Featured Research

from universities, journals, and other organizations

Are You Slow In Coordinating Your Thoughts?

Date:
March 15, 2004
Source:
Max Planck Society
Summary:
Many complex systems are composed of a large number of similar units that are connected in a complicated manner. An important example is provided by neural networks where nerve cells in the brain communicate by exchanging pulses via synaptic connections.

Max Planck researcher model brain structures as neural networks. Their newest findings show that the complex switching-structure of these networks result in a speed limit for the coordination of network activity.
Credit: Image : Max-Planck-Institut für Strömungsforschung

Many complex systems are composed of a large number of similar units that are connected in a complicated manner. An important example is provided by neural networks where nerve cells in the brain communicate by exchanging pulses via synaptic connections. Unlike atoms in a crystal which are arranged on a regular, e.g cubic lattice, nerve cells in the brain grow synaptic connections in a highly specific but irregular fashion. In such systems, a particular question is how rapid coordination, e.g. synchronization, between units of a complex network can be achieved. Three theoretical neuro-physicists from the Max Planck Institut for Flow Research in Goettingen have now shed new light on this question for networks of pulse-coupled oscillators, simple models of neural networks in the brain (Physical Review Letters 92: 074101, 2004).

To analyze the impact of network structure on its function the scientists use the theory of random matrices. Initiated by the work of Wigner on correlations of energy levels in atomic nuclei, random matrix theory has been extensively investigated since the 1950s. Its range of application has been continuously growing since then and today includes the study of various phenomena as different as quantum mechanical aspects of chaos and price fluctuations on financial markets. Timme, Wolf, and Geisel have now demonstrated that the theory of random matrices can also be applied to the dynamic evolution of complex networks. This new approach allows the explorationof the impact of a network's topology on its dynamics, systematically and analytically. From the theory of random matrices the researchers derived mathematical expressions which precisely determined how fast neurons can coordinate their activity, i.e. how fast neural networks can synchronize. Using these random matrix theory expressions, the dependence on properties of single neurons as well as of the network topology can be accurately predicted.

As might be expected, they found that the faster the neurons synchronize the stronger the synaptic connections between the units are. Intriguingly, however, the new study revealed that there exists a speed limit to network synchronization: Even for arbitrary strong interactions synchronization cannot be achieved faster than an upper limit. This speed limit is set by the complicated connectivity of the network and is absent if every unit is coupled to every other. The limit originates from the fact that even if only a single unit is brought out of complete synchrony this information must be spread to all units in the network before synchronization is achieved again.

If this analysis captures key mechanisms of coordinating activity in neural networks of the brain, this would mean that the speed of neural information processing, i.e. thinking and reacting, can be severely limited by network connectivity. For instance, the analysis revealed that in random networks, the speed of synchronization only slowly increases with the average number of connections per neuron. This would imply that brain areas, within which rapid information exchange is essential, have to be highly connected.


Story Source:

The above story is based on materials provided by Max Planck Society. Note: Materials may be edited for content and length.


Cite This Page:

Max Planck Society. "Are You Slow In Coordinating Your Thoughts?." ScienceDaily. ScienceDaily, 15 March 2004. <www.sciencedaily.com/releases/2004/03/040315072213.htm>.
Max Planck Society. (2004, March 15). Are You Slow In Coordinating Your Thoughts?. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2004/03/040315072213.htm
Max Planck Society. "Are You Slow In Coordinating Your Thoughts?." ScienceDaily. www.sciencedaily.com/releases/2004/03/040315072213.htm (accessed July 29, 2014).

Share This




More Matter & Energy News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) — A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Stranded Whale Watching Boat Returns to Boston

Stranded Whale Watching Boat Returns to Boston

Reuters - US Online Video (July 29, 2014) — Passengers stuck overnight on a whale watching boat return safely to Boston. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Baluchistan Mining Eyes an Uncertain Future

Baluchistan Mining Eyes an Uncertain Future

AFP (July 29, 2014) — Coal mining is one of the major industries in Baluchistan but a lack of infrastructure and frequent accidents mean that the area has yet to hit its potential. Duration: 01:58 Video provided by AFP
Powered by NewsLook.com
Easier Nuclear Construction Promises Fall Short

Easier Nuclear Construction Promises Fall Short

AP (July 29, 2014) — The U.S. nuclear industry started building its first new plants using prefabricated Lego-like blocks meant to save time and prevent the cost overruns that crippled the sector decades ago. So far, it's not working. (July 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins