Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Highly precise wiring in the Cerebral Cortex

21.09.2017

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in this region of the brain are sorted very precisely along the electrical cables of the nerve cells.


The dense neuronal network of the medial entorhinal cortex (neuronal cables in grey) and the surprisingly precise pattern of synapses found in this part of the brain shown in color.

Max Planck Institute for Brain Research


Nerve cell “trio” (in color) found to be very specifically connected within the dense network of the brain (shown in grey)

Max Planck Institute for Brain Research

The nerve cells establish an unexpectedly precise circuit motive, in which first so-called inhibitory nerve cells are contacted before in the next step the actual (excitatory) activation of the next nerve cell can be executed.

This motif of nerve cell “trios” can be considered a core connectivity motif in this type of cortex. Scientists speculate that such a highly precise circuit motive could be used for computing hypotheses about the next step in space.

For a couple of years, novel electron microscopes and improved data analysis methods have enabled scientists to map the neuronal networks in the brain with remarkable accuracy. This rather novel research area called “Connectomics” has its own department at the Max Planck Institute for Brain Research (Frankfurt am Main), Germany.

Scientists in this department have now used their repertoire of measuring and analysis techniques to study the part of the cerebral cortex in which so-called grid cells provide a very particular representation of the space around the individual animal or human.

These grid cells are known to be active when the animal or human is located at highly ordered grid-like locations in a room or a large space. Previously, scientists around Michael Brecht of Humboldt University of Berlin, who is a co-author of this study, had already found a special arrangement of nerve cells in this region of the brain, and had speculated at the time that within these special cell assemblies particular nerve cell circuits could exist.

In the current study, the scientists looked at these circuits in more detail and found that, contrary to prior belief, the synapses, i.e. contacts other nerve cells, are exceptionally precisely positioned. Within an extremely dense network of nerve cells (looking like a dense impenetrable forest, see attached figures), the nerve cells are in fact arranged in orderly triplets, in which a nerve cell first activates an inhibitory nerve cell.

Transfer of the signal to the next excitatory nerve cell can however be hindered by the veto of the inhibitory nerve cell. This core circuit, more or less functioning like a cortical transistor, would be able to propagate information in a very selective way, for instance only when additional information about the context and the surrounding of the animal or the human is available.

The nerve cells within this transistor apparently use the very precise positioning of contact sites along their electrically conducting nerve cell cables (so-called axons). “While many consider the cerebral cortex as a randomly assembled web of nerve cells and have already turned to simulating this random network, we now discover an extremely precise connectivity pattern. In the cerebral cortex, taking a much closer look is clearly worth it”, according to Helmstaedter.

Thanks to the novel methods in Connectomics, scientists can in fact now have a much more closer look. Already the first glance into the medial entorhinal cortex provided surprising results and further studies will follow.

Weitere Informationen:

http://www.brain.mpg.de/connectomics

Dr. Arjan Vink | Max-Planck-Institut für Hirnforschung

More articles from Health and Medicine:

nachricht Collagen nanofibrils in mammalian tissues get stronger with exercise
14.12.2018 | University of Illinois College of Engineering

nachricht New discoveries predict ability to forecast dementia from single molecule
12.12.2018 | UT Southwestern Medical Center

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Data use draining your battery? Tiny device to speed up memory while also saving power

14.12.2018 | Power and Electrical Engineering

Tangled magnetic fields power cosmic particle accelerators

14.12.2018 | Physics and Astronomy

In search of missing worlds, Hubble finds a fast evaporating exoplanet

14.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>