Postembryonic development of the visual system of the locust, Schistocerca gregaria

Development ◽  
1978 ◽  
Vol 45 (1) ◽  
pp. 55-83
Author(s):  
Hilary Anderson
Keyword(s):  
Visual System ◽  
Anterior Margin ◽  
Optic Lobe ◽  
Schistocerca Gregaria ◽  
Photoreceptor Cells ◽  
Postembryonic Development ◽  
Stem Cell Population ◽  
Experimental Conditions ◽  
Plausible Mechanism ◽  
Parallel Pattern

The visual system of the locust, Schistocerca gregaria, has a highly ordered and predictable arrangement of neurons. The retina and the outermost layer, or lamina, of the optic lobe are each composed of repeating units, ommatidia and cartridges respectively. Each ommatidium has eight photoreceptor cells, which send axons directly to a group of five neurons in the lamina to form the cartridge. The importance, for the development of this precise pattern, of the mode of growth of the two arrays and of interactions between them was investigated. The spatial and temporal sequences of cell proliferation, differentiation and death in the developing retina and optic lobe were examined quantitatively under normal and experimental conditions. The retina grows from its anterior margin by addition of new ommatidia formed from recruited epidermal cells. The lamina also grows by addition of new neurons to its anterior margin, but these neurons are derived from a stem cell population. The parallel pattern of growth of the retina and lamina may be important for the formation of neuronal connexions between them. The retina grows and differentiates even when deprived of the underlying lamina. In laminae deprived of the ingrowth of new axons from the retina, the production of new neurons is also autonomous, but these neurons do not differentiate, but degenerate. A limited amount of cell death occurs in the laminae of control insects. These two observations suggest that a plausible mechanism for coordinating the sizes of the two arrays during normal development might be production of lamina neurons in excess of requirements and death of those remaining non-innervated.

scholarly journals The visual system of the genetically tractable crustacean Parhyale hawaiensis: diversification of eyes and visual circuits associated with low-resolution vision

2019 ◽  
Author(s):  
Ana Patricia Ramos ◽  
Ola Gustafsson ◽  
Nicolas Labert ◽  
Iris Salecker ◽  
Dan-Eric Nilsson ◽  
...  
Keyword(s):  
Light Intensity ◽  
Visual System ◽  
Photoreceptor Cell ◽  
Optic Lobe ◽  
Photoreceptor Cells ◽  
Single Species ◽  
Low Resolution ◽  
Parhyale Hawaiensis ◽  
Visual Tasks ◽  
Significant Divergence

AbstractBackgroundArthropod eyes have diversified during evolution to serve multiple needs, such as finding mates, hunting prey, and navigating in complex surroundings under varying light conditions. This diversity is reflected in the optical apparatus, photoreceptors and neural circuits that underpin vision. While this diversity has been extensively documented, our ability to genetically manipulate the visual system to investigate its function is largely limited to a single species, the fruitfly Drosophila melanogaster. Here, we describe the visual system of Parhyale hawaiensis, an amphipod crustacean for which we have established tailored genetic tools.ResultsAdult Parhyale have apposition-type compound eyes made up of ∼50 ommatidia. Each ommatidium contains four photoreceptor cells with large rhabdomeres (R1-4), expected to be sensitive to the polarisation of light, and one photoreceptor cell with a smaller rhabdomere (R5). The two types of photoreceptors express different opsins, belonging to families with distinct wavelength sensitivities. Using the cis.-regulatory regions of opsin genes, we established transgenic reporters expressed in each photoreceptor cell type. Based on these reporters, we show that R1-4 and R5 photoreceptors extend axons to the first optic lobe neuropil, revealing striking differences compared with the photoreceptor projections found in related crustaceans and insects. Investigating visual function, we show that Parhyale has a positive phototactic response and is capable of adapting its eyes to different levels of light intensity.ConclusionsWe propose that the visual system of Parhyale serves low-resolution visual tasks, such as orientation and navigation, based on broad gradients of light intensity and polarisation. Optic lobe structure and photoreceptor projections point to significant divergence from the conserved visual circuits found in other malacostracan crustaceans and insects, which could be associated with a shift to low-resolution vision. Our study provides the foundation for research in the visual system of this genetically tractable species.

