Researchers have caught sight of Alzheimer’s-like plaques in the brains of rabbits using a conventional MRI scan, in what could be an important step towards early detection of Alzheimer’s in humans. Researchers say that an earlier, easier diagnosis of the disease would allow patients to try more drugs and other therapies that could slow the progress of dementia.
Diagnosis by a commonly available clinical MRI scan would be a vast improvement over current methods. Many tools are used to look for signs of Alzheimer’s, including a battery of cognitive and behavioral tests… and imaging studies called PET scans that require the injection of special chemicals that help light up the brain. But doctors can make a definitive diagnosis only after a patient dies by identifying the presence of brain lesions called amyloid plaques [USA Today].
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In a day of mixed results for Alzheimer’s research, researchers found that an experimental vaccine failed to prevent the disease’s crippling dementia, but also noted that a drug once used to treat hayfever “significantly” improves the symptoms of memory loss. The two separate studies were both published in the Lancet [subscription required], and offer a telling reminder that in medical research progress against a disease is rarely straightforward.
The first study treated patients who had already been diagnosed with Alzheimer’s with a vaccine that targeted the protein plaques that clump around brain cells in increasing numbers as Alzheimer’s progresses. The theory was that dementia could be slowed or reversed once the plaques were cleared [HealthDay News]. However, the vaccine had no effect on the patients’ slide into dementia, despite the fact that autopsies of patients who died during the study showed that the plaques had largely vanished.
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Researchers have made a map of the human brain that shows a dense network of connections at the top of the cerebral cortex, suggesting that electrical signals travel through this hub on their way to more specialized regions. “This is just about the coolest paper I’ve seen in a long time, and forward-looking in terms of where the science is going,” said Dr. Marcus E. Raichle, a professor of neurology and radiology… who was not involved in the research. He added, “They’ve found in the brain what looks like a hub map of the airline system for the United States” [The New York Times].
An international team of researchers used a technique called diffusion spectrum imaging to map the connections between different parts of the brain. The technique traces the path of water moving along axons, long fibers that extend from a neuron’s main body and carry electrical signals [Science News]. They found the most connections at the top of the cortex along the crack that separates the brain’s two hemispheres. According to researchers, that area is not only a relay station, it’s also the area that’s most active when the brain is in “default mode,” the activation state present when the brain is not engaged in any specific cognitive task [The Scientist].
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The “good” cholesterol that is found in olive oil and avocados has been portrayed as a good fairy lately based on its association with healthy hearts, but a new study may give people another reason to chow down on guacamole. A broad study of people in their 50s and 60s revealed that low levels of good cholesterol are linked to poor memory, which may be an early indicator of dementia and Alzheimer’s.
The results, reported in a journal [subscription required] published by the American Heart Association, showed that 60-year-olds with low levels of good cholesterol were 53 percent more likely to have memory problems. However, other researchers point out that the study did not prove causation, and said the study did not yet support larger diet trials aiming to boost levels [BBC News].
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The onset of dementia in an aging relative can be a devastating thing to watch, as memory and cognition slowly degrade. But a new study suggests one easy thing you can do to help hold back the fog: Turn on bright lights, and keep them on all day.
The study in the Journal of the American Medical Association [subscription required] suggests that this simple intervention may boost a patients’ cognition by reinforcing the body’s circadian clock, the sleep-wake cycle that can be modulated by daylight. When the circadian rhythms are disrupted (as in a case of jet-lag), the brain releases hormones and other agents that can affect cognition.
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