Peering into the brains of live transgenic mice (literally) with microscopes, MGH researchers, led by Bradley Hyman, were able to “watch” the formation of amyloid plaques—the clumps of protein in the brain associated with Alzheimer’s disease—and found that the plaques form more quickly than first thought—within a day, according to their paper in this week’s Nature.

Based on the timing of the plaque’s formation, the researchers surmise that these clumps then trigger other changes in the brain that may lead to the disease. Whether plaques are a cause or an effect in Alzheimer’s has long been controversial. (From Nature News)

Along the same theme, a group of researchers from Children’s Hospital have created a zebrafish that remains transparent throughout its whole life. Zebrafish are a popular model organism because they are transparent as embryos. But as they grow into adults they become opaque. In their paper this week in Cell Stem Cell, the researchers, led by Leonard Zon, describe how they were able to watch tumors grow and metastasize in the fish.