Splashes of Somatostatin

What am I looking at?

This image shows a 1.5-millimeter-thick horizontal slice through the brain of a mouse, with neurons that produce somatostatin in purple (1) and pyramidal neurons in green (2). You can see that the somatostatin neurons, while enriched in some areas of the brain, are present throughout the organ. In contrast, while the pyramidal neurons are also widespread, they form much more distinct pathways and groupings (3).

Biology in the background

Somatostatin is an inhibitory neurotransmitter that is involved in many different brain processes, including memory formation and hormone regulation. Due to its many functions, somatostatin is produced all over the brain.

Pyramidal neurons are one of the most common types of neurons in the brain and are named for their pyramid-shaped cell bodies. These neurons are involved in a wide range of functions as well, including memory, movement, and the processing of sensory information. However, you can see in this image that pyramidal neurons tend to form more distinct pathways and groupings than somatostatin-producing neurons do.

The location and architecture of these two kinds of neurons are linked to their function. Somatostatin is considered a neuromodulator, meaning it helps direct other neurons by providing inhibitory input when needed. So it makes sense that the neurons that produce it would be spread across the brain. Pyramidal neurons are often the target of this type of modulation and use the input to accomplish their complex functions within the brain.

In both mice and humans, the cell bodies of somatostatin-producing neurons can grow up to 15 micrometers across, or roughly five times smaller than the width of a human hair.

Technique

These images were created using confocal microscopy.