home about sciencentral contact
sciencentral news
life sciences physical sciences technology full archive
April 8, 2013

Brain Size and Alzheimer’s

Post/Bookmark this story:

Search (Archive Only)

Is Alzheimer's Diabetes?

Erasing Memories

Alzheimer's and Smell

  Alzheimer's Association

Alzheimer's Disease Education and Referral Center at the NIH

Alzheimer's Foundation of America

email to a friend

Research announced today suggests that having a big brain may protect you from the memory-stealing symptoms of Alzheimer's Disease, even if you have the brain plaques associated with the disease. This ScienCentral News video explains.


Interviewees: Janis Elliot, patient
Deniz Erten-Lyons, Oregon Health and Science University
Length: 1 min 25 sec
Produced by Jessica Tanenbaum
Edited by Jessica Tanenbaum/Chris Bergendorff
Copyright © ScienCentral, Inc.
with additional footage courtesy Alzheimer's Association and AARP. Special thanks to Oregon Health and Science University.

Big Brain Benefit

If plaques and tangles in the brain cause Alzheimer's Disease, why do some people with affected brains stay sharp into their nineties? Neurologist and researcher Deniz Erten-Lyons is sizing up why certain old folks have both brain plaques and intact memories. She says these special seniors have bigger brains.

As she reported to the American Academy of Neurology, her team from Oregon Health and Science University and Portland's VA Medical Center did post-mortem autopsies on research volunteers involved in long-term aging studies. After grouping together the twelve research subjects who fit their main criteria — lots of brain plaques and clear thinking and good memory before death — the researchers tried to figure out what kept this special group mentally healthy during life.

"These twelve people — even though they were in their nineties — were able to function, live independently… do their day-to-day functions without any assistance," says Erten-Lyons. When she compared these twelve people to people who did have Alzheimer's Disease and the associated brain lesions, she found a surprise.

"The group that died with sharp minds had larger brains" compared to the Alzheimer's Disease group, she says.

Years of research have established the link between plaques, tangles, and Alzheimer's Disease. Plaques are proteins that build up around brain cells, while tangles are proteins that cluster inside of brain cells. Both cause stress to brain tissue, and lead to the destruction of brain cells. Erten-Lyons says her group is looking to see if the protected group has any differences in genes or proteins that might explain why their brains are bigger and why they don't show the characteristic dementia associated with Alzheimer's Disease.

Although the total brain volume of the special group was larger than normal, the hippocampus brain regions in particular had extra bulk. That's significant, says Erten-Lyons, because these regions are important for memory storage and memory formation. "We know that the changes in Alzheimer's Disease actually start in the hippocampi. The accumulation of these tangles usually starts in the hippocampi before they move to other parts of the brain," she says.

So, could big brain at birth protect you from dementia later on? Erten-Lyons says maybe, maybe not. "There may be two reasons why the brain volume and hippocampi volume may be larger in these individuals. One is that they were just born with bigger brains and that they actually need more plaques and tangles before they reach a threshold where they actually show symptoms," she says, adding that her group favors a different theory. Based on estimations of their subjects' maximum brain size, Erten-Lyons says that more likely, the sharp seniors are protected from brain shrinkage over their lifetime. The maximum brain size data, she explains, "may suggest that they really were not necessarily born with bigger brains, but they're more resistant to losing brain instead."

That protection from losing brain cells is where Erten-Lyons says the hope for treatments lies. "If we understand the mechanism that leads to this resistance — this brain damage resulting from plaques and tangles — that will eventually lead us to new prevention and therapeutic targets as well," she says.

The researchers hope finding the genes or behaviors that affect brain size during life will lead to new treatments for Alzheimer's Disease, and that participation in research is essential for progress. "It will be only through public participation in research activities like ours that I think we'll eventually come up with prevention and therapy strategies," she says.

Erten-Lyons collaborated on this research with Randal Woltjer, Hiroko Dodge, Randal Nixon, Remi Vorobik, James F. Calvert, Marjorie Leahy, Thomas Montine, and Jeffrey Kaye. She presented her findings at the annual meeting of the American Academy of Neurology on April 15, 2008.

The research was funded by the Department of Veterans Affairs, the National Institute on Aging, and the National Institutes of Health.

       email to a friend by Jessica Tanenbaum

Science Videos     Terms of Use     Privacy Policy     Site Map      Contact      About
ScienCentral News is a production of ScienCentral, Inc. in collaboration with The Center for Science and the Media 248 West 35th St., 17th Fl., NY, NY 10001 USA (212) 244-9577. The contents of these WWW sites © ScienCentral, 2000-2013. All rights reserved. This material is based on work supported by the National Science Foundation under Grant No. ESI-0515449 The views expressed in this website are not necessarily those of The National Science Foundation or any of our other sponsors. Image Credits National Science Foundation