The brainbow technique is a complex process that involves crossing two specifically engineered transgenic species in order to create offspring with brains whose neurons each randomly express different amounts of red, blue and green fluorescent proteins, which makes it possible to mark each individual neuron with a distinctive colour. First developed in 2007 and refined in the years since, the process has made possible great advances in connectomics, the study of neural connections in the brain.
The image above, created by Assistant Professor Timothy Mosca of Thomas Jefferson University in Pennsylvania, shows a cross-section of a fruit fly brain. It stems from recent research on synaptic junctions that discovered the importance of a molecule known as LRP4 in the creation of excitatory synapses that pass a signal from one neuron to the next.
The research is published in eLife.