Comparisons of the brains of young and old people have revealed that normal aging may cause cognitive decline due to deterioration of the connections among large-scale brain systems. The researchers linked the deterioration to a decrease in the integrity of the brain’s “white matter,” the tissue containing nerve cells that carry information. The researchers found that the disruption occurred even in the absence of pathology associated with Alzheimer’s disease (AD).
Randy Buckner and his colleagues reported their findings in the December 6, 2007, issue of the journal Neuron, published by Cell Press.
The researchers assessed brain function in a sample of adults ranging in age from 18 to 93 and comprising 38 young adults and 55 older adults. They did so using functional magnetic resonance imaging (fMRI), which uses harmless radio waves and magnetic fields to measure blood flow in brain regions, which in turn reflects activity.
To assess the integrity of functional connections between brain areas, the researchers used fMRI to measure spontaneous low-frequency fluctuations known to reflect the activity of such connections. The researchers concentrated on large-scale connections between frontal and posterior brain regions that are associated with high-level cognitive functions such as learning and remembering.
The researchers reported a “dramatic reduction” in functional connections when they compared the younger and older groups.
The researchers also used an MRI technique called “diffusion tensor imaging” to measure the integrity of white matter in the brains of the subjects. This technique reveals details of the structure of brain tissue. Their analysis revealed that the reduced functional connection they detected in brain areas of the older subjects was correlated with decreased white matter integrity.
When the researchers tested the subjects’ cognitive function, they found that “Those individuals exhibiting the lowest functional correlation also exhibited the poorest cognitive test scores.”
The researchers concluded that “our observations suggest that within the context of globally intact brain systems, subtle changes accumulate over time in advanced aging that disrupt the coordination of large-scale brain systems.”
They also said that, although AD is known to produce similar deterioration due to pathological deposits of amyloid protein, “Our present results, in particular the analysis of individuals without amyloid deposition, show that normal aging is associated with a form of system disruption that is distinct from that associated with AD.”
Source: Cell Press
Related stories:
Pregnancy not turning minds to mush: Study
Pregnancy and motherhood may make us all go a little gooey, but it's not turning mums' brains into mush, according to mental health researchers at The Australian National University.
Clue to genetic cause of fatal birth defect
A novel enzyme may play a major role in anencephaly, offering hope for a genetic test or even therapy for the rare fatal birth defect in which the brain fails to develop, according to a study from researchers at the University of Illinois at Chicago College of Medicine.
Circadian clock may be critical for remembering what you learn
(PhysOrg.com) -- The circadian rhythm that quietly pulses inside us all, guiding our daily cycle from sleep to wakefulness and back to sleep again, may be doing much more than just that simple metronomic task, according to Stanford researchers.
World-first device may help solve child language mystery
(PhysOrg.com) -- Researchers are one step closer to understanding why children can learn languages far more easily than adults, thanks to a world-first device that allows scientists to measure the magnetic fields generated by a child's brain.
Researchers propose minocycline as a promising drug for patients with Fragile X syndrome
A UC Riverside-led team of biomedical scientists has found that a readily available drug called minocycline, used widely to treat acne and skin infections, can be used to treat
Fragile X syndrome, the most common inherited cause of mental impairment and the most common cause of autism.
Musicians use both sides of their brains more frequently than average people
Supporting what many of us who are not musically talented have often felt, new research reveals that trained musicians really do think differently than the rest of us. Vanderbilt University psychologists have found that professionally trained musicians more effectively use a creative technique called divergent thinking, and also use both the left and the right sides of their frontal cortex more heavily than the average person.
This is your brain on politics
U.S. presidential candidates have been stumping for nearly two years with their every move being analyzed and reported ad nauseum. Logically, voters should be able to tap into lots of information when they make their decisions come November. But it turns out there's a lot more going on when we step behind the curtain to cast our ballot.
New piece in reading ability 'jigsaw'
(PhysOrg.com) -- A gene thought to be associated with dyslexia is also connected with reading ability in the general population, according to Oxford University research.