This may look like a mountain range but it’s actually a tiny part of a goldfish brain (one trillion times smaller than the Alps). A high-powered microscope shows two nerve cells (neurons) meeting face to face – a neuron called a mauthner cell (artificially-coloured yellow here) covers most of the picture, and is seen bordering another neuron (coloured pale green). Electrical messages once jumped between these neurons, across narrow gaps called synapses (located at the yellow-green coloured spots). The purple-coloured areas are glutamate receptors, which help to control the synapses, while black dots highlight channels in the synapses (called connexons) that transfer speedy signals from one neuron to the next. Mauthner cells receive warning signals from the goldfish’s sensory nerves, triggering a quick tail-flip to aid a fishy escape – a glimpse at their architecture has much to teach us about the 100 trillion synapses in our own brains.
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.