A Multitude of Pyramids

What am I looking at?

This image is a 1-millimeter-thick coronal slice (from top to bottom) through the brain of a mouse, with the pyramidal neurons labeled in orange. These neurons are concentrated in the cerebral cortex (1), the hippocampus (2), and the pyramidal tract (3).

Biology in the background

Pyramidal neurons are a very common type of neuron in the brain. Their cell bodies have a unique pyramidal shape that is the source of their name. They make up about two-thirds of all neurons in the cerebral cortex of mammals, making them important for many cognitive processes, including memory. So it makes sense that the hippocampus, the memory center of the brain, is full of pyramidal neurons.

Pyramidal neurons also make up the pyramidal tract. This pathway is responsible for carrying signals from the cerebral cortex, generally considered the location where conscious thought is generated, to the spinal cord, which can then pass those signals on to the rest of the body.

In both humans and mice, the cell bodies of these neurons are about 20 micrometers across, or roughly four times smaller than the width of a human hair.

Technique

These images were created using confocal microscopy.