![]() ![]() “We saw these large waves of fluid flow that started to wash over the brain about every 20 seconds or so, and could travel quite long distances inside the brain,” she says. Lewis has expanded on Nedergaard’s studies by persuading human volunteers to have their brains imaged while they sleep. Other researchers have suggested that the glymphatic system could provide a missing link between disrupted sleep and mood disorders such as bipolar, or psychiatric diseases including schizophrenia. However, Nedergaard believes the system could be important for the clearance of many other molecules from the tau protein that accumulates in Parkinson’s disease to lactic acid, which builds up in the brain when we are awake and has been linked to seizures, to inflammatory molecules produced by immune cells resident in the brain. Other studies have found an association between lifelong sleep disruption, elevated levels of amyloid, and Alzheimer’s risk. ![]() Nedergaard showed that significantly more beta-amyloid was removed from the brain during sleep. One such molecule is beta-amyloid, a toxic protein that accumulates inside the brains of Alzheimer’s patients, and disrupts brain cell function. “Just as if you don’t have a filter in an aquarium, the fish will die in their own dirt, all this stuff accumulates in the brain that needs to be removed,” Nedergaard says. Having such a system is important because your neurons are extremely active during the day, and produce waste that needs to go somewhere. They found a series of tiny channels surrounding the brain’s blood vessels that allow CSF to filter in, and get pushed through the brain tissue by the pulse of blood alongside – and dubbed it “the glymphatic system”, because it is similar to the body’s lymphatic network except managed by the brain’s glial (support) cells. Fortunately, scientists are homing in on ways to boost this kind of sleep, which could ultimately help to keep our brains healthier for longer.ĭoctors have long recognised the restorative properties of sleep, but it wasn’t until 2012 that Prof Maiken Nedergaard at the University of Rochester Medical Centre, in the US, and her colleagues identified a previously unknown plumbing system in the brain that springs to life during sleep, and enables the organ to clean itself. We tend to get less deep sleep as we get older, making it harder to clear out the debris. If we don’t get enough regular sleep, these toxic byproducts can accumulate, gradually increasing our risk of dementia and brain diseases. Sleep is a very active state for the brain – and it seems to be a special state for fluid flow within the brain,” says Laura Lewis, assistant professor of biomedical engineering at Boston University, in the US, who has imaged this pumping process in sleeping humans. Publishers use these marks when books are returned to them.“Sleep is not just a state where things turn off. Remainder Mark - A remainder mark is usually a small black line or dot written with a felt tip pen or Sharpie on the top, bottom, side page edges and sometimes on the UPC symbol on the back of the book.If excessively worn, they will be marked as "tray worn." Flat trays for SPI games are not graded, and have the usual problems.If excessively worn, they will be marked as "card worn." The cardboard backing of miniature packs is not graded.In most cases, boxed games and box sets do not come with dice.Due to the nature of loose counters, if a game is unplayable it may be returned for a refund of the purchase price. Boardgame counters are punched, unless noted.Major defects and/or missing components are noted separately.Example, EX+ is an item between Excellent and Near Mint condition. A "plus" sign indicates that an item is close to the next highest condition.When only one condition is listed, then the box and contents are in the same condition. Boxed items are listed as "code/code" where the first code represents the box, and the second code describes the contents. ![]()
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