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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.”