Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: smart on 29/03/2017 22:07:38

Title: What is a déjà vu?
Post by: smart on 29/03/2017 22:07:38

Sometimes I can feel that my thoughts have been scripted into a series of synchronized events, like a computer program, and I can "predict" the exact motion, similar to watching a movie. I find this phenomenon extremely weird, and it usually last a few seconds. Did you ever experienced a similar phenomenon?

Thanks.

Title: Re: What is a déjà vu?
Post by: chris on 29/03/2017 23:40:23

Haven't we had this question before?!

More seriously, this programme recorded recently contains an answer (admittedly from me, in a live phone-in format) to this question:

https://www.thenakedscientists.com/podcasts/ask-naked-scientists/what-causes-deja-vu

Chris

Title: Re: What is a déjà vu?
Post by: smart on 30/03/2017 00:54:48

Any idea why Wikipedia is listing a "flashback" and a "déjà vu" in separated pages??

Title: Re: What is a déjà vu?
Post by: smart on 30/03/2017 01:06:07

Quote

Temporally-Specific Retrograde Amnesia in Two Cases of Discrete Bilateral Hippocampal Pathology
ABSTRACT:
The  role  of  the  hippocampus  in  retrograde  amnesia  remains  controversial  and  poorly  understood.  Two  cases  are  reported  of discrete bilateral hippocampal damage, one of which was a rare case of limbic  encephalitis  secondary  to  the  human  herpes  virus  6.  Detailed memory  testing  showed  marked  anterograde  memory  impairment,  but only mild, temporally-limited retrograde amnesia that covered a period of several years in both autobiographical and factual knowledge domains. The absence of extensive retrograde amnesia in these two cases points to a time-limited  role  for  the  hippocampus  in  the  retrieval  of  retrograde memories, and suggests that entorhinal, perirhinal, parahippocampal, or neocortical  areas  of  the  temporal  lobe  may  be  more  critical  than  the
hippocampus proper for long-term retrograde memory functioning. Our findings offer general support to theories of memory consolidation that propose a gradual transfer of memory from hippocampal to neocortical dependency.

http://www2.psych.ubc.ca/~pgraf/Psy583Readings/Kapur%201999.pdf

Title: Re: What is a déjà vu?
Post by: mrsmith2211 on 30/03/2017 01:20:28

My thoughts are Deja Vu are experiences repeated.Now it might have been a dream repeated in reality Have been there but the why and how,precognition?  de javu is not a quantifiable replicable  experience that can be tested. It is not even a matter of enjoying the circumstance, and not a matter I would change things even if I could.

Title: Re: What is a déjà vu?
Post by: smart on 30/03/2017 01:53:39

Quote from: mrsmith2211 on 30/03/2017 01:20:28

My thoughts are Deja Vu are experiences repeated.Now it might have been a dream repeated in reality Have been there but the why and how,precognition?  de javu is not a quantifiable replicable  experience that can be tested. It is not even a matter of enjoying the circumstance, and not a matter I would change things even if I could.

You cannot repeat the past in real life...
However, I believe retrograde amnesia may cause episodes of deja vu, tricking your hippocampal neurons to replicate a time-dependent event.

See: https://en.wikipedia.org/wiki/Retrograde_amnesia#Infections

Title: Re: What is a déjà vu?
Post by: mrsmith2211 on 30/03/2017 23:46:35

I meant in De Ja Vu experiences, I do exactly a repitition, and when it happens I am not able to rethink say answers to questions.

Title: Re: What is a déjà vu?
Post by: Demolitiondaley on 31/03/2017 19:14:48

Quote from: tkadm30 on 30/03/2017 00:54:48

Any idea why Wikipedia is listing a "flashback" and a "déjà vu" in separated pages??

I'd say deja vu is an experience in which you have a feeling that you have been there before but can't remember exactly when or how in contrast to a flashback which I would describe as memory of an actual event brought about by external stimulus for example a smell or noise that is associated with the actual event that is being recalled.

Title: Re: What is a déjà vu?
Post by: smart on 14/04/2017 11:24:30

Quote from: Demolitiondaley on 31/03/2017 19:14:48

I'd say deja vu is an experience in which you have a feeling that you have been there before but can't remember exactly when or how in contrast to a flashback which I would describe as memory of an actual event brought about by external stimulus for example a smell or noise that is associated with the actual event that is being recalled.

Something like a dream, can be replicated consciously I suppose.

Title: Re: What is a déjà vu?
Post by: neilep on 14/04/2017 14:35:33

Tuvok from Voyager quoted my favourite definition of déjà vu

"Perhaps you are experiencing a paradoxical state dependant associative phenomenon"

Now if thats not a great chat up line then I dont know what is !

Title: Re: What is a déjà vu?
Post by: chris on 15/04/2017 09:13:49

Quote from: Demolitiondaley on 31/03/2017 19:14:48

I'd say deja vu is an experience in which you have a feeling that you have been there before but can't remember exactly when or how in contrast to a flashback which I would describe as memory of an actual event brought about by external stimulus for example a smell or noise that is associated with the actual event that is being recalled.

That's a very good distinction; almost as good as the one from @neilep above!