Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Know who your friends are

12.10.2009
The brain is a self-assembling computer, in which different types of neurons extend their processes outward to interact with each other over the course of nervous system development, establishing tentative axon–dendrite connections that are subsequently formalized as mature synapses.

There are rules governing which types of connections should be established, although it remains unclear how neurons ‘know’ these rules. “Recognition seems to occur because neurons are always connected with [the] right partners, but the real mechanisms for this recognition remain unknown—and it is even unclear whether such ‘recognition’ really takes place,” explains Masatoshi Takeichi of the RIKEN Center for Developmental Biology in Kobe.

The cerebellum primarily receives inputs from two kinds of axonal fibers: mossy fibers, originating from pontine nuclei in the cerebral cortex, and climbing fibers, which emerge from inferior olivary nuclei in the medulla. Each of these fiber types in turn associates with a specific subset of cerebellar cells; mossy fibers form synapses with granule cells (GCs), while climbing fibers connect to Purkinje cells.

Prior data indicate that these various cells interact indiscriminately early in development but then abort inappropriate connections as the brain matures, and Takeichi and graduate student Shoko Ito recently explored this phenomenon in the context of studying how cerebellar GCs find the right partner (1).

Co-cultures of GCs with pontine tissue showed little evidence of specific interaction between cells at first, but within several days began to exhibit signs of synapse formation. Interestingly, time-lapse movies revealed that dendrites from GCs appear capable of specifically recognizing mossy fibers, forming claw-like structures that physically latch onto these axons.

GCs showed markedly different behavior when cultured with climbing fibers or hippocampal cells, forming connections that displayed some characteristics of working synapses, but without the full range of morphological changes observed in dendrites from the pontine co-cultures. “Granule cells could form synapses with the correct positioning and morphology only when they met the mossy fibers,” says Takeichi. “This finding was unexpected.”

Overall, these findings suggest that although cerebellar cells can forge tentative links with a diverse array of axons, specific recognition mechanisms are in place to ensure proper synaptic wiring. “We have convincingly demonstrated that neurons do recognize their specific partners even in vitro, where environmental cues which could assist neuronal recognition are absent,” says Takeichi. Exactly which factors facilitate this recognition remains a mystery, however, and he indicates that this will be a focus of future research from his laboratory.

The corresponding author for this highlight is based at the Laboratory for Cell Adhesion and Tissue Patterning, RIKEN Center for Developmental Biology

Saeko Okada | Research asia research news
Further information:
http://www.rikenresearch.riken.jp/eng/research/6050
http://www.researchsea.com

More articles from Life Sciences:

nachricht Nonstop Tranport of Cargo in Nanomachines
20.11.2018 | Max-Planck-Institut für molekulare Zellbiologie und Genetik

nachricht Researchers find social cultures in chimpanzees
20.11.2018 | Universität Leipzig

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | 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

 
Latest News

When AI and optoelectronics meet: Researchers take control of light properties

20.11.2018 | Physics and Astronomy

Researchers use MRI to predict Alzheimer's disease

20.11.2018 | Medical Engineering

How to melt gold at room temperature

20.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>