Effect of Light Deprivation on Fine Structural Changes in the Optic Tectum of the Rainbow Trout (Salmo gairdneri, Rich.) during Ontogenesis

1979 ◽  
Vol 2 (1) ◽  
pp. 19-24 ◽  
Author(s):  
G. Jeserich ◽  
H. Rahmann
Keyword(s):  
Rainbow Trout ◽  
Optic Tectum ◽  
Structural Changes ◽  
Salmo Gairdneri ◽  
Light Deprivation ◽  
Effect Of Light

Ontogeny of Visual Acuity of Rainbow Trout Under Normal Conditions and Light Deprivation

Behaviour ◽  
1979 ◽  
Vol 68 (3-4) ◽  
pp. 315-322 ◽  
Author(s):  
I. Zeutzius ◽  
G. Jeserich ◽  
H. Rahmann
Keyword(s):  
Visual Acuity ◽  
Rainbow Trout ◽  
Visual Angle ◽  
Resolving Power ◽  
Salmo Gairdneri ◽  
Light Deprivation ◽  
Tectum Opticum ◽  
Rearing Conditions ◽  
Severe Impairment ◽  
One Year

AbstractThe development of visual acuity (minimum separable visual angle) in rainbow trout (Salmo gairdneri) was investigated from hatching to one year old trout by eliciting optomotor reactions in an optokinetic drum. I. The first optomotor responses were found 10 days after hatching with a visual angle of 30° of arc. Then a rapid increase in the visual resolving power occurs leading to a visual angle of about 1° at the end of the larval period. Up to the age of one year the visual angle of rainbow trout improves slightly to final 14' of arc. 2. Light deprivation during rearing causes a severe impairment ot visual acuity during the first 40 days after hatching (best visual angle only 2°05' of arc). 3. The results are discussed with respect to synaptogenetical and biochemical findings in the tectum opticum of rainbow trout under the same rearing conditions.

scholarly journals An Endogenous Crepuscular Rhythm Of Rainbow Trout (Salmo Gairdneri) Photomechanical Movements

1982 ◽  
Vol 96 (1) ◽  
pp. 377-388 ◽  
Author(s):  
R. H. Douglas
Keyword(s):  
Rainbow Trout ◽  
Direct Effect ◽  
Light Adaptation ◽  
Endogenous Rhythm ◽  
Salmo Gairdneri ◽  
Natural Light ◽  
Behavioural Pattern ◽  
Two Peaks ◽  
Endogenous Component ◽  
Effect Of Light

1. The position of the epithelial pigment and cones in the retina of Salmo gairdneri was determined during extended periods of darkness in fish entrained to both artificial and natural light/dark cycles. 2. An endogenous rhythm of such photomechanical movements, unique among species so far examined, was observed in both groups of fish, with two peaks of light adaptation coincident with dawn and dusk. 3. It is suggested that such an apparently non-adaptive physiological rhythm is related to the behavioural pattern of trout and reveals a basic crepuscular organisation. 4. No endogenous rhythm was observed in continual light. 5. These results suggest that control of photomechanical changes in rainbow trout has two components: an endogenous component, that causes the bimodal pattern in maintained darkness, and a direct effect of light, that maintains light adaptation throughout a normal day. Note:

scholarly journals The Function of Photomechanical Movements in the Retina of the Rainbow Trout (Salmo Gairdneri)

1982 ◽  
Vol 96 (1) ◽  
pp. 389-403 ◽  
Author(s):  
R. H. DOUGLAS
Keyword(s):  
Rainbow Trout ◽  
Dark Adaptation ◽  
Visual Pigment ◽  
Time Course ◽  
Temporal Correlation ◽  
Salmo Gairdneri ◽  
Direct Sunlight ◽  
Pigment Concentrations ◽  
Wave Sensitivity ◽  
Effect Of Light

1. The function of photomechanical movements in the retina of rainbow trout (Salmo gairdneri) was investigated by determining both the effect of light on the level of extractable visual pigment, and the electroretinographic b-wave sensitivity, during various stages of photomechanical light and dark adaptation. 2. Dark-adapted fish, light-adapted fish, and dark-adapted fish exposed to ten minutes direct sunlight had on average visual pigment concentrations of 100, 82 and 36% respectively. 3. The intensity of illumination required to bleach a specified amount of visual pigment in the light-adapted retina was found to be 1.29 log units higher than that needed to bleach the same amount of visual pigment in a dark-adapted eye. 4. The level of extractable visual pigment was observed to be relatively constant over natural twilight periods. 5. A close temporal correlation was observed between the time course of electroretinographic adaptation, measured by the b-wave sensitivity, and photomechanical changes. 6. All these observations tend to support the hypothesis that photomechanical movements serve, at least in part, to protect the rod visual pigment from overstimulation in the light-adapted retina.

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