In brain imaging, most of the attention understandably goes to the neurons. But the intricate network of blood vessels that bring oxygen to every neural nook and cranny are vitally important as well. For a broad view
of the blood vessels in a living subject, researchers inject an agent that absorbs X-rays into the blood and then snap an X-ray picture.
But for a close-up of the microscopic capillaries that interface with brain cells, different tools are needed. This 2009 image used a scanning electron microscope to zoom in on a slice of a postmortem cortex. It shows the large blood vessels from the surface of the brain at top, and reveals the cascade of smaller and smaller vessels that dive down into the cortex. This type of imaging can't yet be done on a living brain. But if the history of advances in neural imaging is any indication, it's just a matter of time until we come up with something equally amazing.