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Well the Franks study probably destroyed any chance for natural sleep conditions. Nedergaard is scathing: https://www.thetransmitter.org/glymphatic-system/new-method-... > The new paper used many of the techniques incorrectly, says Nedergaard, who says she plans to elaborate on her critiques in her submission to Nature Neuroscience. Injecting straight into the brain, for example, requires more control animals than Franks and his colleagues used, to check for glial scarring and to verify that the amount of dye being injected actually reaches the tissue, she says. The cannula should have been clamped for 30 minutes after fluid injection to ensure there was no backflow, she adds, and the animals in the sleep groups are a model of sleep recovery following five hours of sleep deprivation, not natural sleep—a difference she calls “misleading.” > “They are unaware of so many basic flaws in the experimental setup that they have,” she says. > More broadly, measurements taken within the brain cannot demonstrate brain clearance, Nedergaard says. “The idea is, if you have a garbage can and you move it from your kitchen to your garage, you don’t get clean.” > There are no glymphatic pathways, Nedergaard says, that carry fluid from the injection site deep in the brain to the frontal cortex where the optical measurements occurred. White-matter tracts likely separate the two regions, she adds. “Why would waste go that way?” |