Featured Research

from universities, journals, and other organizations

Two Brains, One Thought: Wiring Diagrams Of A Neuronal Network Based On Its Dynamics

Date:
February 12, 2007
Source:
Max Planck Society
Summary:
Although no two brains are alike, they can display a comparable pattern of neural activity when exposed to similar sensory input. Max Planck scientists have now developed a mathematical method to design networks from neural cells which exhibit a predefined pattern dynamics. The researchers hope that their method will assist them in getting closer to understanding which of the possible network configurations was privileged by evolution -- and why.

Different neuronal networks can bear the same pattern of activity -- as shown in this example of a network made of 16 neurons. Similarly, the exact neuronal structures of the circuits in a human brain can differ from person to person, yet at the same time can display a comparable dynamics and the same functions. With the help of theoretical models, Memmesheimer and Timme can now deduce the possible structures from the neuronal dynamics.
Credit: Image : Max Planck Institute for Dynamics and Self-Organization

Although no two brains are alike, they can display a comparable pattern of neural activity when exposed to similar sensory input. Scientists at the Max Planck Institute for Dynamics and Self-Organization in Gφttingen have now developed a mathematical method to design networks from neural cells which exhibit a predefined pattern dynamics. The researchers hope that their method will assist them in getting closer to understanding which of the possible network configurations was privileged by evolution -- and why (Physica D: Nonlinear Phenomena, December, 2006).

The nerve cells of the brain are inter-connected to a complex network. All brain activities are the result of the "firing" of nerve cells, when they send electrical pulses - like a Morse code - to other cells of the brain. This process depends on the exact dynamics of the neuronal activity. When the brain receives sensory input, calculates or remembers, it processes information encoded in a series of neuronal impulses in different nerve cells. Although no two people have the same brain, they can still share the same thought. Thus, only to a certain extent is the dynamics of neuronal activity dependent on the structure of neuronal networks. For networks far simpler than that of the human brain this idea also applies: different structures can display the same functionality. Raoul-Martin Memmesheimer and Marc Timme, researchers at the Max Planck Institute for Dynamics and Self-Organization and the Bernstein Center for Computational Neuroscience Gφttingen, have developed a mathematical method to describe the set of all networks that exhibit a given dynamics. With this, they provide researchers with a tool which can be used to investigate the correlation between structure and function of a neuronal network.

A common approach in scientific research is to investigate the structure of a system in order to then draw conclusions about its function. Memmesheimer and Timme now took the reverse perspective. "For some simple networks we know the activity dynamics, that is, their function, but not their exact structure", explains Memmesheimer. "Any given dynamics can normally be created by a variety of different networks. We have developed a method to mathematically pin down this diversity". This procedure resembles juggling with many unknown quantities and requires great computational power. Already in a network of 1000 neurons (where each neuron can be connected to any other) there are a million possible contacts between any two neurons and consequently an unimaginably large number of possible networks. Each combination can have either an inhibiting or an activating effect on the downstream neuron and, in addition to this, can differ in its intensity and reaction time. The entirety of all possible networks of a defined dynamics resembles a complex figure in a multidimensional space. Here, every point on the surface specifies the data required to determine a network with the desired dynamics. Memmesheimer and Timme have now worked out a mathematical description for this figure.

The researchers examined the applicability of their model on the basis of a concrete question. They calculated all possible networks that generate a given dynamics and simultaneously fulfil a further condition: the structure of the network should be as simple as possible, that is, the number of connections and the strength of the synapses should be minimal. "Applied to a real network, one could for example analyse which structural optimisation principles function in evolution", says Timme. The dynamics of a number of very simple networks that generate repetitive patterns - like the insect walking pattern - are already well-understood. Has evolutionary pressure kept the structural complexity of such networks to a minimum - or could there have been other networks with an even simpler structure, yet possessing the same dynamics? Is it possible that many more networks fulfilling the same functional and structural conditions could have evolved? There is still no definite answer to these puzzles; however, with the help of the new methods developed by Memmesheimer and Timme, we are a step closer towards understanding them.

References:

R.-M.Memmesheimer, M. Timme. Designing complex networks. Physica D: Nonlinear Phenomena, December, 2006

R.-M.Memmesheimer, M. Timme. Designing the Dynamics of Spiking Neural Networks. Physical Review Letters, November 3rd, 2006


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. "Two Brains, One Thought: Wiring Diagrams Of A Neuronal Network Based On Its Dynamics." ScienceDaily. ScienceDaily, 12 February 2007. <www.sciencedaily.com/releases/2007/02/070201144735.htm>.
Max Planck Society. (2007, February 12). Two Brains, One Thought: Wiring Diagrams Of A Neuronal Network Based On Its Dynamics. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2007/02/070201144735.htm
Max Planck Society. "Two Brains, One Thought: Wiring Diagrams Of A Neuronal Network Based On Its Dynamics." ScienceDaily. www.sciencedaily.com/releases/2007/02/070201144735.htm (accessed September 23, 2014).

Share This



More Computers & Math News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Will Living Glue Be A Thing?

Will Living Glue Be A Thing?

Newsy (Sep. 23, 2014) — Using proteins derived from mussels, engineers at MIT have made a supersticky underwater adhesive. They're now looking to make "living glue." Video provided by Newsy
Powered by NewsLook.com
Company Copies Keys From Photos

Company Copies Keys From Photos

Newsy (Sep. 22, 2014) — A new company allows customers to make copies of keys by simply uploading a couple of photos. But could it also be great for thieves? Video provided by Newsy
Powered by NewsLook.com
Cat Lovers Flock to Los Angeles

Cat Lovers Flock to Los Angeles

AFP (Sep. 22, 2014) — The best funny internet cat videos are honoured at LA's Feline Film Festival. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
Raw: SpaceX Rocket Carries 3-D Printer to Space

Raw: SpaceX Rocket Carries 3-D Printer to Space

AP (Sep. 22, 2014) — A SpaceX Rocket launched from Cape Canaveral, carrying a custom-built 3-D printer into space. NASA envisions astronauts one day using the printer to make their own spare parts. (Sept. 22) 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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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