Postembryonic development of the visual system of the locust, Schistocerca gregaria

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 147-170
Author(s):  
Hilary Anderson
Keyword(s):  
Visual System ◽  
Temporal Relationship ◽  
Compound Eye ◽  
Normal Development ◽  
Schistocerca Gregaria ◽  
Postembryonic Development ◽  
Inductive Interaction ◽  
Topographical Mapping

In the compound eye of the locust, Schistocerca gregaria, neurons from the retina project to the lamina in a precise topographical mapping. The formation of this projection was investigated in grafting experiments which altered the spatial or temporal relationship between the retina and the lamina. The results show that retina axons tend to grow along the paths of adjacent axons, with no indication of specificity for their normal termination sites. It is suggested that the orderly sequence of retina differentiation during normal development plays a major role in imposing pattern both upon the developing projection and, through some form of inductive interaction between retina and lamina neurons, upon the lamina.

scholarly journals sine oculis is a homeobox gene required for Drosophila visual system development.

Genetics ◽  
1994 ◽  
Vol 138 (4) ◽  
pp. 1137-1150 ◽  
Author(s):  
M A Serikaku ◽  
J E O'Tousa
Keyword(s):  
Embryonic Development ◽  
Visual System ◽  
Gene Product ◽  
Optic Lobe ◽  
System Development ◽  
Photoreceptor Cells ◽  
P Element ◽  
Sine Oculis ◽  
Visual System Development ◽  
Bolwig's Organ

Abstract The somda (sine oculis-medusa) mutant is the result of a P element insertion at position 43C on the second chromosome. somda causes aberrant development of the larval photoreceptor (Bolwig's) organ and the optic lobe primordium in the embryo. Later in development, adult photoreceptors fail to project axons into the optic ganglion. Consequently optic lobe development is aborted and photoreceptor cells show age-dependent retinal degeneration. The so gene was isolated and characterized. The gene encodes a homeodomain protein expressed in the optic lobe primordium and Bolwig's organ of embryos, in the developing adult visual system of larvae, and in photoreceptor cells and optic lobes of adults. In addition, the SO product is found at invagination sites during embryonic development: at the stomadeal invagination, the cephalic furrow, and at segmental boundaries. The mutant somda allele causes severe reduction of SO embryonic expression but maintains adult visual system expression. Ubiquitous expression of the SO gene product in 4-8-hr embryos rescues all somda mutant abnormalities, including the adult phenotypes. Thus, all deficits in adult visual system development and function results from failure to properly express the so gene during embryonic development. This analysis shows that the homeodomain containing SO gene product is involved in the specification of the larval and adult visual system development during embryogenesis.

Contralateral coordination and retargeting of limb movements during scratching in the locust

1998 ◽  
Vol 201 (13) ◽  
pp. 2021-2032 ◽  
Author(s):  
T Matheson
Keyword(s):  
Nerve Cord ◽  
Tactile Stimulation ◽  
Schistocerca Gregaria ◽  
Limb Movements ◽  
Single Cycle ◽  
Experimental Conditions ◽  
The Subject ◽  
The Common ◽  
Peripheral Sensory ◽  
Stimulus Site

Locusts, Schistocerca gregaria, in common with many limbed vertebrates, can make directed scratching movements in response to tactile stimulation. For instance, stimulation of different sites on a wing elicits different movements that are accurately targeted so that the hindleg tarsus passes across the stimulus site. I have analysed these limb movements to define the ability of a locust to target stimulus sites correctly under a range of experimental conditions. In particular, I describe aspects of the behaviour that reveal possible neuronal pathways underlying the responses. These neuronal pathways will be the subject of further physiological analyses. Limb targeting during scratching is continuously graded in form; different patterns of movement are not separated by sharp transitions. The computation of limb trajectory takes into account the starting posture of the hindleg, so that different trajectories can be used to reach a common stimulus site from different starting postures. Moreover, the trajectories of the two hindlegs moving simultaneously from different starting postures in response to a single stimulus can be different, so that their tarsi converge onto the common stimulus site. Different trajectories can be used to reach a common stimulus site from the same start posture. Targeting information from a forewing is passed not only down the nerve cord to the ipsilateral hindleg but also across the nerve cord, so that the contralateral hindleg can also make directed movements. This contralateral transmission does not rely on peripheral sensory feedback. When the stimulus site moves during a rhythmical scratch, the targeting of subsequent cycles reflects this change. Both ipsilateral and contralateral hindlegs can retarget their movements. The trajectory of a single cycle of scratching directed towards a particular stimulus site can be modified after it has begun, so that the tarsus is redirected towards a new stimulus site.

