Habenula

The habenula (diminutive of Latin , meaning "rein") is a small bilateral neuronal structure in the brain of vertebrates, that has also been called a microstructure since it is no bigger than a pea. The naming as "little rein" describes its elongated shape in the epithalamus, where it borders the third ventricle, and lies in front of the pineal gland.

commissure of two habenulae, left and right

structure in the brain