--Original published at Allison's Psych Blog
Is not sleeping enough a factor in contracting Alzheimer’s Disease? Researchers did a study to determine if being sleep deprived increases levels of tau, eventually leading to being diagnosed with the disease. Tau is a cytoplasmic protein in neurons that spreads in structures such as tangles in diseases like Alzheimer’s, and it is known that neural synaptic strength is higher in wakefulness, so the study was conducted to see if wakefulness had an effect on the amount of the protein produced in the brain’s interstitial fluid (ISF) in mice and in humans. First, tau levels were measured in the hippocampal ISF of wild mice. It was found that during the period of the sleep cycle where the mice spend most of their sleeping time compared to the dark period of the cycle where they spend their time awake, ISF levels increased 2-fold in the dark period. Hours after the light period of the sleep cycle, the mice were forced to stay awake, and showed an increase in tau levels produced whereas, mice kept awake during the dark period did not show an increase in tau levels. With the results showing increasing tau levels in mice, the question remained whether this was true in humans. Sleep deprivation increased levels of tau in humans by 50%. Next, human tau was injected into mice to determine the long term effects. The mice were exposed to 28 days of sleep deprivation, and it was found that the tau was not altered in the hippocampus, but it was in fact spread to a region of the brain synaptically connected to the hippocampus. While these mice were being assessed for 28 days, a control group of mice was also being kept awake under these conditions without the injection of tau to act as a control. The conclusion was made that tau in mice and humans is strongly increased by sleep deprivation, showing that changes in the sleep-wake cycle can result in rapid changes of tau production. The conclusion answers the question that there may be a possible relationship between being sleep deprived and being diagnosed with Alzheimer’s disease.
Summarizing these articles was a challenge, as there is so much information in the studies that should be said to let the reader know exactly what is going on and being studied. There were parts in both articles that had information vital to the hypothesis, but were only mentioned one time with their results, and not looked at again throughout the writing. The parts mentioned talked about how there was another protein called amyloid that also spread with sleep deprivation, but was only mentioned once or twice, and did not seem vital to the research, as tau was the essential protein being studied. I also chose to not mention the five critical questions in my summary. Reading both of the articles, I noticed that there was no mention of some of the questions at all. The population studied for the research, besides the rats, was not expressed as to how the researchers chose them. This is critical in a research study, not only to find out who was studied, but for the reader to possibly connect to the research, if those chosen have qualities the reader may have. The groups were also not defined when it came to the human subjects. It was not mentioned whether there was a control, or if different types of injections were used, whether it be tau or amyloid. Because of this, the article did not allow for causal claims and does not seem to generalized to the right audience, due to not knowing who their population was that was being tested. Overall, writing a summary of two very in depth articles is a very hard thing to do, by picking what to say out of everything, you are what the reader is relying on. Journalists have a very important job to get all of the information across as possible without making the article to long or too hard for someone to understand. Fitting it all into one small summary is definitely difficult, and makes me appreciate writers a little bit more.