Archive | January, 2008

Brain Systems Become Less Coordinated With Age, Even In The Absence Of Disease

Some brain systems become less coordinated with age even in the absence of Alzheimer’s disease, according to a new study from Harvard University. The results help to explain why advanced age is often accompanied by a loss of mental agility, even in an otherwise healthy individual.The study was led by Jessica Andrews-Hanna, a doctoral candidate in the Department of Psychology in the Faculty of Arts and Sciences at Harvard. “This research helps us to understand how and why our minds change as we get older, and why some individuals remain sharp into their 90s, while others’ mental abilities decline as they age,” says Andrews-Hanna. “One of the reasons for loss of mental ability may be that these systems in the brain are no longer in sync with one another.” Previous studies have focused on the specific structures and functions within the brain, and how their deterioration might lead to decreased cognitive abilities. However, this study examined the way that large-scale brain systems that support higher-level cognition correlate and communicate across the brain, and found that in older adults these systems are not in sync. In particular, widely separated systems from the front to the back of the brain were less […]

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Researchers Reverse Effects Of Sleep Deprivation

esearchers at Wake Forest University School of Medicine have shown that the effects of sleep deprivation on cognitive performance can be reversed when the naturally occurring brain peptide, orexin-A, is administered in monkeys.”These findings are significant because of their potential applicability,” said Samuel A. Deadwyler, Ph.D., professor of physiology and pharmacology at Wake Forest. “This could benefit patients suffering from narcolepsy and other serious sleep disorders. But it also has applicability to shift workers, the military and many other occupations where sleep is often limited, yet cognitive demand remains high.” Orexin-A, also known as hypocretin-1, is a naturally occurring peptide produced in the brain that regulates sleep. It’s secreted by a small number of neurons but affects many brain regions during the day and people who have normal amounts of orexin-A are able to maintain wakefulness. When people or animals are sleep-deprived, the brain attempts to produce more orexin-A, but often without enough success to achieve alertness past the normal day-night cycle. The research team, consisting of Linda Porrino, Ph.D., and Robert Hampson, Ph.D, also of Wake Forest, and Jerome Siegel, Ph.D., of the University of California at Los Angeles, studied the effects of orexin-A on monkeys that were kept […]

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Hypertension Can Cause Cognitive Impairment

High blood pressure appears to be associated with an increased risk for mild cognitive impairment, a condition that involves difficulties with thinking and learning, according to a report in the December issue of Archives of Neurology, one of the JAMA/Archives journals.”Mild cognitive impairment has attracted increasing interest during the past years, particularly as a means of identifying the early stages of Alzheimer’s disease as a target for treatment and prevention,” the authors write as background information in the article. About 9.9 of every 1,000 elderly individuals without dementia develop mild cognitive impairment yearly. Of those, 10 percent to 12 percent progress to Alzheimer’s disease each year, compared with 1 percent to 2 percent of the general population. Christiane Reitz, M.D., Ph.D., and colleagues at the Columbia University Medical Center, New York, followed 918 Medicare recipients age 65 and older (average age 76.3) without mild cognitive impairment beginning in 1992 through 1994. All participants underwent an initial interview and physical examination, along with tests of cognitive function, and then were examined again approximately every 18 months for an average of 4.7 years. Individuals with mild cognitive impairment had low cognitive scores and a memory complaint, but could still perform daily activities […]

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Different Areas Of The Brain Respond To Belief, Disbelief And Uncertainty

The human mind is a prolific generator of beliefs about the world. The capacity of our minds to believe or disbelieve linguistic propositions is a powerful force for controlling both behavior and emotion, but the basis of this process in the brain is not yet understood.Sam Harris, a UCLA graduate student in the lab of Mark Cohen, a professor of psychiatry at the UCLA Center for Cognitive Neuroscience and a study co-author, and Sameer Sheth of Massachusetts General Hospital, report that functional magnetic resonance imaging (fMRI) reveals clear differences in the areas of the brain involved in belief, disbelief and uncertainty. Their results suggest that the differences among these cognitive states may one day be distinguished reliably, in real time, by techniques of neuroimaging. This finding has implications for the detection of deception, for the control of the placebo effect during drug design and for the study of any higher cognitive phenomenon in which the differences among belief, disbelief and uncertainty might be relevant. Fourteen adult volunteers were scanned in an MRI device at UCLA’s Brain Imaging Center. While inside the scanner, subjects were presented with written statements covering a broad range of topics, including mathematics, geography, factual knowledge, word […]

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Older Patients at Greater Risk for Cognitive Problems when having Surgery

Patients over the age of 60 who have elective surgeries such as joint replacements, hysterectomies and other non-emergency, inpatient procedures, are at an increased risk for long-term cognitive problems, according to a new study led by Duke University Medical Center researchers.The study also found that elderly patients who developed these postoperative cognitive problems were more likely to die in the first year after surgery. “We have known that patients undergoing heart surgery are at risk for cognitive dysfunction — problems with memory, concentration, processing of information — but the effects of non-cardiac surgeries on brain function are not as well-understood,” said Terri Monk, M.D., an anesthesiologist at Duke and the Durham Veterans Affairs Medical Center, and lead investigator on the study. “Our study found that increasing age put patients in this population at greater risk for cognitive problems and this is significant because the elderly are the fastest growing segment of the population. We know that half of all people 65 and older will have at least one surgery in their lifetime.” The researchers published their findings in the January 1, 2008 issue of the journal Anesthesiology and the results were published early online on December 27, 2007 on the […]

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