Posted on 12/06/2007 8:53:34 PM PST by neverdem
Even seniors fortunate enough to avoid the horrors of Alzheimer's disease typically experience some declines in memory and other cognitive abilities. Little is known about why this happens, but a new study suggests that cognitive declines in healthy older adults may result when brain regions that normally work together become out of sync, perhaps because the connections between them break down.
A team led by Harvard neuroscientists Jessica Andrews-Hanna and Randy Buckner used functional magnetic resonance imaging (fMRI) to monitor brain activity in 38 young adults, mostly 20-somethings, and 55 older adults, age 60 or above. The researchers focused on a "default" network of brain regions that are active when the brain is just idling, not working on any particular task (ScienceNOW, 18 January). The fMRI scans revealed coordinated activity in the default network in younger subjects: For example, two particular brain regions in the network tended to be active at the same time even though one is at the front of the brain and the other is near the back. In the older subjects, however, activity in these areas was poorly coordinated. In nine older adults, the researchers also performed a positron emission tomography (PET) scan that can detect amyloid protein in the brain--a hallmark of Alzheimer's disease. The PET scans were negative, suggesting that an out-of-sync default network is a part of normal aging, not a sign of disease, Buckner says.
Additional experiments using a method called diffusion tensor imaging revealed evidence of deteriorated white matter--the cables of axons connecting one brain region to another--in older adults whose default network activity was poorly coordinated. Although the role of the default network in cognition is poorly understood, coordinated activity made a difference in how people performed on tests of memory and other mental skills. Those with the least coordinated default network activity tended to get the lowest scores, the researchers report in the 6 December issue of Neuron.
"I think it's a great contribution to the field of cognitive aging," says neuroscientist Adam Gazzaley of the University of California, San Francisco. The findings, he notes, add to previous hints that the cognitive declines that happen with age result from changes in the way brain regions interact. Deteriorating white matter may turn out to be the root problem, breaking down communication links between brain regions and impairing their ability to work in a coordinated manner, says Gazzaley.
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I don’t understand a single word of this article.
bump
All the other spark plugs start misfiring, why wouldn’t the one called the brain?
Guess we had better do a study
I just wonder why they used 20-somethings. In previous posts about brain development it’s been noted that the brain isn’t really completely fully developed until about 25. If the 20-somethings were below 25, I wonder if that really is a good model of an adult brain. Perhaps adults of around 30 might be a better benchmark to get a real picture of how a fully developed, adult brain works.
Pretty snazzy.
It’s great when you get so old you can’t do it anymore, but memory is so bad you thought you did.
I mean, something has to be different.
When you consider that the brain is most receptive to information prior to the age of six and sets up self-limiting blocks after that (a self-defense measure?) it’s amazing any of us live beyond 50. We human beings are unique for surviving on the added intelligence our brains provide while our bodies lag behind many of the simpler animal’s ability to withstand the forces of nature.
One recent article said we lack the memory ability of chimpanzees. I say we obviously have enough memory and innate talent for innovation to be typing these responses on this forum while the chimps are picking parasites off their buddies.
We are probably the only creatures aware of our own mortality and the implications of our impact on the overall time line...providing that dolphins are total hedonists and whales are captives of their subsonic tradition transference loop.
“A team led by Harvard neuroscientists Jessica Andrews-Hanna and Randy Buckner used functional magnetic resonance imaging (fMRI) to monitor brain activity in 38 young adults, mostly 20-somethings, and 55 older adults, age 60 or above.”
They used 55 older adults, age 60 or above. I think that qualifies as a fully developed brain.
Gee, you get older and things stop working the way they did when you were younger.
Where’s my grant $$?
More recently, PET imaging studies using radioligands that bind directly to β-amyloid plaques have been performed.28,29 One of these ligands, Pittsburgh Compound-B (PIB), is a thioflavin derivative and appears to be relatively selective for β-amyloid plaques at the concentrations used for imaging studies. As shown in Figure 2, the binding of PIB to brain sections is highly correlated with total Aβ levels. Test/retest variability in clinical studies is less than 10% for most brain regions.30
When I'm working, everything seems to be fine. It's orderly. But if I just hang around...It's another world....kinda like wandering. I'm only 64.
I have friends dealing with their parents. It tears their heart out.
In laymens terms, they can’t work within the compound to destroy the plaque, thus the buildup of plaque disrupting the normal flow of impulses is continuous.
Well, it’s not that the info isn’t IN the brain, it’s more of an active recall issue. It’s recorded, we just may not always know where to stop the tape.
Please really read my post before replying.
It’s not the older people that I was concerned about. I was saying if they want to compare a young adult brain to an older adult brain, they should make sure that ALL the younger people measured should be over 25, because that’s the age when the brain is fully developed and the brain’s structure is done going thru major changes.
Short term memory and long term memory are two different animals. ;)
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