Structure and Visibility
- The terminal nerve is a microscopic plexus of unmyelinated peripheral nerve fascicles.
- It appears near the cribriform plate and travels posteriorly toward the olfactory trigone, medial olfactory gyrus, and lamina terminalis.
- The nerve is often overlooked in autopsies due to its thinness and is often torn out when exposing the brain.
- Careful dissection is necessary to visualize the nerve.
- The nerve is not commonly mentioned in anatomy textbooks.
Development
- The zebrafish has been used as a developmental model in studying the terminal nerve.
- The connections between the terminal nerve and the olfactory system have been extensively studied in human embryos.
- The nerve enters the brain at stages 17 and 18 from olfactory origins.
Function
- The terminal nerve is not connected to the olfactory bulb, suggesting it may be vestigial or involved in sensing pheromones.
- It projects to the medial and lateral septal nuclei and the preoptic areas, which are involved in regulating sexual behavior in mammals.
- A study in hamsters found that mating is reduced when the terminal nerve is severed.
Additional Images
- Three forms of the nerve can be observed on the underside of human brains.
- The gyrus rectus can be seen at the anterior center when viewing the brain from below.
Related Topic
- Vomeronasal organ
The terminal nerve, also known as cranial nerve 0 or simply as CN 0, is a nerve that was not included in the seminal classification of the cranial nerves as CN I through CN XII but is now generally classified as a cranial nerve. It was discovered by German scientist Gustav Fritsch in 1878 in the brains of sharks. It was first found in humans in 1913. A 1990 study has indicated that the terminal nerve is a common finding in the adult human brain. The nerve has been called unofficially by other names, including cranial nerve XIII, zero nerve, nerve N, and NT.
| Cranial nerve zero | |
|---|---|
 Left The terminal nerve as it is shown on the ventral side of a dog-fish brain. (Topmost label) | |
| Details | |
| Identifiers | |
| Latin | nervus terminalis |
| TA98 | A14.2.01.002 |
| TA2 | 6179 |
| FMA | 76749 |
| Anatomical terminology | |
