For the first time, researchers at Humboldt Universität zu Berlin, Bernstein Center Berlin and NeuroCure Cluster of Excellence explain how the cellular architecture of spatial memory is related to its role in orientation. In the journal Neuron, they present a new technique with which they could examine the activity and interconnection of individual neurons in freely moving animals. This method allowed them to identify the circuits with which rats capture and learn the spatial structure of their environment.
The specific wiring of two distinct cell types is the basis of our spatial memory. Henrik Gerold Vogel/ pixelio.de
Yet, it is hardly understood, which cells in our brain communicate when with each other. So far, scientists had to choose: they either investigated structure and connectivity by staining the cells or they measured their activity. To capture both simultaneously was meant to be almost impossible, particularly in freely-moving animals.
Now, Prof. Michael Brecht, head of the Bernstein Center Berlin, and his colleague Dr. Andrea Burgalossi were able to solve these problems with a new method. In collaboration with micro-mechanics of the Technische Universität Berlin, they developed a novel stabilization mechanism for the recording electrode. This allowed them to label cells in the spatial memory system of the rat (the medial entorhinal cortex) and at the same time to record their activity in freely-moving animals exploring their environment. Anatomical analyses provided important information about the interconnections of the recorded cells. With this new method the scientists could visualize for the first time the neuronal circuits involved in spatial memory formation.
In the rat’s spatial memory system, two major cell types contribute to orientation and spatial memory formation. When rats explore an environment, a subset of cells are active at the intercept points of a virtual grid spanning the entire surface of the environment. These cells, known as “grid cells”, are believed to form a map-like representation of the environment which enables the animal to “measure” distances and to estimate its position in space. The other cell type is active only when the animal faces a certain direction. These cells seem to act like a compass for the animal.
How grid and head-direction cells cooperate for orientation and spatial learning was previously unknown. Michael Brecht and Andrea Burgalossi now noted that these two functional cell types are organized in well-defined anatomical patches, and they are strictly separated from each other. By visualizing the connections between the two cell types, the researchers could also reconstruct how they cooperate for the emergence of spatial memory.
Interestingly, they discovered very selective interconnections between the two systems of cells, which could enable the animal to integrate the spatial map information with the heading-direction information. These so-called “microcircuits” might therefore constitute the basic neural units for generating a global sense of spatial orientation. Alzheimer's disease has its origin in the medial entorhinal cortex. Patients often suffer, besides other things, from disorientation. Knowledge about the organization and the interconnections between cells in this region of the brain could therefore also contribute to a fundamental understanding of Alzheimer's disease.
The Bernstein Center Berlin is part of the Bernstein Network Computational Neuroscience (NNCN) in Germany. The NNCN was established by the German Federal Ministry of Education and Research with the aim of structurally interconnecting and developing German capacities in the new scientific discipline of computational neuroscience. It was named in honor of the German physiologist Julius Bernstein (1835–1917).Original publication:
Johannes Faber | idw
What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
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...
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...
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,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering