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 Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>