Dreamless nights: Brain activity during nonrapid eye movement sleep

(Medical Xpress) — The link between dreaming and rapid eye movement (REM) sleep are well understood – but the fact that consciousness is reduced during nonrapid eye movement (NREM) sleep is not. Recently, scientists in the Cyclotron Research Centre at the University of Liège, in Liège, Belgium, and the Institut National de la Santé et de la Recherche Médicale at the Université Pierre et Marie Curie in Paris, and the Functional Neuroimaging Unit at the Montreal Geriatrics Institute, investigated NREM sleep with the hypothesis that this phenomenon is associated with increased modularity of the brain’s functional activity during these periods. Using functional clustering – which estimates how integration is hierarchically organized within and across the constituent parts of a system they found that while in NREM sleep, hierarchically-organized large-scale neural networks were disaggregated into smaller independent modules. The researchers concluded that this difference could reduce the ability of the brain to integrate information, thereby accounting for the decreased consciousness experienced during NREM sleep.

Studies: Memory declines faster in years closest to death

Two new studies published in the April 4 online issue of Neurology, the medical journal of the American Academy of Neurology, suggest that a person’s memory declines at a faster rate in the last two-and-a-half years of life than at any other time after memory problems first begin. The second study shows that keeping mentally fit through board games or reading may be the best way to preserve memory during late life. Both studies were conducted by researchers at Rush University Medical Center.

Therapeutic approach for patients with severe depression

Brain pacemakers have a long-term effect in patients with the most severe depression. This has now been proven by scientists from the Bonn University Medical Center. Eleven patients took part in the study over a period of two to five years. A lasting reduction in symptoms of more than 50 percent was seen in nearly half of the subjects. The results are now being presented in the current edition of the journal Neuropsychopharmacology.