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 Closing the carbon loop
08.12.2016 | University of Pittsburgh

nachricht Newly discovered bacteria-binding protein in the intestine
08.12.2016 | University of Gothenburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

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:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

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...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

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...

Im Focus: Quantum Particles Form Droplets

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...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

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,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>