Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The brain still awake, even during deep sleep

09.10.2008
Sleep in man is divided in two main phases : non-REM sleep, which occupies most of our early sleep night, and REM sleep, during which our dreams prevail.

Non-REM sleep is usually considered as a compensatory ‘resting’ state for the brain, following the intense waking brain activity. Indeed, previous brain imaging studies showed that the brain was less active during periods of non-REM sleep as compared to periods of wakefulness.

Although not rejecting this concept, researchers from the Cyclotron Research Centre of the University of Liège in Belgium and from the Department of Neurology of Liege University Hospital demonstrate that, even during its deepest stages (also called ‘slow-wave-sleep’), non-REM sleep should not be viewed as a stage of constant and continuous brain activity decrease, but is also characterized by transient and recurrent activity increases in specific brain areas.

In a study published recently in the prestigious american journal « Proceedings of the National Academy of Sciences » (PNAS), the research team led by Dr Thanh Dang-Vu and Pr Pierre Maquet shows that brain activity during these sleep stages is actually profoundly influenced by spontaneous slow rhythms (also called ‘slow oscillations’) which organize neuronal functioning during non-REM sleep.

By using functional magnetic resonance imaging (fMRI) combined with electroencephalography (EEG), researchers have evidenced that these slow oscillations are associated with brain activity increases during non-REM sleep (see image, side panels), therefore discarding the concept of brain ‘quiescence’ that prevailed for a long time in the characterization of non-REM sleep. Besides, these activity increases are located in specific brain areas, including the inferior frontal gyrus, the parahippocampal gyrus, the precuneus and the posterior cingulate cortex, as well as the brainstem and cerebellum (see image, central panels).

These results improve our understanding of non-REM sleep mechanisms. On the one hand, they demonstrate that non-REM sleep is a stage of brain activation organized by the slow oscillations. On the other hand, they allow the identification of brain areas potentially involved in the generation of these oscillations, which are a hallmark of brain functioning during non-REM sleep. Moreover, by showing the activation of areas involved in the processing of memory traces such as para-hippocampal areas, the study might point to the potential functions of sleep, in particular the increasingly well-defined role of sleep in memory consolidation. Finally, the activation of areas such as the brainstem, usually associated with arousal and waking, might reveal these oscillations of non-REM sleep as ‘micro-wake’ periods allowing the brain to fulfil crucial and active functions, even during the deepest stages of sleep.

This research was supported by the National Fund for Scientific Research (Belgium), the University of Liège and the Queen Elisabeth Medical Foundation.

Didier Moreau | alfa
Further information:
http://www.ulg.ac.be
http://www.pnas.org/content/105/39/15160

Further reports about: REM sleep brain areas non-REM sleep para-hippocampal areas

More articles from Health and Medicine:

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

nachricht The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute

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: 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,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

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

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>