Retinal specializations in the blue marlin: eyes designed for sensitivity to low light levels

2003 ◽  
Vol 54 (4) ◽  
pp. 333 ◽  
Author(s):  
Kerstin A. Fritsches ◽  
N. Justin Marshall ◽  
Eric J. Warrant
Keyword(s):  
Ganglion Cells ◽  
Light Level ◽  
Cone Photoreceptors ◽  
Low Light ◽  
Absolute Size ◽  
Blue Marlin ◽  
Optical Sensitivity ◽  
Makaira Nigricans ◽  
Light Levels ◽  
Important Sense

The large eyes and well-developed visual system of billfishes suggest that vision is an important sense for the detection and interception of prey and lures. Investigations of visual abilities in these large pelagic fishes are difficult, however anatomical studies of billfish eyes and retinas allow prediction of a number of visual capabilities. From the density of ganglion cells in the blue marlin (Makaira nigricans) retina, visual acuities of less than 10 cycles per degree were derived, a surprisingly low visual resolution given the absolute size of the marlin eye. Cone photoreceptors, on the other hand, were present in high densities, resulting in a presumed summation of cones to ganglion cells at a ratio of 40 : 1, even in the area of best vision. The optical sensitivity of the marlin eye was high owing to the large dimensions of the cone photoreceptors. These results indicate that the marlin eye is specifically adapted to cope with the low light levels encountered during diving. Since the marlin is likely to use its vision at depth, it is suggested that this line of research could help estimate the limits of vertical distribution based on light level.

scholarly journals The visual ecology of a deep-sea fish, the escolar Lepidocybium flavobrunneum (Smith, 1843)

2014 ◽  
Vol 369 (1636) ◽  
pp. 20130039 ◽  
Author(s):  
Eva Landgren ◽  
Kerstin Fritsches ◽  
Richard Brill ◽  
Eric Warrant
Keyword(s):  
Surface Waters ◽  
Deep Sea ◽  
Ganglion Cells ◽  
Optical Path Length ◽  
Predatory Fish ◽  
Flicker Fusion Frequency ◽  
Optical Sensitivity ◽  
Light Levels ◽  
Electrophysiological Recordings ◽  
Maximal Absorption

Escolar ( Lepidocybium flavobrunneum , family Gempylidae) are large and darkly coloured deep-sea predatory fish found in the cold depths (more than 200 m) during the day and in warm surface waters at night. They have large eyes and an overall low density of retinal ganglion cells that endow them with a very high optical sensitivity. Escolar have banked retinae comprising six to eight layers of rods to increase the optical path length for maximal absorption of the incoming light. Their retinae possess two main areae of higher ganglion cell density, one in the ventral retina viewing the dorsal world above (with a moderate acuity of 4.6 cycles deg −1 ), and the second in the temporal retina viewing the frontal world ahead. Electrophysiological recordings of the flicker fusion frequency (FFF) in isolated retinas indicate that escolar have slow vision, with maximal FFF at the highest light levels and temperatures (around 9 Hz at 23°C) which fall to 1–2 Hz in dim light or cooler temperatures. Our results suggest that escolar are slowly moving sit-and-wait predators. In dim, warm surface waters at night, their slow vision, moderate dorsal resolution and highly sensitive eyes may allow them to surprise prey from below that are silhouetted in the downwelling light.

scholarly journals Interactive effects of temperature and light on reattachment success in the brown alga Fucus radicans

2019 ◽  
Vol 62 (1) ◽  
pp. 43-50
Author(s):  
Ellen Schagerström ◽  
Tiina Salo
Keyword(s):  
High Temperature ◽  
Water Temperature ◽  
Asexual Reproduction ◽  
Net Primary Production ◽  
Light Level ◽  
Interactive Effects ◽  
Low Light ◽  
Dispersal Capacity ◽  
Light Levels ◽  
The Baltic

