Harvard researchers are making use of “Brainbow,” a colorful new technique, to visualize the circuitry of the brain in new ways.

The technique, detailed in this week’s issue of Nature, activates fluorescent proteins in neurons. The colors then combine to produce an array of more than 100 different shades.

The new approach was discovered by a team led by Jeff W. Lichtman and Joshua R. Sanes, both professors in the Department of Molecular and Cellular Biology who teach MCB 80, “Neurobiology of Behavior,” in the spring.

“Brainbow provides a way of seeing many neurons at the same time in the same place,” said Lichtman, who coined the name for the technique.

“With previous techniques, there were only a handful of colors for visualizing cells,” he said.

The technique is an enormous improvement over previous staining procedures.

“Our hope is that this new technique will provide a lot more details for how the brain is wired,” said Jean Livet, a post-doctoral researcher who worked on the study.

Lichtman is also hopeful that the new method will give neuroscientists a more complete picture of the brain.

“Right now we can’t really tell if two wires cross or are just getting very close and veering off,” he said. “Wiring will be much easier when every wire is a different color.”

Although the Harvard team has already used the technique to study the neural circuitry in mice, the researchers hope to further improve the method.

“There are some technical limitations, so we would like to make a better Brainbow,” Lichtman said. “One way is to ensure that every nerve cell in the brain is colored, to make a more ubiquitous Brainbow.”

The Brainbow technique has other applications aside from studying of the brain.

“It can be used for many things because it can look at any interaction of any cell at any time,” Livet said.

Lichtman hopes to use the new technique to better understand how the brain develops.

“In mammals, wiring changes as we grow-up, and the connections made earlier begin to be trimmed,” he said. “We hope to understand this reorganization and get a better idea of how the brain selects which connections to maintain and which to lose.”