Featured Research

from universities, journals, and other organizations

Even the smallest stroke can damage brain tissue and impair cognitive function

Date:
December 16, 2012
Source:
University of California - San Diego
Summary:
Blocking a single tiny blood vessel in the brain can harm neural tissue and even alter behavior, a new study in animals has shown. But these consequences can be mitigated by a drug already in use, suggesting treatment that could slow the progress of dementia associated with cumulative damage to miniscule blood vessels that feed brain cells.

A single arteriole, highlighted in yellow, dives from the surface of the brain at the top of the image to penetrate a column of brain tissue. Blocking just one such vessel can damage the brain and lead to a focused cognitive defect, a new study has shown.
Credit: David Kleinfeld Lab, UC San Diego

Blocking a single tiny blood vessel in the brain can harm neural tissue and even alter behavior, a new study from the University of California, San Diego has shown. But these consequences can be mitigated by a drug already in use, suggesting treatment that could slow the progress of dementia associated with cumulative damage to miniscule blood vessels that feed brain cells.

The team reports their results in the Dec. 16 advance online edition of Nature Neuroscience.

"The brain is incredibly dense with vasculature. It was surprising that blocking one small vessel could have a discernable impact on the behavior of a rat," said Andy Y. Shih, lead author of the paper who completed this work as a postdoctoral fellow in physics at UC San Diego. Shih is now an assistant professor at the Medical University of South Carolina.

Working with rats, Shih and colleagues used laser light to clot blood at precise points within small blood vessels that dive from the surface of the brain to penetrate neural tissue. When they looked at the brains up to a week later, they saw tiny holes reminiscent of the widespread damage often seen when the brains of patients with dementia are examined as a part of an autopsy.

These micro-lesions are too small to be detected with conventional MRI scans, which have a resolution of about a millimeter. Nearly two dozen of these small vessels enter the brain from a square millimeter area of the surface of the brain.

"It's controversial whether that sort of damage has consequences, although the tide of evidence has been growing as human diagnostics improve," said David Kleinfeld, professor of physics and neurobiology, who leads the research group.

To see whether such minute damage could change behavior, the scientists trained thirsty rats to leap from one platform to another in the dark to get water.

The rats readily jump if they can reach the second platform with a paw or their snout, or stretch farther to touch it with their whiskers. Many rats can be trained to rely on a single whisker if the others are clipped, but if they can't feel the far platform, they won't budge.

"The whiskers line up in rows and each one is linked to a specific spot in the brain," Shih said. "By training them to use just one whisker, we were able to distill a behavior down to a very small part of the brain."

When Shih blocked single microvessels feeding a column of brain cells that respond to signals from the remaining whisker, the rats still crossed to the far platform when the gap was small. But when it widened beyond the reach of their snouts, they quit.

The FDA-approved drug memantine, prescribed to slow one aspect of memory decline associated with Alzheimer's disease, ameliorated these effects. Rats that received the drug jumped whisker-wide gaps, and their brains showed fewer signs of damage.

"This data shows us, for the first time, that even a tiny stroke can lead to disability," said Patrick D. Lyden, a co-author of the study and chair of the department of neurology at Cedars-Sinai Medical Center in Los Angeles. "I am afraid that tiny strokes in our patients contribute -- over the long term -- to illness such as dementia and Alzheimer's disease," he said, adding that "better tools will be required to tell whether human patients suffer memory effects from the smallest strokes."

"We used powerful tools from biological physics, many developed in Kleinfeld's laboratory at UC San Diego, to link stroke to dementia on the unprecedented small scale of single vessels and cells," Shih said. "At my new position at MUSC, I plan to work on ways to improve the detection of micro-lesions in human patients with MRI. This way clinicians may be able to diagnose and treat dementia earlier."


Story Source:

The above story is based on materials provided by University of California - San Diego. The original article was written by Susan Brown. Note: Materials may be edited for content and length.


Journal Reference:

  1. Andy Y Shih, Pablo Blinder, Philbert S Tsai, Beth Friedman, Geoffrey Stanley, Patrick D Lyden & David Kleinfeld. The smallest stroke: occlusion of one penetrating vessel leads to infarction and a cognitive deficit. Nature Neuroscience, 2012; DOI: 10.1038/nn.3278

Cite This Page:

University of California - San Diego. "Even the smallest stroke can damage brain tissue and impair cognitive function." ScienceDaily. ScienceDaily, 16 December 2012. <www.sciencedaily.com/releases/2012/12/121216132503.htm>.
University of California - San Diego. (2012, December 16). Even the smallest stroke can damage brain tissue and impair cognitive function. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/12/121216132503.htm
University of California - San Diego. "Even the smallest stroke can damage brain tissue and impair cognitive function." ScienceDaily. www.sciencedaily.com/releases/2012/12/121216132503.htm (accessed July 31, 2014).

Share This




More Mind & Brain News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dieting At A Young Age Might Lead To Harmful Health Habits

Dieting At A Young Age Might Lead To Harmful Health Habits

Newsy (July 30, 2014) Researchers say women who diet at a young age are at greater risk of developing harmful health habits, including eating disorders and alcohol abuse. Video provided by Newsy
Powered by NewsLook.com
It's Not Just Facebook: OKCupid Experiments With Users Too

It's Not Just Facebook: OKCupid Experiments With Users Too

Newsy (July 29, 2014) If you've been looking for love online, there's a chance somebody has been looking at how you're looking. Video provided by Newsy
Powered by NewsLook.com
How Your Face Can Leave A Good Or Bad First Impression

How Your Face Can Leave A Good Or Bad First Impression

Newsy (July 29, 2014) Researchers have found certain facial features can make us seem more attractive or trustworthy. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins