Injury to brain 'hubs' does more damage

Date: Oct-14-2014 Hubs are locations in the brain where different networks come together

to help us think and complete mental tasks. Now, a new study offers a fresh view

of how injury affects the brain. It finds damage to brain hubs disrupts our

capacity to think and adapt to everyday challenges more severely than damage to

locations distant from hubs.

The researchers, from the University of Iowa in Iowa City, and Washington

University in St. Louis (WUSTL), MO, report their study in the Proceedings of

the National Academy of Sciences (PNAS).

They hope their findings will improve the prediction of the effects of stroke,

trauma and other types of damage to the brain and eventually lead to a better way

of weighing up the likely risks of some brain surgeries, as co-senior author

Steven Petersen, a professor in cognitive neuroscience and neurology at WUSTL,

explains:

"This isn't ready for application in the clinic yet, but as we get a better

feel for where these and other hubs are found in the brain, they may factor into

surgical decision-making. The risks of surgeries to these sites could include

significant impairment of attention, memory, language, speech and many other

cognitive functions."

He goes on to mention how some disorders like schizophrenia also disrupt a

similar range of brain functions. He suggests perhaps their findings highlight

some of the areas that may contribute to such conditions.

Study pinpoints brain hubs that play key role in several mental

functions

For their study, the researchers used a framework they constructed to locate

six hubs - specific points at network boundaries where they come together. Nobody

had identified these locations as hubs before.

Colors illustrate different networks of the brain. Researchers have discovered that injuries to a brain hub (top), where the boundaries of several networks come together, can be much more devastating than similar injuries in other parts of the brain (bottom).
Image credit: Steven E. Petersen

In their background information they explain that previous studies have

identified hubs in the human brain, but these used data from patients' brain

scans, and "there is little consensus on the localization of such hubs."

They proposed that their particular framework - which is based on network

measures - would predict and find hubs that play "influential roles in multiple

aspects of cognition," and that other approaches can only find hubs that do not

exert such broad influence.

Prof. Petersen says they thought their hubs were points where all the

different networks talked to each other, and if that were true, then "damage in

these areas could disrupt several networks, impairing multiple mental

functions."

They tested their idea by examining data from the Iowa Neurological Patient

Registry - a database of patients who had suffered strokes and other brain

injuries. Co-senior author Daniel Tranel, a professor in neuroscience at Iowa,

heads the Registry.

The Registry holds data not only on the location of any damage in the brain,

but also how the injuries have affected patients' behavior and thinking skills.

For example, it holds results of memory, speech and reasoning tests, and

assessments of patients' ability to work, deal with daily life and relate to

family and friends.

Looking through the Registry the team found 19 patients with brain injuries

to the six hubs they predicted with their framework. They compared these patients

with 11 others who had brain injuries of a similar size but located in places far

away from any of the six hubs.

Injury to a predicted hub linked to more severe cognitive impairment

They found the patients with injuries to a hub showed much more impairment to

cognitive skills and ability to cope with everyday life.

"For example," says Prof. Petersen, "18 of the 19 patients with harm to a hub

experienced 'real-world' problems, while less than half of the group with

injuries far from hubs had such difficulties."

He suggests the findings may explain why some patients experience surprisingly significant impairment following a small brain injury.

He says it would have been very difficult to find the hubs if they had only

studied patients. By doing the brain mapping first, they found the hubs fairly

quickly, then all they had to do was test the idea using the information in the

Iowa Registry.

The team is continuing to investigate other potential brain hubs and to use

the Registry to confirm them.

Funds from the National Institutes of Health (NIH), the James S. McDonnell

Foundation, and the Simons Foundation helped finance the study.

Medical News Today recently learned about a study that linked decreased brain connectivity to the chronic pain condition fibromyalgia. The

researchers found the disorder is associated with abnormal activity

in parts of the brain that process pain signals and link them to other

regions.

Written by Catharine Paddock PhD

Copyright: MNT
Not to be reproduced without permission.

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.