Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Thinking too complicated?

05.02.2008
Neuronal activity is far more predictable than has until now been assumed

How sensitive are neuronal networks to external interference? To what extent are neuronal network processes incudung the thinking patterns of the brain predefined? These questions have been investigated by Sven Jahnke, Raoul-Martin Memmesheimer and Marc Timme at the Bernstein Center for Computional Neuroscience and the Max Planck Institute for Dynamics and Self-Organisation. They have found out that, under certain conditions, neuronal networks are more predictable than was previously assumed (Physical Review Letters, Feb. 1st, 2008)

The brain is one of the most complex objects evolution has created - more than 100 billion neurons communicate with one another through a widely branched network. Neurons process information represented as electrical impulses. Each cell computes the signals of the presynaptic cells. When it generates an impulse itself, depends on the result of this calculation. Marc Timme and collaborators have now mathematically analyzed such a system of neuronal signal transmission and have verified their theory by means of computer simulations. As in the brain, the dynamics of neuronal signal transmission in the mathematical model does not follow a recognizable order; the way in which neuronal impulses are transmitted appears to be unforeseeable. But how unpredictable is such a system really?

Researchers call a system "chaotic" if slight differences in the initial states lead to very different outcomes after long times. The behavior of chaotic systems thus cannot be predicted in the long-term. "The beat of a butterfly's wing in the Amazon Jungle can cause a hurricane in Europe", as the mathematician and meteorologist Edward N. Lorenz visualized this effect in the 1960s. In 1996 researchers of the Hebrew University in Israel demonstrated in a theoretical study that the observed irregular neuronal activity of the brain may be explained by chaotic behavior. Thus, the network would develop a very different dynamics, even if only a single neuron transmitted a signal a fraction of a second earlier or later. In the last ten years many neuroscientists assumed that such chaotic behavior generally accounts for the observed irregularities.

... more about:
»Dynamics »Neuronal »Timme »chaotic »irregular
As Timme and colleagues have now uncovered, chaotic activity only arises under certain conditions and may not be a general rule in such networks. "A combination of various new methods has made it possible for us to consider every single impulse of a neuron in a network", Jahnke explains. The researchers could show that, under certain conditions, a neuronal network is astonishingly insensitive to small temporal shifts of neuronal impulses.

"If patterns of neuronal activity are similar enough, they do not develop an entirely different dynamics, as would be expected from a chaotic system. Quite in contrast, they conform to one another in the long-term", Memmesheimer explains. In the brain this could contribute to the highly precise emergence of temporal activity patterns, so that information in such networks can be processed and calculated to a high accuracy.

Although the network appears to be highly irregular according to statistical measures, this is not necessarily an indication of a chaotic system. Rather, it can be predictable over a longer period of time. "We still have to examine more closely the circumstances under which the brain's reaction is predicatble rather that chaotic", Timme adds. In any case, the dynamics of neuronal networks is, even though highly irregular, not always as complicated as previously thought.

Original publication:
Sven Jahnke, Raoul-Martin Memeshimer and Marc Timme (2007). Stable irregular dynamics in complex neural networks. Physical Review Letters 100, 048102. DOI: 10.113/PhysRevLett.100.048102
Contact:
Dr. Marc Timme
Head of the
Network Dynamics Group
Max Planck Institut for Dynamics and Self-Organisation
Bernstein Center for Computational Neuroscience
Bunsenstr. 10
37073 Göttingen
Germany
timme@nld.ds.mpg.de

Katrin Weigmann | idw
Further information:
http://www.nld.ds.mpg.de/~timme
http://www.bernstein-zentren.de/
http://www.bccn-goettingen.de/

Further reports about: Dynamics Neuronal Timme chaotic irregular

More articles from Life Sciences:

nachricht Good preparation is half the digestion
15.11.2018 | Max-Planck-Institut für Stoffwechselforschung

nachricht How the gut ‘talks’ to brown fat
16.11.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland

15.11.2018 | Earth Sciences

When electric fields make spins swirl

15.11.2018 | Physics and Astronomy

Discovery of a cool super-Earth

15.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>