Research deciphers 'déjà -vu' brain mechanics
-
http://web.mit.edu/newsoffice/2007/deja-vu-0607.html
Research deciphers 'déjà -vu' brain mechanics
Deborah Halber, News Office Correspondent
June 7, 2007
Neuroscientists at the Picower Institute for Learning and Memory at MIT report in the June 7 early online edition of Science that they have identified for the first time a neuronal mechanism that helps us rapidly distinguish similar, yet distinct, places. The discovery helps explain the sensation of déjà vu.
The work could lead to treatments for memory-related disorders, as well as for the confusion and disorientation that plague elderly individuals who have trouble distinguishing between separate but similar places and experiences.
Forming memories of places and contexts in which episodes occur engages a part of the brain called the hippocampus. Study co-author Susumu Tonegawa, Picower Professor of Biology and Neuroscience, and colleagues have been exploring how each of the three hippocampal subregions--the dentate gyrus, CA1 and CA3--contribute to different aspects of learning and memory.
Tonegawa, a Howard Hughes Medical Institute investigator and a frequent world traveler, described his own occasional experience of finding the airport in a new city uncannily familiar. This occurs, he said, because of the similarity of the modules--gates, chairs, ticket counters--that comprise airports worldwide. It is only by seeking out unique cues that the specific airport can be identified, he said. "In this study, we have revealed that learning in the dentate gyrus is crucial in rapidly recognizing and amplifying the small differences that make each place unique," Tonegawa said.
In addition to Tonegawa, authors include Picower Institute research scientist Thomas J. McHugh; former MIT postdoctoral associate Matthew W. Jones; Matthew A. Wilson, Picower Scholar and Professor; and colleagues from the University of California at Los Angeles and Beth Israel Deaconess Medical Center in Boston.
Overlapping blueprints
In this study, the researchers used a genetically altered mouse to pinpoint how the dentate gyrus contributes to the kind of pattern separation involved in telling the difference between new and old spaces.
Researchers believe that a set of neurons called place cells fire to provide a sort of blueprint for any new space we encounter. The next time we see the space, those same neurons fire. Thus we know when we've been somewhere before and don't have to relearn our way around familiar turf.
But if we enter a space very similar to one we have seen before, a new but overlapping set of neurons creates the blueprint. When there is enough overlap between the two sets, we experience an eerie feeling of déjà vu--a French phrase that literally means, "already seen."
As we age, or as neurodegenerative disease such as Alzheimer's advances, it becomes difficult to form unique memories for similar yet distinct places and experiences, leading to the confusion that afflicts some elderly individuals.
Forgetting fear
In experiments with mice genetically engineered to lack a certain gene in the dentate gyrus, Tonegawa and colleagues pinpointed the signaling pathway underlying the recall of specific places.
Different sets of mice were placed in two similar chambers, one of which gave them a mild foot shock. After three days, the mice began to freeze in fear in both chambers, even the one in which they had never been harmed.
Within two weeks, the normal mice learned to associate only one chamber with the foot shocks while recognizing the second as safe. The genetically engineered mice "had a significant but transient deficit in their ability to distinguish similar contexts," McHugh said. "This study shows that plasticity--the ability to change in response to experience--in the dentate gyrus contributes to spatial learning and fine-tuning pattern separation."
This work was supported by the National Institute for Mental Health and the National Institutes of Health. -
Nice article.
-
what is deja-vu? i dont understand
-
déjà vu--a French phrase that literally means, "already seen."Originally posted by SmarTiNsaNE:what is deja-vu? i dont understand -
Have you ever had the experience where something happens, and you could have sworn that you already seen it happen?Originally posted by SmarTiNsaNE:what is deja-vu? i dont understand
Like if someone comes up to you and says, "hey want to go get ice cream?" and then you suddenly think to yourself "Wait! Didn't you just ask me that 5 mins ago?"
It's like that scene in the matrix where Neo sees the cat walking by the staircase, and moments later, he sees the same scene again.
The term "déjà vu" (IPA:/deʒa vy/) (French for "already seen", also called paramnesia from the Greek word para (παρα
for parallel and mnimi (μνήμη for memory) describes the experience of feeling that one has witnessed or experienced a new situation previously. The term was coined by a French psychic researcher, Émile Boirac (1851–1917) in his book L'Avenir des sciences psychiques (The Future of Psychic Sciences), which expanded upon an essay he wrote while an undergraduate French concentrator at the University of Chicago. The experience of déjà vu is usually accompanied by a compelling sense of familiarity, and also a sense of "eeriness", "strangeness", or "weirdness". The "previous" experience is most frequently attributed to a dream, although in some cases there is a firm sense that the experience "genuinely happened" in the past. Déjà vu has been described as "Remembering the future."
The experience of déjà vu seems to be very common; in formal studies 70% or more of the population report having experienced it at least once. References to the experience of déjà vu are also found in literature of the past, indicating it is not a new phenomenon. It has been extremely difficult to invoke the déjà vu experience in laboratory settings, therefore making it a subject of few empirical studies. Recently, researchers have found ways to recreate this sensation using hypnosis.[1] -
and supertitious people like to find supertitious reasons for the experience like without scientific process like saying that the person find a place he never went before but experience deja vu as a evidence of past lives.
this are so called the common sense reasoning error of superstition and how it arise from such common sense reasoning. -
January, I don't mean any offense here, but your gross misspelling of "superstitious" has serious implications on your post. Particularly in a not-so-clean way.Originally posted by january:and supertitious people like to find supertitious reasons for the experience like without scientific process like saying that the person find a place he never went before but experience deja vu as a evidence of past lives.
this are so called the common sense reasoning error of superstition and how it arise from such common sense reasoning.
Well, we all get deja vu sometimes. I tend to feel that, but I don't say it's God that made me feel it. It's more of like a forgotten memory or something. Like I thought of it before, then some time later, I feel it again, and I recall what I had felt then. -
I must confess that I am not a big fan of supertit. Average sized tit will do.Originally posted by january:and supertitious people like to find supertitious reasons for the experience like without scientific process like saying that the person find a place he never went before but experience deja vu as a evidence of past lives.
this are so called the common sense reasoning error of superstition and how it arise from such common sense reasoning.
-
Ha ha!Originally posted by Phaze:I must confess that I am not a big fan of supertit. Average sized tit will do. Yeah, that's what I meant by gross misspelling. -
so stutterdam is a god believer?
-
You referring to me? If so, get the name right, please. And yes, if you didn't notice from what I've been writing in other topics, I did say I am a Chrisitian, but I do welcome reason and logic.Originally posted by january:so stutterdam is a god believer?