Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Highways of the Brain: High-Cost and High-Capacity

20.06.2012
A new study proposes a communication routing strategy for the brain that mimics the American highway system, with the bulk of the traffic leaving the local and feeder neural pathways to spend as much time as possible on the longer, higher-capacity passages through an influential network of hubs, the so-called rich club.

The study, published this week online in the Early Edition of the Proceedings of the National Academy of Sciences, involves researchers from Indiana University and the University Medical Center Utrecht in the Netherlands and advances their earlier findings that showed how select hubs in the brain not only are powerful in their own right but have numerous and strong connections between each other.

The current study characterizes the influential network within the rich club as the "backbone" for global brain communication. A costly network in terms of the energy and space consumed, said Olaf Sporns, professor in the Department of Psychological and Brain Sciences at IU Bloomington, but one with a big pay-off: providing quick and effective communication between billions and billions of brain cells.

"Until now, no one knew how central the brain's rich club really was," Sporns said. "It turns out the rich club is always right in the middle when it comes to how brain regions talk to each other. It absorbs, transforms and disseminates information. This underscores its importance for brain communication."

In earlier work, using diffusion imaging, the researchers found a group of 12 strongly interconnected bihemispheric hub regions, comprising the precuneus, superior frontal and superior parietal cortex, as well as the subcortical hippocampus, putamen and thalamus. Together, these regions form the brain's "rich club." Most of these areas are engaged in a wide range of complex behavioral and cognitive tasks, rather than more specialized processing such as vision and motor control.

For the current study, Martijn van den Heuvel, a professor at the Rudolf Magnus Institute of Neuroscience at University Medical Center Utrecht, used diffusion tensor imaging data for two sets of 40 healthy subjects to map the large-scale connectivity structure of the brain. The cortical sheet was divided into 1,170 regions, and then pathways between the regions were reconstructed and measured. As in the previous study, the rich club nodes were widely distributed and had up to 40 percent more connectivity compared to other areas.

The connections measured -- almost 700,000 in total -- were classified in one of three ways: as rich club connections if they connected nodes within the rich club; as feeder connections if they connected a non-rich club node to a rich club node; and as local connections if they connected non-rich club nodes. Rich club connections made up the majority of all long-distance neural pathways. The study also found that connections classified as rich club connections were used more heavily for communication than other feeder and local connections. A path analysis showed that when a minimally short path is traced from one area of the brain to another, it travels through the rich club network 69 percent of the time, even though the network accounts for only 10 percent of the brain.

A common pattern in communication paths spanning long distances, Sporns said, was that such paths involved sequences of steps leading across local, feeder, rich club, feeder and back to local connections. In other words, he said, many communication paths first traveled toward the rich club before reaching their destinations.

"It is as if the rich club acts as an attractor for signal traffic in the brain," Sporns said. "It soaks up information which is then integrated and sent back out to the rest of the brain."

Van den Heuvel agreed.

"It's like a big 'neuronal magnet' for communication and information integration in our brains," he said. "Seeking out the rich club may offer a strategy for neurons and brain regions to find short communication paths across the brain, and might provide insight into how our brain manages to be so highly efficient."

From an evolutionary standpoint, it was important for the brain to minimize energy consumption and wiring volume, but if these were the only factors, there would be no rich club because of the extra resources it requires, Sporns said. The rich club is expensive, at least in terms of wiring volume, and perhaps also in terms of metabolic cost. The trade-off for higher cost, Sporns said, is higher performance -- the integration of diverse signals and the ability to select short paths across the network.

"Brain neurons don't have maps; how do they find paths to get in touch? Perhaps the rich club helps with this, offering the brain's neurons and regions a way to communicate efficiently based on a routing strategy that involves the rich club."

People use related strategies to navigate social networks.

"Strangely, neurons may solve their communication problems just like the people to which they belong," Sporns said.

Co-authors of "High-cost, high-capacity backbone for global brain communication" are Rene S. Kahn, University Medical Center, Utrecht; and Joaquin Goni, Indiana University.

Van den Heuvel was supported by a Fellowship of the Rudolf Magnus Institute of Neuroscience and by the Dutch Brain foundation. Sporns and Goñi were supported by the JS McDonnell Foundation.

A copy of the study is available through Eurekalert. For additional assistance, contact Tracy James, IU Communications, at 812-855-0084 or traljame@iu.edu.

Sporns can be reached at 812-855-2772 or osporns@indiana.edu. Van den Heuvel can be reached at 31 88-75-58244 or m.p.vandenheuvel@umcutrecht.nl

Tracy James | Newswise Science News
Further information:
http://www.iu.edu

More articles from Studies and Analyses:

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>