Spectral Sensitivity of Scorpion Eyes and the Possible Role of Shielding Pigment Effect

1968 ◽  
Vol 49 (1) ◽  
pp. 95-105
Author(s):  
L. MACHAN
Keyword(s):  
Spectral Sensitivity ◽  
Dark Adaptation ◽  
Lateral Eye ◽  
Ultraviolet Sensitivity ◽  
Marked Drop

1. The lateral eye shows one maximum in the ultraviolet and another in the blue-green region of the spectrum, probably attributable to two receptor types. 2. Light-adapted lateral eyes show the peculiar effect of a marked drop in ultraviolet sensitivity, irrespective of the colour of the adapting light. 3. Absorption by shielding pigment of the lateral eye is slightly selective in the short wavelengths. 4. The median eye has one maximum in the blue-green, violet sensitivity being apparent only with prolonged dark-adaptation. 5. Absorption by the shielding pigment of the median eye appears to be non-selective.

scholarly journals Properties of visual cells in the lateral eye of Limulus in situ.

1975 ◽  
Vol 66 (3) ◽  
pp. 303-326 ◽  
Author(s):  
E Kaplan ◽  
R B Barlow
Keyword(s):  
Optic Nerve ◽  
Spectral Sensitivity ◽  
Dark Adaptation ◽  
The Other ◽  
Low Light ◽  
Visual Cells ◽  
Increment Threshold ◽  
Lateral Eye ◽  
Nerve Recordings

Excitatory properties of visual cells in the lateral eye of Limulus, investigated by optic nerve recordings in situ, differ significantly from the properties of cells in the classical, excised eye preparation. The differences suggest the possibility that two receptor mechanisms function in the eye in situ: one mechanism encodes low light intensities and the other responds to high intensities. The two mechanisms enable each ommatidium to respond over an intensity range of approximately 10 log units. This hypothesis was tested by measuring the increment threshold and the spectral sensitivity, by studying light and dark adaptation, and by analyzing the variability of the impulse discharge. Although the results do not conclusively identify two receptor mechanisms, they indicate that a process or a part of a process that functions in the eye in situ is abolished by excising the eye or cutting off its blood supply.

The spectral sensitivity of the human electroretinogram during the temporal course of dark-adaptation

1966 ◽  
Vol 6 (9-10) ◽  
pp. 507-516 ◽  
Author(s):  
Allen M. Granda ◽  
William R. Biersdorf
Keyword(s):  
Spectral Sensitivity ◽  
Dark Adaptation ◽  
Temporal Course

Spectral sensitivity of the electroretinogram b-wave in dark-adapted goldfish

1988 ◽  
Vol 1 (2) ◽  
pp. 159-168 ◽  
Author(s):  
Jonathan D. Nussdorf ◽  
Maureen K. Powers
Keyword(s):  
Absorption Spectrum ◽  
Spectral Sensitivity ◽  
Neural Activity ◽  
Dark Adaptation ◽  
Carassius Auratus ◽  
Action Spectrum ◽  
Absolute Threshold ◽  
Selective Loss

AbstractThe action spectrum of the ERG b-wave was measured under dark-adapted conditions in intact goldfish (Carassius auratus). It is substantially broader than the absorption spectrum of goldfish rod porphyropsin. Neither prolonged dark adaptation nor removal of possible efferent neural activity affected its shape. Moreover, a 682-nm background did not produce a selective loss of sensitivity to long wavelengths. The results imply that the spectral sensitivity of the b-wave in dark-adapted goldfish reflects the influence of at least two photoreceptor types which act as a single univariant mechanism near absolute threshold.

Alpha asymmetry as a function of cognitive mode: The role of lateral eye movements

1981 ◽  
Vol 13 (2-3) ◽  
pp. 137-141 ◽  
Author(s):  
Linda R. Warren ◽  
Eric S. Haueter
Keyword(s):  
Eye Movements ◽  
Alpha Asymmetry ◽  
Lateral Eye ◽  
Cognitive Mode

Somatomedin synthesis by a subclone of Buffalo rat liver cells. Influence of divalent cations on rIGF-II release

1985 ◽  
Vol 110 (2) ◽  
pp. 232-238
Author(s):  
Peter W. Mayer ◽  
Don S. Schalch
Keyword(s):  
Rat Liver ◽  
Cell Damage ◽  
Divalent Cations ◽  
Nutritional Factors ◽  
Factor Ii ◽  
Wide Range ◽  
Rat Liver Cells ◽  
Concomitant Reduction ◽  
Marked Drop

