By John Ngai/ NIH Director's Blog
Silas Busch at the University of Chicago captured this slightly eerie scene, noting it reminded him of people shuffling through the dark of night. What you’re really seeing are some of the largest neurons in the mammalian brain, known as Purkinje cells. The photo won first place this year in the Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative’s annual Show Us Your BRAINs! Photo and Video Contest.
While humans have them, too, the Purkinje cells pictured here are in the brain of a mouse. The head-like shapes you see in the image are the so-called soma or the neurons’ cell bodies. Extending downwards are the heavily branched dendrites, which act like large antennae, receiving thousands of inputs from the rest of the body.
One reason this picture is such a standout, explains Busch, is because of what you don’t see. You’ll notice that only a few cells are fluorescently labeled and therefore lit up in green, leaving the rest in shadows. As a result, it’s possible to trace the detailed branches of individual Purkinje cells and make out their intricate forms. As it turns out, this ability to trace Purkinje cells so precisely led Busch, who is a graduate student in Christian Hansel’s lab focused on the neurobiology of learning and memory, to a surprising discovery, which the pair recently reported in Science.
Purkinje cells connect to nerve fibers that “climb up” from the brain stem, which connects your brain and spinal cord to help control breathing, heart rate, balance, and more. Scientists thought that each Purkinje cell received only one of these climbing fibers from the brain stem on its single primary branch.