Browsing Bergen Open Research Archive by Author "Helvik, Jon Vidar"
Now showing items 1-6 of 6
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Heads and tails: The notochord develops differently in the cranium and caudal fin of Atlantic Salmon (Salmo salar, L.)
Kryvi, Harald; Nordvik, Kari; Fjelldal, Per Gunnar; Eilertsen, Mariann; Helvik, Jon Vidar; Støren, Eivind Wilhelm Nagel; Long, John H. (Journal article; Peer reviewed, 2020)While it is well known that the notochord of bony fishes changes over developmental time, less is known about how it varies across different body regions. In the development of the Atlantic salmon, Salmo salar L., cranial ... -
Molecular evidence that only two opsin subfamilies, the blue light- (SWS2) and green light-sensitive (RH2), drive color vision in Atlantic cod (Gadus morhua)
Valen, Ragnhild; Edvardsen, Rolf; Søviknes, Anne Mette; Drivenes, Øyvind; Helvik, Jon Vidar (Peer reviewed; Journal article, 2014-12-31)Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision) including rod opsin only retinas seen in ... -
Neural activation in photosensitive brain regions of Atlantic salmon (Salmo salar) after light stimulation
Eilertsen, Mariann; Clokie, Benjamin G.J.; Ebbesson, Lars; Tanase, Cristina; Migaud, Herve; Helvik, Jon Vidar (Journal article; Peer reviewed, 2021)Photoreceptive inputs to the teleost brain are perceived as image of the visual world and as photo-modulation of neuroendocrine and neuronal signals. The retina and pineal organ are major receptive organs with projections ... -
Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides
Busserolles de, Fanny; Cortesi, Fabio; Helvik, Jon Vidar; Davies, Wayne I. L.; Templin, Rachel M.; Sullivan, Robert K. P.; Michell, Craig T.; Mountford, Jessica K.; Collin, Shaun P.; Irigoien, Xabier; Kaartvedt, Stein; Marshall, Justin (Peer reviewed; Journal article, 2017)Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light ... -
Rhythmic Clock Gene Expression in Atlantic Salmon Parr Brain
Bolton, Charlotte M.; Bekaert, Michaël; Eilertsen, Mariann; Helvik, Jon Vidar; Migaud, Herve (Journal article; Peer reviewed, 2021)To better understand the complexity of clock genes in salmonids, a taxon with an additional whole genome duplication, an analysis was performed to identify and classify gene family members (clock, arntl, period, cryptochrome, ... -
The two-step development of a duplex retina involves distinct events of cone and rod neurogenesis and differentiation
Valen, Ragnhild; Eilertsen, Mariann; Edvardsen, Rolf; Furmanek, Tomasz; Rønnestad, Ivar; van der Meeren, Terje; Karlsen, Ørjan; Nilsen, Tom Ole; Helvik, Jon Vidar (Peer reviewed; Journal article, 2016-08)Unlike in mammals, persistent postembryonic retinal growth is a characteristic feature of fish, which includes major remodeling events that affect all cell types including photoreceptors. Consequently, visual capabilities ...