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The olfactoretinalis system = terminal nerve?
T Szabo1, S Blähser, J P Denizot
1Département de Neurophysiologie Sensorielle, C.N.R.S., Gif sur Yvette, France.
Neuroreport
|February 1, 1991
Summary
The terminal nerve (nT) is distinct from the olfactoretinal system (ORS) in gymnotids. Immunohistochemistry shows nT originates rostrally and projects to the anterior nostril, unlike the ORS.
Area of Science:
- Neuroscience
- Comparative Anatomy
- Ichthyology
Background:
- The olfactoretinal system (ORS) has been previously considered synonymous with the terminal nerve (nT) in gymnotid species.
- Understanding the distinct anatomical and projectional characteristics of neural systems is crucial for accurate neuroanatomical mapping.
Purpose of the Study:
- To differentiate the terminal nerve (nT) from the olfactoretinal system (ORS) in gymnotid species using immunohistochemistry.
- To clarify the anatomical origins, pathways, and projections of both the nT and ORS.
Main Methods:
- Immunohistochemistry was employed to visualize specific neuronal markers.
- Analysis focused on identifying distinct ganglia, fibre bundles, and projection targets of the nT and ORS.
Main Results:
- Immunohistochemistry revealed a distinct terminal nerve (nT) separate from the olfactoretinal system (ORS).
- The ORS ganglion (NOR) contains FMRF-amide immunoreactive neurons projecting to the olfactory bulb and optic nerve, but not the olfactory epithelium.
- The nT is a substance P or GnRH immunoreactive fibre bundle originating from a rostral ganglion, projecting to the anterior nostril epithelium and olfactory bulb glomeruli.
Conclusions:
- The terminal nerve (nT) is a distinct cranial nerve in gymnotids, separate from the olfactoretinal system (ORS).
- The ORS should no longer be considered the terminal nerve based on these findings.
- This study provides a clearer neuroanatomical distinction between these two systems in gymnotids.