Our eyes once developed thousands of nerve cells (neurons) ready to be bombarded with light and colour for the very first time. The grey-coloured retinal ganglion cell pictured on the left (from a developing mouse eye) takes visual signals from the eye to the brain. Coloured dots highlight where connections (synapses) have formed with neurons near the retina’s surface – visual signals flow in from ‘excitatory’ neurons (red), and are ‘fine-tuned’ by ‘inhibitory’ neurons (connected at the green spots) before being sent brain-wards. Excitatory and inhibitory neurons arrange in specific patterns early in development (pictured on the right, in a computer reconstruction) – a bit like machinery along a production line, ready to shape and balance the huge amount of information from the eye’s first glimpse of the world.
Written by John Ankers
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences 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.