Medial olfactory stria

The medial olfactory stria is a small and variable bundle of secondary olfactory fibres that passes medially from the olfactory trigone. It carries processed olfactory information from the olfactory bulb mainly toward the medial part of the olfactory tubercle and the ventral taenia tecta, which are regions involved in the central processing of smell.

The anatomy of this pathway in humans is not completely established. The review in the reference section below, distinguishes this pathway from the historically described “classic medial olfactory stria,” which was previously thought to continue farther medially toward the septal area. Evidence reviewed in the paper suggests that this classic pathway may not contain secondary olfactory fibres. In fact, the structure often identified macroscopically as the classic medial olfactory stria may actually represent the medial olfactory gyrus.

More recent human tractography has demonstrated a medial bundle terminating around the olfactory tubercle, although current MRI cannot reliably distinguish this region from the adjacent ventral taenia tecta. The review therefore supports a more restricted concept of the medial olfactory stria as a short medial olfactory projection, rather than a major pathway extending to the septal area.

In simple terms: Olfactory trigone → medial olfactory stria → medial olfactory tubercle / ventral taenia tecta

This contrasts with the lateral olfactory stria, which carries most secondary olfactory fibres toward the primary olfactory cortical regions.