Post by Brad-LaSpirits on Jun 11, 2007 11:23:48 GMT -5
The brain cranks out 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—information that allows us to tell similar places and
situations apart.
The finding helps explain where déjà vu originates in the brain, and
why it happens more frequently with increasing age and with
brain-disease patients, said MIT neuroscientist Susumu Tonegawa. The
study is
detailed today in the online version of the journal Science.
Like a computer logging its programs' activities, the dentate gyrus
notes a situation's pattern—it's visual, audio, smell, time and
other cues for the body's future reference. So what happens when its
abilities are jammed?
When Tonegawa and his team bred mice without a fully-functional
dentate
gyrus, the rodents struggled to tell the difference between two
similar
but different situations.
"These animals normally have a distinct ability to distinguish
between situations," Tonegawa said, like humans. "But without the
dentate
gyrus they were very mixed up."
Déjà vu is a memory problem, Tonegawa explained, occurring when our
brains struggle to tell the difference 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."
As an aging neuroscientist, Tonegawa admitted it's a typical
phenomenon with him. "I do a lot of traveling so I show up in brand
new
airports, and my brain tells me it's been here before," he said. "But
the rest of my brain knows better."
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—information that allows us to tell similar places and
situations apart.
The finding helps explain where déjà vu originates in the brain, and
why it happens more frequently with increasing age and with
brain-disease patients, said MIT neuroscientist Susumu Tonegawa. The
study is
detailed today in the online version of the journal Science.
Like a computer logging its programs' activities, the dentate gyrus
notes a situation's pattern—it's visual, audio, smell, time and
other cues for the body's future reference. So what happens when its
abilities are jammed?
When Tonegawa and his team bred mice without a fully-functional
dentate
gyrus, the rodents struggled to tell the difference between two
similar
but different situations.
"These animals normally have a distinct ability to distinguish
between situations," Tonegawa said, like humans. "But without the
dentate
gyrus they were very mixed up."
Déjà vu is a memory problem, Tonegawa explained, occurring when our
brains struggle to tell the difference 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."
As an aging neuroscientist, Tonegawa admitted it's a typical
phenomenon with him. "I do a lot of traveling so I show up in brand
new
airports, and my brain tells me it's been here before," he said. "But
the rest of my brain knows better."