Abstract Fucus radicans is an endemic habitat-forming brown macroalga in the Baltic Sea that commonly complements its sexual reproduction with asexual reproduction. Asexual reproduction in F. radicans takes place through formation of adventitious branches (hereafter fragments), but the exact mechanisms behind it remain unknown. We assessed experimentally the importance of two environmental factors determining the re-attachment success of F. radicans fragments. By combining different light conditions (daylength and irradiance; high or low light) and water temperature (+14°C and +4°C), we mimicked ambient light and temperature conditions of winter, spring/autumn and summer for F. radicans. Fragments were able to re-attach in all tested conditions. Temperature and light had an interactive impact on re-attachment: the combination of high temperature and high light level resulted in the highest re-attachment success, while light level had no effects on re-attachment success in cooler water temperature and the re-attachment success in high temperature under low light levels was very low. The results suggest that rhizoid formation, and thus re-attachment success, may depend on the net primary production (metabolic balance) of the fragment. However, whether the re-attachment and asexual reproduction success simply depends on photosynthetic capacity warrants further mechanistic studies. Understanding the mechanisms of asexual reproduction in F. radicans is important in order to assess the dispersal capacity of this foundation species.

scholarly journals Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina

2019 ◽  
Vol 99 (3) ◽  
pp. 1527-1573 ◽  
Author(s):  
Wallace B. Thoreson ◽  
Dennis M. Dacey
Keyword(s):  
Color Vision ◽  
Ganglion Cells ◽  
Color Perception ◽  
Visible Spectrum ◽  
Cell Types ◽  
Photon Flux ◽  
Low Light ◽  
Vertebrate Retina ◽  
Light Levels ◽  
Synaptic Interactions

Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.

Light adaptation in the primate retina: Analysis of changes in gain and dynamics of monkey retinal ganglion cells

1990 ◽  
Vol 4 (1) ◽  
pp. 75-93 ◽  
Author(s):  
Keith Purpura ◽  
Daniel Tranchina ◽  
Ehud Kaplan ◽  
Robert M. Shapley
Keyword(s):  
Retinal Ganglion Cells ◽  
Negative Feedback ◽  
Light Adaptation ◽  
Ganglion Cells ◽  
Human Subjects ◽  
Light Level ◽  
Retinal Ganglion ◽  
M Cell ◽  
Feedback Model ◽  
Light Levels

AbstractThe responses of monkey retinal ganglion cells to sinusoidal stimuli of various temporal frequencies were measured and analyzed at a number of mean light levels. Temporal modulation tuning functions (TMTFs) were measured at each mean level by varying the drift rate of a sine-wave grating of fixed spatial frequency and contrast. The changes seen in ganglion cell temporal responses with changes in adaptation state were similar to those observed in human subjects and in turtle horizontal cells and cones tested with sinusoidally flickering stimuli; “Weber's Law” behavior was seen at low temporal frequencies but not at higher temporal frequencies. Temporal responses were analyzed in two ways: (1) at each light level, the TMTFs were fit by a model consisting of a cascade of low- and high-pass filters; (2) the family of TMTFs collected over a range of light levels for a given cell was fit by a linear negative feedback model in which the gain of the feedback was proportional to the mean light level. Analysis (1) revealed that the temporal responses of one class of monkey ganglion cells (M cells) were more phasic at both photopic and mesopic light levels than the responses of P ganglion cells. In analysis (2), the linear negative feedback model accounted reasonably well for changes in gain and dynamics seen in three P cells and one M cell. From the feedback model, it was possible to estimate the light level at which the dark-adapted gain of the cone pathways in the primate retina fell by a factor of two. This value was two to three orders of magnitude lower than the value estimated from recordings of isolated monkey cones. Thus, while a model which includes a single stage of negative feedback can account for the changes in gain and dynamics associated with light adaptation in the photopic and mesopic ranges of vision, the underlying physical mechanisms are unknown and may involve elements in the primate retina other than the cone.

scholarly journals Adjustable light source for low light level with nearly constant correlated color temperature

2022 ◽  
Vol 2149 (1) ◽  
pp. 012016
Author(s):  
Z F Wu ◽  
L Li ◽  
C H Dai ◽  
Y F Wang ◽  
Q T Cheng ◽  
...  
Keyword(s):  
Light Source ◽  
Spectral Distribution ◽  
Light Level ◽  
Color Temperature ◽  
Spectral Radiance ◽  
Integrating Sphere ◽  
Spectral Difference ◽  
Low Light ◽  
Light Levels ◽  
Variable Aperture

Abstract Low light level (LLL) calibration becomes more and more important since the rapid growth of remote sensing. The spectral radiance at normal higher light levels can be calibrated with good accuracy, while LLL spectral radiance cannot. If an adjustable light source can be designed at nearly constant correlated color temperature (CCT) covering several orders of magnitude, low light level spectral radiance can be obtained with the help of a photodetector. Whether or not the spectral distribution of an integrating sphere based light source is nearly constant is investigated. By adjusting the diameter of the variable aperture between the integrating sphere and tungsten lamp, the spectral radiance can be varied over 6 orders of magnitude. However, the relative spectrum in the red region increases notably when the spectral radiance is decreased to 1/100000. If the spectral radiance is decreased further, the spectral difference can be more than 300% and CCT decreases more than 250 K. By using baffles and another integrating sphere, low light level radiation source at nearly constant spectral distribution is obtained. The variation of CCT is less than 50 K over 6 orders of magnitude.

An Evaluative Study of Three Photographic Focusing Screens under Two Levels of Illumination

1980 ◽  
Vol 9 (1) ◽  
pp. 37-44
Author(s):  
John B. Bunch
Keyword(s):  
Light Level ◽  
Illumination Level ◽  
Low Light ◽  
Evaluative Study ◽  
Light Levels ◽  
High Illumination ◽  
Significant Difference ◽  
Low Illumination ◽  
Post Hoc

The purpose of this experiment was to evaluate the ability of photography students to focus a camera accurately under two levels of illumination (high/low) with three types of focusing screens (plain groundglass, split-image and microprism). The participants were required to focus each screen three times under each light level; scores were focus errors in feet. A 2 × 3 MANOVA design was used, and post hoc comparisons were made for plain vs. split-image, plain vs. microprism, and plain vs. microprism and split-image combined. There was significantly less focus error (p < .05) under the low illumination level, but no significant difference between screen types across both light levels. The screen type X light level interaction was much higher than the p .05 required in this study. Plain groundglass produced the least overall error; microprism yielded the least error under low illumination and the highest error under high illumination; and split-image was the most accurate under high illumination and the least accurate for the low light level condition.

scholarly journals Evolution of vertebrate retinal photoreception

2009 ◽  
Vol 364 (1531) ◽  
pp. 2911-2924 ◽  
Author(s):  
Trevor D. Lamb
Keyword(s):  
Ganglion Cells ◽  
Deep Ocean ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Low Light ◽  
Vertebrate Retina ◽  
Light Levels ◽  
Retinal Circuitry ◽  
Shed Light

Recent findings shed light on the steps underlying the evolution of vertebrate photoreceptors and retina. Vertebrate ciliary photoreceptors are not as wholly distinct from invertebrate rhabdomeric photoreceptors as is sometimes thought. Recent information on the phylogenies of ciliary and rhabdomeric opsins has helped in constructing the likely routes followed during evolution. Clues to the factors that led the early vertebrate retina to become invaginated can be obtained by combining recent knowledge about the origin of the pathway for dark re-isomerization of retinoids with knowledge of the inability of ciliary opsins to undergo photoreversal, along with consideration of the constraints imposed under the very low light levels in the deep ocean. Investigation of the origin of cell classes in the vertebrate retina provides support for the notion that cones, rods and bipolar cells all originated from a primordial ciliary photoreceptor, whereas ganglion cells, amacrine cells and horizontal cells all originated from rhabdomeric photoreceptors. Knowledge of the molecular differences between cones and rods, together with knowledge of the scotopic signalling pathway, provides an understanding of the evolution of rods and of the rods' retinal circuitry. Accordingly, it has been possible to propose a plausible scenario for the sequence of evolutionary steps that led to the emergence of vertebrate photoreceptors and retina.

scholarly journals Inhibition Controls Receptive Field Size, Sensitivity, and Response Polarity of Direction Selective Ganglion Cells Near the Threshold of Vision

2019 ◽  
Author(s):  
Xiaoyang Yao ◽  
Greg D. Field
Keyword(s):  
Parallel Processing ◽  
Receptive Field ◽  
Ganglion Cells ◽  
Conditional Knockout ◽  
Field Size ◽  
Low Light ◽  
Receptive Field Size ◽  
Absolute Sensitivity ◽  
Light Levels ◽  
The Absolute

AbstractInformation about motion is encoded by direction-selective retinal ganglion cells (DSGCs). These cells reliably transmit this information across a broad range of light levels, spanning moonlight to sunlight. Previous work indicates that adaptation to low light levels causes heterogeneous changes to the direction tuning of ON-OFF (oo)DSGCs and suggests that superior-preferring ON-OFF DSGCs (s-DSGCs) are biased toward detecting stimuli rather than precisely signaling direction. Using a large-scale multi-electrode array, we measured the absolute sensitivity of ooDSGCs and found that s-DSGCs are ten-fold more sensitive to dim flashes of light than other ooDSGCs. We measured their receptive field sizes and found that s-DSGCs also have larger receptive fields than other ooDSGCs, however, the size difference does not fully explain the sensitivity difference. Using a conditional knockout of gap junctions and pharmacological manipulations, we demonstrate that GABA-mediated inhibition contributes to the difference in absolute sensitivity and receptive field size at low light levels, while the connexin36-mediated gap junction coupling plays a minor role. We further show that GABA-mediated inhibition masks the OFF response of ooDSGCs under scotopic conditions, restricting their responses to increases in light. These results reveal that GABAergic inhibition controls and differentially modulates the responses of ooDSGCs under scotopic conditions.Significance StatementLight adaptation and parallel processing are two major functions of retina. Here we show that parallel processing is differentially regulated between photopic and scotopic conditions across DSGCs. This differential adaptation alters the absolute sensitivity and RF size of s-DSGCs relative to other ooDSGC types. These results point to novel mechanisms and possibly new circuit elements that shape retinal processing of motion under rod-mediated light levels.

scholarly journals Effects of Light, N and Defoliation on Biomass Allocation in Poa annua

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1783
Author(s):  
Louis John Irving ◽  
Sayuki Mori
Keyword(s):  
Biomass Allocation ◽  
Light Level ◽  
Poa Annua ◽  
Root Mass ◽  
Light Conditions ◽  
Low Light ◽  
Light Levels ◽  
Below Ground ◽  
Shoot Mass

Plants allocate biomass to above- and below-ground organs in response to environmental conditions. While the broad patterns are well-understood, the mechanisms by which plants allocate new growth remain unclear. Modeling approaches to biomass allocation broadly split into functional equilibrium type models and more mechanistically based transport resistance type models. We grew Poa annua plants in split root boxes under high and low light levels, high and low N supplies, with N supplied equally or unequally. Our data suggest that light level had the strongest effect on root mass, with N level being more important in controlling shoot mass. Allocation of growth within the root system was compatible with phloem partitioning models. The root mass fraction was affected by both light and N levels, although within light levels the changes were primarily due to changes in shoot growth, with root mass remaining relatively invariant. Under low light conditions, plants exhibited increased specific leaf area, presumably to compensate for low light levels. In a follow-up experiment, we showed that differential root growth could be suppressed by defoliation under low light conditions. Our data were more compatible with transport resistance type models.

SCUBA diver-operated low-light-level video system for use in underwater research and survey

1987 ◽  
Vol 67 (2) ◽  
pp. 299-306 ◽  
Author(s):  
G. W. Potts ◽  
J. W. Wood ◽  
J. M. Edwards
Keyword(s):  
High Resolution ◽  
Power Supply ◽  
Light Level ◽  
Natural Light ◽  
Scuba Diver ◽  
Ambient Light ◽  
Low Light ◽  
Marine Research ◽  
Light Levels ◽  
External Power

Television cameras and video equipment are well established as tools in many areas of marine research and have been reviewed by Barnes (1963), Myrberg (1973), Harris (1980), and Holme (1984, 1985). The TV camera is usually mounted on a remote sledge (Machan & Fedra, 1975; Holme & Barrett, 1977) or submersible, often with arrays of lights, and lacks the manoeuvrability that is necessary for many types of detailed survey and behavioural recording. Commercial and industrial uses also demand high-resolution equipment that is often contained in bulky underwater cases capable of operating at great depths and well below that possible by the conventional SCUBA diver. It is not unusual for the equipment to be used in conjunction with external lighting units where natural light levels are too low for the use of ambient light, and is dependent on an external power supply normally situated in the surface support vessel or within a submersible (Sisman, 1982).

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