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 Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie

nachricht Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>