Featured Research

from universities, journals, and other organizations

Brain Reprograms Itself After Stroke -- Functional MRI Reveals Brain’s Innate Plasticity And Charts A Direction For Rehabilitation

Date:
February 19, 2001
Source:
University Of Illinois At Chicago
Summary:
Functional imaging of the brain demonstrates that this highly complex organ adapts to injury by redistributing its cognitive workload across established neural networks and recruiting local cortical areas to fill in for lost functions like speech and language comprehension.

Functional imaging of the brain demonstrates that this highly complex organ adapts to injury by redistributing its cognitive workload across established neural networks and recruiting local cortical areas to fill in for lost functions like speech and language comprehension.

“Functional MRI [magnetic resonance imaging] indicates that the dogma that some areas of the brain are not important for normal function is clearly fallacious,” said Dr. Keith Thulborn, director of MR research at the University of Illinois at Chicago at the annual meeting of the American Association for the Advancement of Science in San Francisco. “Loss of any brain tissue is likely to compromise the reserve capacity of many large-scale neurocognitive networks that will ultimately be reflected in the performance of more difficult tasks or recovery from subsequent disease processes.”

Watching the brain at work with a very-high-field MRI scanner, Thulborn has mapped a two-stage recovery process in patients who lost their language skills after strokes. In one patient suffering from damage to Wernicke’s area (the region in the left cortex that controls the understanding of language), functional MRI showed that the brain initially recouped by allocating speech comprehension to an area on the opposite side of the brain. Over time, while Wernicke’s area remained damaged, an adjacent area took on this cognitive task.

The ability of the brain to maintain performance by recruiting undamaged portions of the cortex may suggest why functional recovery can occur even after large strokes, said Thulborn.

One key factor in recovery time, Thulborn suggested, is whether white matter has been damaged. White matter consists of myelinated neuronal axons that serve as cables linking the different areas of the cortex. When these are injured, vital connections needed to allocate functions elsewhere are lost.

“The involvement of white matter tracts portends slower and reduced recovery,” said Thulborn. “This may reflect reduced capacity to redistribute workload when the connectivity through white matter is disrupted.”

While functional MRI has been largely used in research to map brain functions, it is just beginning to find clinical applications. At the UIC Medical Center, Thulborn is collaborating with other physicians, psychologists and therapists to use the technology in designing and monitoring rehabilitation programs aimed at restoring lost cognitive and motor skills. In this role, Thulborn said, functional MRI can guide and refine therapies to enhance the brain’s innate plasticity.

The very-high-field MRI scanner works by picking up faint magnetic signals in the underlying tissue. As neurons become increasingly active in specific regions of the brain, blood flow surges to those regions and blood volume expands.

In the process, deoxygenated blood is replaced with oxygenated blood, the two differing in their magnetic properties. The MRI scanner is able to detect this magnetic change, although minute, because of the scanner’s high magnetic field strength: 3.0 Tesla, twice that of MRI scanners more commonly deployed in clinical settings. (A Tesla is equivalent to 10,000 gauss; the magnetic field strength of Earth is less than one gauss.) Cross-sectional images are made through the entire brain to create a three-dimensional view. The images must be run through a series of statistical programs so that they can be correctly interpreted.

To obtain images of the working brain, patients are placed on a table and moved into the center of the magnet. The images are taken while patients are engaged in a set of cognitive tasks devised to correlate functional activities with specific areas of the brain. To map the language comprehension network of the brain, for example, patients are given sentences of varying complexity to read and asked to answer true/false questions by pressing a finger switch. To map the motor and sensory areas, patients simply tap a finger.

Thulborn cautioned that these cognitive tasks must be carefully selected if they are to be of value in answering clinical questions. Moreover, they need to be “robust,” or reproducible, and appropriate to the patient’s level of education and cognitive and motor abilities. “Careful attention to matching the skills of each patient to the stimulus task is required to avoid variable performance that may alter the functional mapping,” said Thulborn.


Story Source:

The above story is based on materials provided by University Of Illinois At Chicago. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Chicago. "Brain Reprograms Itself After Stroke -- Functional MRI Reveals Brain’s Innate Plasticity And Charts A Direction For Rehabilitation." ScienceDaily. ScienceDaily, 19 February 2001. <www.sciencedaily.com/releases/2001/02/010219080616.htm>.
University Of Illinois At Chicago. (2001, February 19). Brain Reprograms Itself After Stroke -- Functional MRI Reveals Brain’s Innate Plasticity And Charts A Direction For Rehabilitation. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2001/02/010219080616.htm
University Of Illinois At Chicago. "Brain Reprograms Itself After Stroke -- Functional MRI Reveals Brain’s Innate Plasticity And Charts A Direction For Rehabilitation." ScienceDaily. www.sciencedaily.com/releases/2001/02/010219080616.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