Nucleus isthmi in goldfish: in vitro recordings and fiber connections revealed by HRP injections
| Autor: | John T. Schmidt, King Wm |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Superior Colliculi
Physiology Central nervous system Horseradish peroxidase Injections Membrane Potentials Nerve Fibers Goldfish medicine Tegmentum Animals Visual Pathways Pretectal area Horseradish Peroxidase Brain Mapping biology Chemistry Optic Nerve Anatomy Sensory Systems Electric Stimulation Electrophysiology medicine.anatomical_structure nervous system Optic nerve biology.protein sense organs Tectum Nucleus |
| Zdroj: | Visual neuroscience. 10(3) |
| ISSN: | 0952-5238 |
| Popis: | Recordings of field potentials in nucleus isthmi (NI) were obtained in an in vitro preparation of goldfish brain using a lateral approach. Horseradish peroxidase (HRP) was injected from recording electrodes to verify recordings within the nucleus and to label axonal pathways and cell bodies. Activity in NI was repetitive and could be elicited by stimulation of the optic nerve, tectum, pretectum, or tectobulbar tract. Spontaneous activity was present in some preparations and consisted of bursts with intervening silent periods. Anatomical and electrophysiological evidence indicated that the primary isthmotectal pathway is composed of fine fibers that exit NI rostrally and pass through pretectum to enter tectum rostrally. An afferent pathway consisting of both fine- and large-diameter fibers entered NI ventromedially; the large diameter axons have been previously reported in percomorph fishes, but were not thought to be present in cyprinids such as goldfish. The large diameter axons arise from labeled cell bodies in the region of the lateral thalamic nucleus. No labeled cell bodies were seen in ipsilateral nucleus pretectalis superficialis, pars magnocellularis, where they are seen in percomorphs. The fine axons, which have not been reported in percomorph fishes, were shown to arise from tectal bipolar (type VI) neurons. As in percomorphs, tectal type XIV neurons were also labeled. This and corroborating recordings from nucleus isthmi constitute the first demonstration of a tectoisthmic projection in a cyprinid fish. |
| Databáze: | OpenAIRE |
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