A: Fueling all this brain activity, and the basis for some imaging techniques, is a dense network of delicate blood vessels.

B: Neurons communicate with one another by releasing chemicals, such as dopamine, from pouches called vesicles. The vesicles, seen here in a fibroblast cell, have a geodesic outer coating that eventually pops through the side of the cell and releases its chemical message to be detected by the cell’s neighbors.

C: Our cells are surrounded by a scaffold of proteins that maintains a cell’s shape. Under an electron microscope, protein fibers called actin filaments look like braided ropes.

D: A few years ago, neuroscientists figured out how to take two fluorescent proteins that glowed in green or red and turn them into a rainbow of different colors that can be incorporated into individual neurons. Here the technique is used to stain cells in the cerebellum. The result? A “brainbow.”

Source: Portraits of the Mind: Visualizing the Brain from Antiquity to the 21st Century