pyramidal (projection) neuron

A pyramidal neuron is one of the main workhorse brain cells of the cortex — the thin, wrinkled outer sheet of the brain where much of our thinking, sensing, and planning happens. Its name comes from the shape of its cell body, the central bulb that holds the cell's life-support machinery: instead of being round, that body is triangular, like a tiny pyramid pointing toward the brain's surface. From the pointed top sprouts one thick branch, and from the wide base spread several more, all of them bushy with even finer twigs that catch incoming signals. With this distinctive triangular outline, pyramidal neurons are some of the easiest brain cells to recognize under a microscope.

What makes them especially important is that they are projection neurons — cells whose job is to send messages far away rather than just to their immediate neighbors. Each one grows a single long output cable, called an axon, that can stretch across the brain or all the way down the spinal cord, sometimes for many centimeters. Along this cable the neuron fires brief electrical pulses to pass its message on, often to a completely different brain region or even out to the muscles. So while smaller local cells mostly chat within one patch of tissue, pyramidal neurons are the long-distance lines that let widely separated parts of the nervous system talk to one another, carrying the commands behind movement, perception, and thought.