A new brain imaging technique called CLARITY allows neural structures to be reconstructed in three dimensions better than ever before. It does so by turning the brain “transparent”.
Truly understanding the inner workings of the brain means studying not only how individual neurons function, but also how they are wired together. Even with techniques like the beautiful “brainbow”, untangling spaghetti-like long-range connections has proven difficult.
Stanford University neuroscientists have taken a step in that direction with their new CLARITY method. Neurons and other cells are normally labeled by sticking fluorescent tags on various proteins and other molecules that a researcher wants to study. That way we can literally see where and how they function. But looking into a three-dimensional brain is like peering into murky water: the fatty cell membranes and neuron sheaths just get in the way.
The Stanford researchers immobilized these mouse brains in a gel, then washed away all the murky muck. This left all the connections and proteins in their right place, free to be labeled in a clear block of brain Jell-O.
Aeroelasticflutter occurs when fluid mechanical forces and structural forces get coupled together, one feeding the other. Usually, we think of it as a destructive mechanism, but, for hummingbirds, it’s part of courtship. When a male hummingbird looks to attract a mate, he’ll climb and dive, flaring his tail feathers one or more times. As he does so, air flow over the feathers causes them to vibrate and produce noise. Researchers studied such tail feathers in a wind tunnel, finding a variety of vibrational behaviors, including a tendency for constructive interference—in other words two feathers vibrating in proximity is much louder than either individually. For more, check out the original Science article or the write-up at phys.org. (Video credit: C. Clark et al.)