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.
GLUT5 fluorescent probe fingerprints cancer cells
20.04.2018 | Michigan Technological University
Scientists re-create brain neurons to study obesity and personalize treatment
20.04.2018 | Cedars-Sinai Medical Center
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy