Animals and humans find their way through the world using an internally generated navigation system. In mammals, components of this navigational system are the hippocampus and the entorhinal cortex.
A grid-like network of nerve cells in the brain (left, and top right) shows a similar hexagonal organization (right, bottom) to the mental map formed by the nerve cells in the brain. Science
These structures memorize and represent our environment in form of a cognitive map, which is a mental representation of space. The representation of space in the entorhinal cortex is particularly fascinating—here, nerve cells discharge in a grid like pattern across space when the animal is moving.
It is thought that this so-called grid cell activity works much like the grid lines on a map providing mammals with a metric for space. So far, it has been unclear how such grid patterns of activated nerve cells are anatomically formed in the brain.
Now, a research team headed by Leibniz prize winner Professor Michael Brecht from the Humboldt-Universität in Berlin, the Cluster of Excellence Neurocure, and the Bernstein Center Berlin has discovered a grid-like network of nerve cells in the entorhinal cortex. By using a protein that binds to calcium in selected nerve cells, the scientists visualized a small circuit of nerve cells. The dendrites of these neurons formed a hexagonal pattern in space that had a striking resemblance to the known grid patterns. Moreover, the neurons in this network showed the same characteristic activity rhythm as the grid cells, when the researchers measured the nerve cell activity in moving animals.
“People have known that the brain divides places into grids, much like we draw lines on a map. However, what was not known is what causes the brain to do it. What we have shown here is the existence of a circuit in the brain, which physically looks like the spatial activity pattern of the so-called grid cells. This makes us think that this circuit structure might be the underlying cause of this representation”, Brecht comments on the study that has been published in the renowned scientific journal Science this Thursday.
Hence, the discovery of the neural network might help us to understand how the brain generates grid lines on our mental maps and how we mentally measure distances. The scientists also hope to gain insight into how the brain forms spatial memories—a brain function which is disturbed or lost in many neurodegenerative diseases such as dementia. On a more fundamental level, how the brain forms spatial memories may be related to how we form memories in general: as in the memory palaces of the ancient Greeks, objects could be linked with places to serve as a mnemonic device.
The Bernstein Center Berlin is part of the National Bernstein Network Computational Neuroscience in Germany. With this funding initiative, the German Federal Ministry of Education and Research (BMBF) has supported the new discipline of Computational Neuroscience since 2004 with over 170 million Euros. The network is named after the German physiologist Julius Bernstein (1835-1917).Contact:
Weitere Informationen:http://www.activetouch.de Lab of Michael Brecht
Mareike Kardinal | idw
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
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...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy