallucinations. Springer Science & Business Media. p. 422.
43. ^ Grinnel, Renée (2008). "Déjà Entendu". PsychCentral. Retrieved 2011-04-10
44. ^ Mental Status Examination Rapid Record Form