Thousands of nerve cells (neurons) waggling around behind our developing eyes somehow connect precisely with specific neurons in the brain. This amazing feat of wiring is challenging to untangle in humans. Thankfully, the nervous system of the fruit fly (partly pictured here) works in a similar way to our own, but is much easier to investigate. On the left, two different types of neuron in the fly’s imaginal disc (its developing eye) have been genetically-modified to glow as green and red blobs. They develop at different rates – each neuron’s age is vital information used to connect it to the correct area of the brain (blue, right). Sequoia, a protein inside each neuron, organises the neurons by age, producing neat curved layers of red and green connections. These layers will eventually 'plug in' to specific brain regions, bringing vision to the fly, and perhaps a glimpse into our own development.
Written by John Ankers
BPoD stands for Biomedical Picture of the Day. Managed by the MRC Clinical Sciences Centre the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.