Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Improved memory thanks to irregular sleep-wake patterns

07.08.2015

Enhanced brain activity and irregular sleep cycles improve long-term memory in mice

If you‘ve had a good night’s sleep, you are mentally more alert and your memory works more reliably. During sleep, a part of our forebrain called the prefrontal cortex remains active. It ensures that memories and learned information are transferred to our long-term memory.

Researchers from the Max Planck Institute for Experimental Medicine in Göttingen and Ludwig Maximilian University in Munich have now decoupled the production of growth factor IGF2 from the sleep-wake rhythm and found that it improved long-term memory in mice. This could also have been due to a disturbed sleep-wake rhythm. However, older mice exhibited abnormal behaviour.

High levels of IGF2 and a permanently disrupted sleep rhythm evidently damage the brain over the long term. This finding is medically significant because IGF2 is a candidate substance for improving memory impairment in Alzheimer patients.

Much of what we learn during the day is stored temporarily in the hippocampus. Later, during the transition from the waking to the sleep phase, the memories are consolidated. During sleep, memory traces are transferred to other brain regions for permanent storage. Sleep therefore plays a key role in how memories are moved from short-term to long-term memory.

Scientists have identified several mechanisms that control memory formation and regulate sleep-wake cycles, but they still do not know how the two processes interact at the molecular level. “We wanted to find out how sleep-wake regulation affects memory consolidation,” says Ali Shahmoradi from the Max Planck Institute of Experimental Medicine.

The research group tracked down the effect of a specific molecule: insulin-like growth factor 2 (IGF2). “The polypeptide evidently accelerates the consolidation of declarative memory, which is memory that can be consciously recalled. Mice with high IGF2 levels in the cerebral cortex learn faster,” says Moritz Rossner, who led the study at the Max Planck Institute in Göttingen.

The researchers studied genetically modified mice in which the sleep-wake rhythm was disturbed and normal circadian regulation of IGF2 in the cerebral cortex was switched off. This means that growth factor IGF2 and its effects were no longer linked to the sleep-wake rhythm. Moreover, production of the polypeptide was greatly increased. The mice therefore not only had a better memory than normal mice, but were also mentally fitter. However, they often had to take a nap during the activity phase in order to regenerate.

Neuroscientists believe that IGF2 improves mental performance, and it is a candidate substance for treating Alzheimer patients. The Max Planck researchers discovered in their study, however, that IGF2 causes long-term damage to the brain. The mice not only exhibited improved long-term memory but also abnormal behaviour patterns. For example, they were more nervous and anxious. And the enhanced memory performance itself proved short-lived. It declined drastically in older mice. Rossner therefore cautions: “The use of IGF2 in the treatment of Alzheimer’s disease needs to be critically examined. Our study suggests that a persistently high concentration of the substance can harm the brain.”


Contact

Prof. Moritz Rossner
Max Planck Institute for Experimental Medicine, Göttingen
Phone: +49 551 3899781

Fax: +49 551 3899758

Email: rossner@em.mpg.de


Dr Ali Shahmoradi
Stanford University
Email: shahmoradi@stanford.edu


Original publication
Ali Shahmoradi, Konstantin Radyushkin, and Moritz J. Rossner

Enhanced memory consolidation in mice lacking the circadian modulators Sharp1 and -2 caused by elevated Igf2 signaling in the cortex

PNAS, 22 June 2015

Paul C. Baier, Magdalena M. Brzózka, Ali Shahmoradi , Lisa Reinecke, Cristina Kroos, Sven P. Wichert, Henrik Oster, Michael C. Wehr, Reshma Taneja, Johannes Hirrlinger, Moritz J. Rossner

Mice lacking the circadian modulators SHARP1 and SHARP2 display altered sleep and mixed state endophenotypes of psychiatric disorders

PLoS One, 23 October 2014

Prof. Moritz Rossner | Max Planck Institute for Experimental Medicine, Göttingen
Further information:
http://www.mpg.de/9344646/memory-sleep-patterns

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>