We’re stardust, remember?

Looking through the microscope, the vastness of the cosmos stares back at me. Although greatly differing in size, our brain and the universe are more alike than you think. The intricate patterns of vibrant cyan astrocytes stretch out like delicate star-shaped filaments. Grey orbs—the nuclei—drift as silent moons, while magenta nucleoli pulse like quasars, radiating energy at the heart of creation. Golden puncta, scattered like stardust, are RNA—the molecular messengers of life, shining with purpose. This image captures the cellular architecture of the hippocampus, a key brain region for memory and learning, with sub-cellular resolution. At the center of the image lies the pyramidal layer of the hippocampus, where neurons are densely packed in an arc, resembling the swirling core of a galaxy. The improvement in the image resolution was achieved by physically expanding the brain tissue by embedding it in a swellable hydrogel. This imaging technique called expansion microscopy allows us to visualize nanoscale protein structures and RNA simultaneously in the brain tissue. Like the universe, the brain holds infinite mysteries waiting to be explored, and evolving microscopy techniques are pushing us closer to illuminating its vast complexity.