Pial surface

The pial surface is the outermost layer of the brain's cortex, composed of thin, delicate tissue called pia mater. It closely follows the folds and grooves of the brain's surface, acting as a protective boundary and supporting blood vessels that supply the brain. This surface is important for brain function because it interfaces with the cerebrospinal fluid and plays a role in how the brain processes information. In neuroimaging and brain studies, the pial surface is a key focus for understanding brain structure and for mapping brain activity.