Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A study shows how the brain switches into memory mode


Researchers from Germany and the USA have identified an important mechanism with which memory switches from recall to memorization mode. The study may shed new light on the cellular causes of dementia. The work was directed by the University of Bonn and the German Center for Neurodegenerative Diseases (DZNE). It is being published in the renowned journal “Neuron.”

Because of its shape, the control center of memory bears the poetic name of “hippocampus” (seahorse). New sensations to be stored continually enter this region of the brain. But at the same time, the hippocampus is also the guardian of memories: It retrieves stored information from the depths of memory.

Exposed to new sensations certain nerve cells, via their appendages (green in the image), release acetylcholine into the hippocampus. The astrocytes (red) release glutamate.

(c) Photo: Milan Pabst & Oliver Braganza/University of Bonn

The hippocampus is also an important transport junction. And just like rush hour in a major city, it also needs a regulating hand to control the opposing flows of information. The researchers from Bonn, Los Angeles and Palo Alto have now identified such a memory traffic policeman. Certain cells in the brain, the hippocampal astrocytes, ensure that the new information is given priority. The mind thus switches into memorization mode; by contrast, the already saved memories must wait.

However, the astrocytes themselves only take orders: They react to the neurotransmitter acetylcholine, which is released in particular in novel situations. It has been known for several years that acetylcholine promotes the storage of new information. How this happens has only been partly understood.

“In our work, we were able to show for the first time that acetylcholine stimulates astrocytes which then are induced to release the transmitter glutamate,” explains Milan Pabst, who is a doctoral candidate at the Laboratory for Experimental Epileptology of the University of Bonn. “The released glutamate then activates inhibitory nerve cells which inhibit a pathways mediating the retrieval of memories.”

The researchers working with the neuroscientist Prof. Dr. Heinz Beck genetically modified nerve cells so that they could be activated by light and then release acetylcholine. Using this trick, they were able to clarify the mechanism using recordings in living brain tissue sections. “However, we also show that, in the brains of living mice, acetylcholine has the same effect on the activity of the neurons,” explains Pabst’s colleague, Dr. Holger Dannenberg.

Astrocytes have long since been underestimated

Another reason this result is interesting is because astrocytes themselves are not nerve cells. They belong to what are known as glial cells. Until the turn of the millennium, they were still considered to merely serve as mechanical support to the real stars of the brain, the neurons.

In recent decades, however, it has become increasingly clearer that this image is far from correct. It is known by now that astrocytes can release neurotransmitters – the messengers by which neurons communicate with each other – or even remove them from the brain.

“It was previously unknown that the astrocytes are involved in central memory processes through the mechanism which has now been discovered,” explains Prof. Beck. However, an observation made by US scientists in 2014 fits into this context: If astrocytes’ function is inhibited, this has a negative effect on the recognition of objects.

The results may also shed new light on the cellular causes of memory disorders. Thus there are indications that the controlled secretion of acetylcholine is disrupted in patients with Alzheimer’s dementia. “However, we have not investigated whether the mechanism we discovered is also impacted,” stresses Pabst.

Publication: Milan Pabst, Oliver Braganza, Holger Dannenberg, Wen Hu, Leonie Pothmann, Jurij Rosen, Istvan Mody, Karen van Loo, Karl Deisseroth, Albert Becker, Susanne Schoch, Heinz Beck: Astrocyte intermediaries of septal cholinergic modulation in the hippocampus; Neuron, DOI: 10.1016/j.neuron.2016.04.003

Media contact information:

Prof. Dr. Heinz Beck
Laboratory for Experimental Epileptology, University of Bonn
& German Center for Neurodegenerative Diseases (DZNE)
Tel. ++49-228-6885270

Milan Pabst
Laboratory for Experimental Epileptology, AG Beck & Neuronal Networks in Health & Disease, AG Mody, University of Bonn
Tel. ++49-228-6885332

Johannes Seiler | idw - Informationsdienst Wissenschaft

More articles from Health and Medicine:

nachricht Inflammation Triggers Unsustainable Immune Response to Chronic Viral Infection
24.10.2016 | Universität Basel

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

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: Light-driven atomic rotations excite magnetic waves

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...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

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...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

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...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

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...

Im Focus: New Products - Highlights of COMPAMED 2016

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...

All Focus news of the innovation-report >>>



Event News

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

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

First-time reconstruction of infectious bat influenza viruses

25.10.2016 | Life Sciences

Novel method to benchmark and improve the performance of protein measumeasurement techniques

25.10.2016 | Life Sciences

Amazon rain helps make more rain

25.10.2016 | Life Sciences

More VideoLinks >>>