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

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 December 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 contributeover the long termto 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." --Susan Brown


Contact: David Kleinfeld
University of California - San Diego

Related biology news :

1. U-M forecasters predict second-smallest Gulf of Mexico dead zone
2. Smallest and largest fetuses at greater risk of being stillborn, research finds
3. Do the worlds smallest flies decapitate tiny ants?
4. By detecting smallest virus, researchers open possibilities for early disease detection
5. Integrated Biometrics Introduces Sherlock The Worlds Lightest, Thinnest, Smallest, Appendix F Mobile ID Fingerprint Sensors
6. Study finds soda consumption increases overall stroke risk
7. Study: In-patient, out-patient stroke rehab might benefit from yoga
8. Reorganizing brain could lead to new stroke, tinnitus treatments
9. Brain-wave-reading robot might help stroke patients
10. Double duty: Immune system regulator found to protect brain from effects of stroke
11. Stem cells can repair a damaged cornea
Post Your Comments:
Related Image:
Even the smallest stroke can damage brain tissue and impair cognitive function
(Date:4/15/2016)... , April 15, 2016 ... "Global Gait Biometrics Market 2016-2020,"  report to their ... ) , ,The global gait biometrics market ... 13.98% during the period 2016-2020. Gait ... which can be used to compute factors that ...
(Date:3/31/2016)... 31, 2016  Genomics firm Nabsys has completed a ... Barrett Bready , M.D., who returned to the company ... technical leadership team, including Chief Technology Officer, John ... Steve Nurnberg and Vice President of Software and Informatics, ... Dr. Bready served as CEO of Nabsys ...
(Date:3/22/2016)... OTTAWA, Ontario , PROVO ... 2016 Newborn Screening Ontario (NSO), which operates ... for molecular testing, and Tute Genomics and ... process management technology respectively, today announced the launch of ... new next-generation sequencing (NGS) testing panel. ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... -- Liquid Biotech USA , Inc. ... Research Agreement with The University of Pennsylvania ("PENN") ... patients.  The funding will be used to assess ... outcomes in cancer patients undergoing a variety of ... to support the design of a therapeutic, decision-making ...
(Date:6/24/2016)... on a range of subjects including policies, debt and investment ... Speaking at a lecture to the Canadian Economics ... the country,s inflation target, which is set by both the ... "In certain areas there needs to be frequent ... not sit down and address strategy together?" He ...
(Date:6/24/2016)... ... ... While the majority of commercial spectrophotometers and fluorometers use the z-dimension of 8.5 ... end machines that use the more unconventional z-dimension of 20mm. Z-dimension or ... the cuvette holder. , FireflySci has developed several Agilent flow cell product lines ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... the release of its second eBook, “Clinical Trials Patient Recruitment and Retention Tips.” ... and retention in this eBook by providing practical tips, tools, and strategies for ...
Breaking Biology Technology: