Bright hues to trace the brain’s wiring

A brighter multicolor labeling technique allows scientists to trace the wiring of brain cells faster and over longer distances.
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Image credit: Sakaguchi et al. (CC BY 4.0)

The brain is made up of millions of cells called neurons, and it is important to learn how these neurons are wired together to better understand how the brain works. To make it easier to tell individual neurons apart in samples from brains, some scientists have developed a process called Brainbow that labels individual neurons with different fluorescent colors. Scientists have also created techniques called “tissue clearing” to make a brain transparent in the laboratory. These techniques make the brain see-through enough to allow scientists to study the wiring of the brain in three dimensions.

These multicolor labeling and tissue clearing techniques are very helpful for studying the brain. But they have an important limitation; the fluorescent colors are not bright enough to allow scientists to trace the long extensions called axons and dendrites that wire neurons together. As a result, tracing axons and dendrites was difficult and required cutting the brain into hundreds of thin slices. It could take several months for scientists to trace the path of a single neuron. Brighter fluorescent labeling colors would allow scientists to use high-powered microscopes to trace the entire length of a neuron in a whole brain much more quickly and easily.

Now, Sakaguchi et al. have developed a bright multicolor labeling method for neurons called Tetbow. Tetbow produces more vivid colors allowing scientists to trace the wiring of neurons over long distances in the mouse brain. Sakaguchi et al. combined Tetbow with tissue clearing techniques to dissect and trace many neurons in a whole mouse brain within a few days.

Neuroscientists can now use Tetbow to speed up the study of how neurons are wired in the brain. Researchers working in other fields could also use Tetbow to help track the behavior of different cells. Tetbow allows everyone to see the beautiful wiring of the brain in three dimensions.