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Retinofugal pathways in juvenile and adult channel catfish, Ictalurus (Ameiurus) punctatus : An HRP and autoradiographic study
Author(s) -
Rao P. D. Prasada,
Sharma S. C.
Publication year - 1982
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.902100105
Subject(s) - optic tract , biology , anatomy , ictalurus , nucleus , optic nerve , pretectal area , tectum , catfish , suprachiasmatic nucleus , optic chiasm , posterior commissure , midbrain , central nervous system , neuroscience , fish <actinopterygii> , fishery
The retinal projections of the juvenile and adult channel catfish, Ictalurus (Ameiurus) punctatus , were studied by using horseradish peroxidase (HRP) and autoradiography. The contralateral optic tract sends fibers to the suprachiasmatic nucleus (SCN) and divides into lateral (LOT) and medial optic tracts (MOT). In the adult fish, the former is thicker than the latter, whereas in the juvenile form, the reverse is true. The MOT curves laterally and divides into eight to 15 medial fascicles of the optic tract (MFOT). The contralateral optic fibers project to the nucleus opticus dorsolateralis, nucleus of the posterior commissure, nucleus geniculatus lateralis, pretectal nuclear complex, nucleus corticalis, stratum fibrosum et griseum superficiale (SFGS), and a few optic fibers extend into the stratum griseum centrale. The tractus opticus accessorius arises from the postero‐dorsal margin of the LOT and extends ventromedially to project to the nucleus opticus accessorius. At the optic chiasm a few fibers do not decussate, and these fibers project to almost all ipsilateral sites similar to those of the contralateral side, including the optic tectum. The autoradiographic observations substantiated the analysis of optic fiber projections provided by the HRP technique.