Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stroke: When the system fails for the second time

24.03.2020

It is now widely known that the brain is much more malleable than once thought. Even after stroke or brain injury the brain often succeeds finding a new balance between the failed regions and the functions they serve. Commonly, neighbouring regions are activated as well as homologues on the other side of the brain side. During language processing, the homologues of the left-dominant language areas are usually less active and are kept in check by the dominant half - until the emergency case occurs.

Until now, it was unclear whether these mechanisms also apply in the event of a second attack. Does the brain retain its capacity to adapt? This is important as up to 15 percent of those affected will have a second stroke. In addition, there was disagreement about whether an activated right brain is generally good for healing.


The second lesion, in which large parts of the left hemisphere are not working anymore (A, dark grey), increased the contribution of the right brain. The individual impairment predicted the activation on the right side (A, yellow). The stronger the fibre connection between the sister areas (B, red) on the right side, the less the patient was affected by the interruption on the left.

Credit: MPI CBS

Some studies suggest that involvement of the right hemisphere helps recovery, at least in the short term. Others had shown, however, that a loss of language areas in the left half can literally inhibit the right half. In that case the contribution of the right hemisphere has nothing to do with language and can cause confusion.

The brain gets out of step. Further, studies had also found that the patients are better off if the overactive half is restrained by inhibitory magnetic stimulation. The activity is more and more shifting back to the left hemisphere. It wins the upper hand again.

Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig, Germany, have now found that the brain areas on the right side also become more active when there is a second injury in the left language areas.

"In the recovered brain, the right side's contribution was still little after the first impairment. After the second event, in which large parts of the left hemisphere are not working anymore, its role becomes much more important", explains Gesa Hartwigsen, research group leader at the MPI CBS and first author of the article, which has been published in the high-ranking, open access journal elife. "The second lesion increased the contribution of the right brain", Hartwigsen said.

The scientists examined these relationships using 12 patients in whom the regions for processing properties of sound in the left hemisphere were injured. The incident had happened to them at least six months prior. Their brain had the opportunity to regenerate and adapt to the new situation.

The researchers simulated the second disruption using so-called transcranial magnetic stimulation, which can be used to briefly halt certain areas of the brain through electrical stimuli. It can be used to simulate how the brain would react if certain areas actually fail due to a stroke or other events - and how this affects the ability to recognize sounds, for example. To do this, Hartwigsen and her team used a simple decision task. T

he participants heard the word "cat" and had to decide whether it consisted of one or two syllables. The individual impairment predicted the activation on the right side.The researchers also found that the stronger the fibre connection between the sister areas on the right side, the less the patient was affected by the interruption on the left.

"These results show that after large-scale disturbances, in which large parts of the left hemisphere no longer function as they should, the right hemisphere probably plays a beneficial role. Often, there is a lot of tissue in the left half of the brain that only works to a limited extent and needs support from the right side.

"Other studies show that recovery is helped when the activated right side later down regulates itself and thus contributes to normalization on the left side", said Hartwigsen. On the other hand, if the right half remains permanently up-regulated, healing is delayed.

Findings on how the damaged brain adapts to repeated injury could help to improve the therapy of stroke patients in the long term. "This may make it possible, at some point, to assess whether it would be more helpful to regulate specific areas up or down," says Hartwigsen, confidently.

Media Contact

Verena Mueller
verenamueller@cbs.mpg.de
49-341-994-02672

 @mpi_cbs

http://www.cbs.mpg.de/en 

Verena Mueller | EurekAlert!
Further information:
http://www.cbs.mpg.de/stroke-when-the-system-fails-for-the-second-time
http://dx.doi.org/10.7554/eLife.54277

More articles from Health and Medicine:

nachricht CAR macrophages go beyond T cells to fight solid tumors
24.03.2020 | University of Pennsylvania School of Medicine

nachricht New UCI-led study reveals how skin cells prepare to heal wounds
20.03.2020 | University of California - Irvine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Stem Cells and Nerves Interact in Tissue Regeneration and Cancer Progression

Researchers at the University of Zurich show that different stem cell populations are innervated in distinct ways. Innervation may therefore be crucial for proper tissue regeneration. They also demonstrate that cancer stem cells likewise establish contacts with nerves. Targeting tumour innervation could thus lead to new cancer therapies.

Stem cells can generate a variety of specific tissues and are increasingly used for clinical applications such as the replacement of bone or cartilage....

Im Focus: Artificial solid fog material creates pleasant laser light

An international research team led by Kiel University develops an extremely porous material made of "white graphene" for new laser light applications

With a porosity of 99.99 %, it consists practically only of air, making it one of the lightest materials in the world: Aerobornitride is the name of the...

Im Focus: Cross-technology communication in the Internet of Things significantly simplified

Researchers at Graz University of Technology have developed a framework by which wireless devices with different radio technologies will be able to communicate directly with each other.

Whether networked vehicles that warn of traffic jams in real time, household appliances that can be operated remotely, "wearables" that monitor physical...

Im Focus: Peppered with gold

Research team presents novel transmitter for terahertz waves

Terahertz waves are becoming ever more important in science and technology. They enable us to unravel the properties of future materials, test the quality of...

Im Focus: Shaking off the correlated-electron traffic jam

An international team of researchers from Switzerland, Germany, the USA and Great Britain has uncovered an anomalous metallic behavior in an otherwise insulating ceramic material. The team used ultrashort light pulses with a wide range of colors to watch what happens when the insulating quasi two-dimensional material La2CuO4 (LCO) becomes a three-dimensional metal through laser irradiation. Surprisingly, the researchers found that specific vibrations of the crystal lattice are involved in this metallization process. A careful computational investigation revealed that the same vibrations that show up in this ultrafast movie can destabilize the insulating behavior all by themselves.

The condensed-matter physics world was shaken up when high-temperature superconductivity was reported in a copper oxide material in 1986 by Alex Müller and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Most significant international Learning Analytics conference will take place – fully online

23.03.2020 | Event News

MOC2020: Fraunhofer IOF organises international micro-optics conference in Jena

03.03.2020 | Event News

70th Lindau Meeting: 660 young scientists from around 100 countries experience first “Lindau Moment" today

02.03.2020 | Event News

 
Latest News

CAR macrophages go beyond T cells to fight solid tumors

24.03.2020 | Health and Medicine

A key development in the drive for energy-efficient electronics

24.03.2020 | Materials Sciences

Stroke: When the system fails for the second time

24.03.2020 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>