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
‘Farming’ bacteria to boost growth in the oceans
24.10.2016 | Max-Planck-Institut für marine Mikrobiologie
Calcium Induces Chronic Lung Infections
24.10.2016 | Universität Basel
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy