The Brainbow

“Brainbow” is what Harvard researchers are calling a new genetic technique that makes it possible to visualize the complete neuronal circuits in “exquisite detail,” as today’s Neurophilosophy contains fully colored (indeed) images of a “Brainbow” and an explanation of how the technique was developed:

The technique, called Brainbow, works in much the same way as a television uses the three primary colours to generate all the colour hues. With multiple combinations of up to four differently coloured fluorescent proteins, a palette of approximately 100 labels has been produced.

To develop Brainbow, the researchers used the Cre/loxP site-specific recombination system, a sophisticated method which is commonly used to generate mutant (or “knockout”) mice lacking a specific gene.

The technique enables researchers to label not only large numbers of neurons, but also the connections they form, and thus may be of use in “mapping out” the unusual neurological writing of an autistic person. From the Independent Online (New Zealand):

The study, which appears in the journal Nature, was led by Harvard postdoctoral fellow Jean Livet. It draws its inspiration from the jellyfish Aequorea victoria, which has a gene that makes a glowing green fluorescent protein.

Researchers have figured out how to splice this gene into laboratory mice to make only their neurons glow. At first, they only glowed green. But others have tinkered with the gene to create hues of red, yellow and blue.

Now, Livet has figured out how to mix and match these colours to create roughly 90 bright hues that form a riotous display. He used a genetic recombination system known as Cre/lox to arrange the genes that encode the coloured proteins, lighting up only nerve cells in mice.

Improvements in techniques—the Brainbow makes it possible to make more complete and detailed neuronal diagrams—can indeed increase understanding and knowledge, by giving us tools to re-envision what is already there.