Afferent and efferent connections of the nucleus prethalamicus in the yellowfin goby Acanthogobius flavimanus. Issue 1 (27th May 2020)

• Record Type: Journal Article
• Authors: Hagio, Hanako; Kawaguchi, Masahumi; Abe, Hideki; Yamamoto, Naoyuki
• Is Part Of: Journal of comparative neurology. Volume 529:Issue 1(2021)
• Page Start: 87
• Page End: 110
• Publication Date: 2020-05-27
• Subjects: acanthopterygian fish -- cerebellum -- nucleus prethalamicus -- optic tectum -- telencephalon -- teleosts -- visual pathway; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24935
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: The nucleus prethalamicus (PTh) receives fibers from the optic tectum and then projects to the dorsal telencephalon in the yellowfin goby Acanthogobius flavimanus . However, it remained unclear whether the PTh is a visual relay nucleus, because the optic tectum receives not only visual but also other sensory modalities. Furthermore, precise telencephalic regions receiving prethalamic input remained unknown in the goby. We therefore investigated the full set of afferent and efferent connections of the PTh by direct tracer injections into the nucleus. Injections into the PTh labeled cells in the optic tectum, ventromedial thalamic nucleus, central and medial parts of the dorsal telencephalon, and caudal lobe of the cerebellum. We found that the somata of most tecto‐prethalamic neurons are present in the stratum periventriculare. Their dendrites ascend to reach the major retinorecipient layers of the tectum. The PTh is composed of two subnuclei (medial and lateral) and topographic organization was appreciated only for tectal projections to the lateral subnucleus (PTh‐l), which also receives sparse retinal projections. In contrast, the medial subnucleus receives fibers only from the medial tectum. We found that the PTh projects to nine subregions in the dorsal telencephalon and four in the ventral telencephalon. Furthermore, cerebellar injections revealed that cerebello‐prethalamic fibers cross the midline twice to innervate the PTh‐l on both sides. The present study is the first detailed report on the full set of the connections of PTh, which suggests that the PTh relays visual information from the optic tectum to the telencephalon. Abstract : The nucleus prethalamicus of the yellowfin goby relays visual information from the optic tectum to as many as 13 regions of the telencephalon that is amazingly well compartmentalized in the goby. The goby is a promising model fish for studying telencephalic circuitries involved in the processing of visual information.