The fetal and neonatal brain is a rapidly changing, developing structure.

A fetal brain, on the other hand, is designed to make new connections.

This begins, interestingly, even before the fetal brain can register the differences between light and dark.

Normally, these organized bundles appear very early in the developing fetal brain.

Up to this time, the fetal brain normally has a smooth appearance.

On their surface was a protein called nestin, until then thought to exist only in fetal brains.

In some cases, where the pregnancy was difficult, there could have been damage to the fetal brain.

This is in the middle of the fetal brain.

The fetal brain may create these cysts as a normal part of development.