Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Myelin linked to speedy recovery of human visual system after tumor removal

11.12.2014

Understanding recovery process could have implications for many different injuries of the central nervous system

An interdisciplinary team of neuroscientists and neurosurgeons from the University of Rochester has used a new imaging technique to show how the human brain heals itself in just a few weeks following surgical removal of a brain tumor.


This is a human visual pathway, including the optic chiasm, tracts and radiations, revealed by MRI. This subject has a large pituitary tumor, in red, causing compression. These tumors caused by demyelination of the vision pathways and vision loss, but surgery to remove the tumor leads to remarkably rapid remyelination and vision recovery.

Credit: David A. Paul/University of Rochester School of Medicine

In a study featured on the cover of the current issue of the journal Science Translational Medicine, the team found that recovery of vision in patients with pituitary tumors is predicted by the integrity of myelin--the insulation that wraps around connections between neurons--in the optic nerves.

"Before the study, we weren't able to tell patients how much, if at all, they would recover their vision after surgery," explained David Paul, an M.D. candidate in the Department of Neurobiology and Anatomy, and first author of the study.

When pituitary tumors grow large, they can compress the optic chiasm, the intersection of the nerves that connect visual input from the eyes to the brain. Nerve compression can lead to vision loss, which usually improves after these tumors are surgically removed through the nose.

Paul and his colleagues used a technique called diffusion tensor imaging (DTI) to show how changes in a particular bundle of nerve fibers relate to vision changes in these patients.

"DTI measures how water spreads in tissue," explained Bradford Mahon, assistant professor in the Department Brain and Cognitive Sciences and the Department of Neurosurgery, and senior author of the study. "The myelin insulation normally prevents water from spreading within the nerves, which would cause the nerves to malfunction."

Paul describes myelin damage by analogy to an insulated copper cable. In the human brain, DTI can measure the "leakiness of the insulation," or how well myelin constrains the flow of water in brain tissue.

One DTI-based measurement, called radial diffusivity, can be used as an indicator of myelin insulation; an increase in this measure means there is less insulation to restrict the movement of water within a nerve. In their study, the researchers found that inadequate insulation resulted in poorer visual ability in patients.

Paul said this particular patient population is unique because unlike other diseases such as stroke, trauma or multiple sclerosis, these patients have a problem that can be treated by surgery and the effect of the tumor on the brain is the same every time. Every pituitary tumor that grows large enough will compress the optic chiasm in more or less the same place, and removal of the tumor is often followed by a recovery of visual abilities.

"These patients grant us a unique opportunity to understand human brain repair because the surgery is minimally invasive and patients recover very quickly after surgery," said Edward Vates, director of the Pituitary Program in the Department of Neurosurgery at the University of Rochester Medical Center, and co-author of the study.

The measurements established in the study provide a new way to measure the structural integrity of nerve fibers, and may ultimately be applicable across the full range of brain diseases and injuries.

"There's a lot of variability in how people recover from brain injuries," said Mahon. "Anything we can learn about patients who go on to make a good recovery may help us to promote recovery from brain injury of any cause." he adds that the visual system is the best understood circuitry in the human brain, and his lab has developed very precise ways of studying vision before and after surgery.

"If we can develop our prognostic methods in the context of the early visual pathway, then we can apply the same types of models to more complex systems in the brain, like language recovery after a stroke," said Mahon.

"This kind of research will create novel treatments to fix broken nervous systems," said Bradford Berk, director of the new Rochester Neurorestorative Institute. "Harnessing new technologies to help us understand how the brain repairs itself and restores function, and how we can accelerate that process will be one of the keys to restoring neurological function in a wide range of conditions, such as multiple sclerosis, stroke, and traumatic brain injury."

Additional researchers on the study include Elon Gaffin-Cahn, Eric B. Hintz, Giscard J. Adeclat, and Zoë R. Williams from the University of Rochester/University of Rochester School of Medicine, and Tong Zhu from the University of Michigan Medical Center.

The National Institute of Neurological Disorders and Stroke and the National Eye Institute supported the research.

About the University of Rochester

The University of Rochester is one of the nation's leading private universities. Located in Rochester, N.Y., the University gives students exceptional opportunities for interdisciplinary study and close collaboration with faculty through its unique cluster-based curriculum. Its College, School of Arts and Sciences, and Hajim School of Engineering and Applied Sciences are complemented by its Eastman School of Music, Simon Business School, Warner School of Education, Laboratory for Laser Energetics, School of Medicine and Dentistry, School of Nursing, Eastman Institute for Oral Health, and the Memorial Art Gallery.

Monique Patenaude | EurekAlert!

Further reports about: Medicine Myelin STROKE human brain multiple sclerosis nerves tumors visual system

More articles from Interdisciplinary Research:

nachricht Fighting myocardial infarction with nanoparticle tandems
04.12.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Virtual Reality for Bacteria
01.12.2017 | Institute of Science and Technology Austria

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Thanks for the memory: NIST takes a deep look at memristors

22.01.2018 | Materials Sciences

Radioactivity from oil and gas wastewater persists in Pennsylvania stream sediments

22.01.2018 | Earth Sciences

Saarland University bioinformaticians compute gene sequences inherited from each parent

22.01.2018 | Life Sciences

VideoLinks Wissenschaft & Forschung
Overview of more VideoLinks >>>