An ascending visual pathway to the dorsal telencephalon through the optic tectum and nucleus prethalamicus in the yellowfin goby Acanthogobius flavimanus (Temminck & Schlegel, 1845). Issue 10 (22nd April 2018)

• Record Type: Journal Article
• Authors: Hagio, Hanako; Sato, Moe; Yamamoto, Naoyuki
• Is Part Of: Journal of comparative neurology. Volume 526:Issue 10(2018)
• Page Start: 1733
• Page End: 1746
• Publication Date: 2018-04-22
• Subjects: visual pathways -- retina -- optic tectum -- nucleus prethalamicus -- teleosts; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24444
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: Dual visual pathways reaching the telencephalon appear to be an ancient vertebrate trait, but some teleost fish seem to possess only one pathway via the optic tectum. We undertook the present study to determine if and when this loss occurred during evolution. Tracer injection experiments to the optic nerve, the optic tectum, and the dorsal telencephalon were performed in the present study, to investigate ascending visual pathways to the dorsal telencephalon in an acanthopterygian teleost, the yellowfin goby Acanthogobius flavimanus (Temminck & Schlegel, 1845). We confirmed the presence of a nucleus prethalamicus (PTh) in the goby, which has been convincingly identified only in holocentrids, suggesting that this nucleus is present in other acanthopterygians. We found that the optic tectum projects to the PTh bilaterally. The PTh projects in turn to the dorsal telencephalon, ipsilaterally. These results suggest that the yellowfin goby possesses only an extrageniculate‐like pathway, while a geniculate‐like pathway could not be identified. This situation is common with that of holocentrids and may be a character common in acanthopterygians. It is possible that a geniculate‐like system was lost in the common ancestor of acanthopterygians, although the scenario for the evolution of ascending visual systems in actinopterygians remains uncertain due to the lack of precise knowledge in a number of actinopterygian taxons. Abstract : The present study suggests that the yellowfin goby possesses only one ascending visual pathway via the optic tectum and the nucleus prethalamicus (PTh) to the dorsal telencephalon, which is similar to the extrageniculate system. The present study also suggests that the lack of geniculate‐like pathway is a feature shared in acanthopterygians. Comparisons of the present results with the known visual pathways in other actinopterygians suggest multiple scenarios in the evolution of visual pathways in actinopterygian fishes.