GrrlScientist is an evolutionary biologist, ornithologist, aviculturist, birder and freelance science and nature writer. A native of the Pacific Northwest, she relocated from Seattle to NYC with her parrots after earning a BS in Microbiology (emphasis in Virology) and PhD in Zoology (Ornithology) from the University of Washington. In NYC, she was the Chapman Postdoctoral Fellow at the American Museum of Natural History for two years, pursuing part of her "dream" research project by reconstructing a molecular phylogeny of the parrots of the South Pacific islands. GrrlScientist has written a blog about science since 4 August 2004 (the early years are archived 
Where in the brain does déjà vu originate? Why it happens more frequently with increasing age and with brain-disease patients? Basically, the brain generates memories near its center, in a looped wishbone of tissue called the hippocampus. But a new study suggests only a small chunk of it, called the dentate gyrus, is responsible for "episodic" memories that allows us to tell similar places and situations apart. The dentate gyrus is a region within the brain that notes a situation's pattern -- its visual, audial, olfactory, temporal and other cues for the body's future reference. So what happens when the dentate gyrus's abilities are blocked or nonfunctional?
To answer these questions, MIT neuroscientist Susumu Tonegawa and his team bred mice without a fully functional dentate gyrus. They found that the mice struggled to tell the difference between two similar but different situations.
"These animals normally have a distinct ability to distinguish between situations," Tonegawa said, which is similar to people. "But without the dentate gyrus they were very mixed up."
Basically, déjà vu is a memory problem. The term, "déjà vu" is French for "already seen" and describes the experience of feeling that one has witnessed or experienced a new situation previously. It occurs when the brain struggles to distinguish between two extremely similar situations. As people age, Tonegawa said, déjà -vu-like confusion happens more often -- and it also happens in people suffering from brain diseases like Alzheimer's.
"It's not surprising," he said, "when you consider the fact that there's a loss of or damage to cells in the dentate gyrus."
Tonegawa is a Japanese scientist who won the Nobel Prize for Physiology or Medicine in 1987 for his discovery of the genetic principle for generation of antibody diversity.
So this leads me to speculate; are republicans merely confused mice? Are their dentate gyri non-operational? If so, is this the first time that a political party has caused irreparable brain damage?
Comments
I have a feeling I have read this post before. Or perhaps not....
Posted by: coturnix | June 10, 2007 10:02 PM
I get the feeling of deja vu in my job; explaining the same thing to the same blank faces. After a while it is difficult to know which set of managers you are talking to :o)
I don't think that this is due to my brain degenerating (though how would I tell?) rather that situations can be so similar that it makes you think that you've been there before.
The article doesn't match my understanding of deja vu. It isn't really a case of struggling to understand that two situations are different events, rather that a new situation is so similar to one previously experienced that you think "done this/been here before"; not so much confusing more a short term suprise.
Posted by: Chris' Wills | June 11, 2007 1:11 AM