Abstract. Previous studies have provided evidence that biosynthesis and secretion of somatomedin (SM) is not only hormone dependent, but also modulated by nutritional factors. Little is known, however, about the role of divalent cations in these processes. A subclone of Buffalo rat liver (BRL) cells, known to secrete rat insulin-like growth factor-II (rIGF-II) into serum-free medium, was used to define the influence of Ca2+, Mg2+ and Zn2+ on this function. The secretion of rIGF-II by subclone BRL-3SC appears to be quite stable in minimal essential medium (MEM) over a wide range in Ca2+ concentrations (0.18–3.0 mm) but is reduced to only 8% of controls in the absence of Ca2+ (P <0.01). Reducing, and even eliminating, the extracellular concentration of Mg2+ alone caused no change in basal rIGF-II release, while simultaneously decreasing Mg2+ and Ca2+ results in a marked drop in the secretion of this SM, reaching a nadir of 38% of controls in the absence of Mg2+ (P <0.001). A Mg2+ concentration of 10 mm, or 25 times 'normal', did not alter the basal secretion of rIGF-II. Eliminating the trace amount (0.8 nm) of Zn2+ in MEM by chelation with EDTA decreased rIGF-II secretion to 62% of control levels (P<0.01), while increasing the concentration of this cation to 3 mm did not alter the basal release of this SM. Decreased rIGF-II release in the presence of EGTA and EDTA is not due to irreversible cell damage since the secretion of this SM was restored to normal during subsequent reincubation in MEM alone. These studies indicate that normal rIGF-II secretion by BRL-3SC cells occurs only at concentrations of Ca2+, Mg2+ (in the presence of reduced Ca2+) and Zn2+ above certain threshold levels. Moreover, reduced Mg2+ alone, without a concomitant reduction in Ca2+, does not decrease rIGF-II release, attesting to the known interaction of these cations in a variety of intracellular processes. Concentrations of these three cations considerably higher than 'normal' appear to have no significant effect on basal rIGF-II secretion.

scholarly journals Optimal timing of retinal scanning during dark adaptation, in the presence of fixation on a target: the role of pupil size dynamics

2014 ◽  
Vol 19 (10) ◽  
pp. 106014 ◽  
Author(s):  
Boris I. Gramatikov ◽  
Kristina Irsch ◽  
David Guyton
Keyword(s):  
Dark Adaptation ◽  
Pupil Size ◽  
Optimal Timing

Spectral Sensitivity Comparison of Lateral Eye and Ocellus of Horseshoe Crab*

1964 ◽  
Vol 54 (9) ◽  
pp. 1167 ◽  
Author(s):  
Abner B. Lall ◽  
Robert M. Chapman
Keyword(s):  
Spectral Sensitivity ◽  
Horseshoe Crab ◽  
Lateral Eye

Visions of vision: Studies of the horseshoe crab compound eye

1992 ◽  
Vol 50 (1) ◽  
pp. 488-489
Author(s):  
Steven C. Chamberlain
Keyword(s):  
Horseshoe Crab ◽  
Light Adaptation ◽  
Compound Eye ◽  
Visually Guided ◽  
Morphological Process ◽  
Morphological Studies ◽  
Visual Processes ◽  
Lateral Eye ◽  
The Brain

The lateral eye of the horseshoe crab, Limulus polyphemus, is an important model system for studies of visual processes such as phototransduction, lateral inhibition, and light adaptation. It has also been the system of choice for pioneering studies of the role of circadian efferent input from the brain to the eye. For example, light and efferent input interact in controlling the daily shedding of photosensitive membrane and photomechanical movements. Most recently, modeling efforts have begun to relate anatomy, physiology and visually guided behavior using parallel computing. My laboratory has pursued collaborative morphological studies of the compound eye for the past 15 years. Some of this research has been correlated structure/function studies; the rest has been studies of basic morphology and morphological process.

scholarly journals Night-time Lookout Duty: The Role of Ambient Light Levels and Dark Adaptation

2012 ◽  
Vol 65 (4) ◽  
pp. 589-602 ◽  
Author(s):  
Tony Wynn ◽  
Peter A. Howarth ◽  
Bert R. Kunze
Keyword(s):  
Dark Adaptation ◽  
Probability Of Detection ◽  
Working Environment ◽  
Ambient Light ◽  
Night Time ◽  
Lighting Conditions ◽  
Light Levels ◽  
Ambient Lighting ◽  
Small Craft

The aim of this research was to clarify and quantify the demands of the working environment and watch-keeping regime for large commercial ships in relation to dark adaptation. The night lookout task requires the identification of the relatively bright navigational lights of other ships against the dark background of the sky and sea. The probability of detection is determined by the ambient lighting conditions on the bridge and the dark adapted state of vision. Light levels were such that threshold sensitivity (after 15 minutes) was reduced by around 2 log units in comparison to complete darkness. This has implications for the effective range of navigational lights at sea as defined in regulations. The intensity and position of navigation lights on larger vessels is such that the sensitivity of the eye under typical bridge conditions is likely to be sufficient for their visibility to be acceptable. This may not be the case for less well lit small craft.

Sign in / Sign up

Export Citation Format

Share Document