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August 03, 2010
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“Super-aged” brains reveal secrets of sharp old-age memory
Nov. 17, 2008
Courtesy Northwestern University
and World Science staff
Maybe you have an 85-year-old grandfather who still whips through the newspaper crossword every morning, or a 94-year-old aunt who never forgets a name or a face. They don’t seem to suffer the ravages of memory that beset most aging people. Healthy nerve cells in the brain
contain support structures called microtubules, which guide nutrients
within the cell. A special kind of protein, tau, makes the microtubules stable. Tau is changed chemically in
elderly people, especially those with Alzheimer's disease. It begins to pair with other threads of tau and they become tangled up together. When this happens, the microtubules disintegrate, collapsing the neuron's transport system. This may result first in communication malfunctions between neurons and later in cell death.
(Image courtesy Nat'l Institute on Aging)
Researchers have wondered whether the brains of the elderly with laser-sharp memory—the called “super aged”—were somehow unusual.
So instead of the common research approach of exploring what goes wrong as brain powers decline with age,
some scientists are investigating what goes right in aging brains that stay nimble.
Now one group of researchers say they have a preliminary answer. They examined the brains of five deceased people considered super aged thanks to their high performance on memory tests when they were over 80 years old.
These brains were compared to the brains of elderly people whose brain powers were normal for their age. The investigators found the super aged brains had many fewer fiber-like tangles than the brains of those who had aged normally.
The tangles consist of a protein called tau that accumulates in brain cells and is thought to eventually kill the cells. Tangles are found in moderate numbers in the brains of elderly and increase substantially in the brains of Alzheimer’s disease patients.
It seems “that some individuals are immune to tangle formation and that the presence of these tangles seems to influence cognitive performance,” said neurologist Changiz Geula of Northwestern University’s Feinberg School of Medicine. He presented the findings Nov. 16 at the Society for Neuroscience annual meeting in Washington, D.C.
Unlike tangles, structures called plaques in the brains of the super aged weren’t found to be significantly more numerous than in normally aged brains. Plaques are aggregations of protein called amyloid that build up outside brain cells and disrupt their communication. Like tangles, plaques also are found in modest numbers in the brains of aged individuals and show a dramatic increase in number in Alzheimer’s disease.
Geula said the lower number of tangles in the super aged seems to be key in maintaining memory skills. Some of the super aged in the study performed memory tasks at the level of 50-year-olds, he noted. Future research will focus on what makes cells in super aged brains more resistant to tangle formation, he added, hopefully leading to therapies that “protect average brains from memory loss.”
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Maybe you have an 85-year-old grandfather who still whips through the newspaper crossword every morning, or a 94-year-old aunt who never forgets a name or a face. They don’t seem to suffer the ravages of memory that beset most aging people. Researchers have wondered whether the brains of the elderly with laser-sharp memory—the called “super aged”—were somehow unusual. So, instead of the typical research approach of exploring what goes wrong as brain powers decline with age, a research team investigated what goes right in aging brains that stay nimble. Now the scientists say they have a preliminary answer. They examined the brains of five deceased people considered super aged thanks to their high performance on memory tests when they were over 80 years old. These brains were compared to the brains of elderly people whose brain powers were normal for their age. The investigators found the super aged brains had many fewer fiber-like tangles than the brains of those who had aged normally. The tangles consist of a protein called tau that accumulates in brain cells and is thought to eventually kill the cells. Tangles are found in moderate numbers in the brains of elderly and increase substantially in the brains of Alzheimer’s disease patients. It seems “that some individuals are immune to tangle formation and that the presence of these tangles seems to influence cognitive performance,” said neurologist Changiz Geula of Northwestern University’s Feinberg School of Medicine. He presented the findings Nov. 16 at the Society for Neuroscience annual meeting in Washington, D.C. Unlike tangles, structures called plaques in the brains of the super aged weren’t found to be significantly more numerous than in normally aged brains. Plaques are aggregations of protein called amyloid that build up outside brain cells and disrupt their communication. Like tangles, plaques also are found in modest numbers in the brains of aged individuals and show a dramatic increase in number in Alzheimer’s disease. Geula said the lower number of tangles in the super aged seems to be key in maintaining memory skills. Some of the super aged in the study performed memory tasks at the level of 50-year-olds, he noted. Future research will focus on what makes cells in super aged brains more resistant to tangle formation, he added, hopefully leading to therapies that “protect average brains from memory loss.”