Plasticity in the Visual System Is Correlated With a Change in Lifestyle of Solitarious and Gregarious Locusts

2004 ◽  
Vol 91 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Thomas Matheson ◽  
Stephen M. Rogers ◽  
Holger G. Krapp
Keyword(s):  
Visual System ◽  
Flight Control ◽  
Schistocerca Gregaria ◽  
Movement Detector ◽  
Time To Collision ◽  
Angular Extent ◽  
Behavioral Phase ◽  
Contralateral Movement ◽  
Gregarious Locusts ◽  
And Behavior

We demonstrate pronounced differences in the visual system of a polyphenic locust species that can change reversibly between two forms (phases), which vary in morphology and behavior. At low population densities, individuals of Schistocerca gregaria develop into the solitarious phase, are cryptic, and tend to avoid other locusts. At high densities, individuals develop instead into the swarm-forming gregarious phase. We analyzed in both phases the responses of an identified visual interneuron, the descending contralateral movement detector (DCMD), which responds to approaching objects. We demonstrate that habituation of DCMD is fivefold stronger in solitarious locusts. In both phases, the mean time of peak firing relative to the time to collision nevertheless occurs with a similar characteristic delay after an approaching object reaches a particular angular extent on the retina. Variation in the time of peak firing is greater in solitarious locusts, which have lower firing rates. Threshold angle and delay are therefore conserved despite changes in habituation or behavioral phase state. The different rates of habituation should contribute to different predator escape strategies or flight control for locusts living either in a swarm or as isolated individuals. For example, increased variability in the habituated responses of solitarious locusts should render their escape behaviors less predictable. Relative resistance to habituation in gregarious locusts should permit the continued responsiveness required to avoid colliding with other locusts in a swarm. These results will permit us to analyze neuronal plasticity in a model system with a well-defined and controllable behavioral context.

scholarly journals Variation and structure of the eyes in the desert locust, Schistocerca gregaria (Forskål)

1947 ◽  
Vol 134 (875) ◽  
pp. 245-272 ◽  
Keyword(s):  
Schistocerca Gregaria ◽  
Postembryonic Development ◽  
Compound Eyes ◽  
Brown Pigment ◽  
Desert Locust ◽  
Direct Sunlight ◽  
The Third ◽  
Third Stage ◽  
Visual Impact ◽  
The One

The compound eyes of the solitaria phase individuals of the desert locust, Schistocerca gregaria (Forskål), are vertically striped with mostly 6 and 7, rarely 5 and 8, dark brown stripes, and a number of cream-coloured interstripes. In phase gregaria the interstripes, which are more or less invaded by brown pigment, are partially or wholely masked, the eye in the latter case presenting an almost uniformly dark brown appearance. The postembryonic development of the striped eyes, is described stage by stage. There is no stripe at the time of hatching. In the 6-striped eye one stripe is developed in the first-stage hopper and, subsequently a stripe is added at each of the five moults. In the 7-striped eye the one-moult-one stripe relationship holds good in most stages, but the extra seventh stripe is produced in two ways: (i) By the addition of two stripes at the second moult (i. e. the third-stage hopper has four stripes instead of three); and (ii) by the interposition of an extra-moult, usually in the third stage and rarely in the fourth, during which a new stripe is added (stripe-positive extra-moult). But extra-moulting does not necessarily lead to the addition of a stripe; stripe-neutral extra-moults are not infrequent. The development of the dorsal spot and the subdorsal streak are described. The mechanism of growth and the homology and nomenclature of the stripes and interstripes are discussed. The structure of the compound eyes and the pigmentary basis of stripe formation are described, and their effects on vision in solitaria and gregaria individuals discussed. Vision is discussed on the basis of ommatidial structure and pigmentation. In gregaria eyes a perfect apposition image is formed, the image being sharply defined. An ‘anti-halation’ device, produced by the post-retinular layer of pigment, is present. The eye is suited for diurnal vision, and strong direct sunlight is not avoided. In solitaria eyes the image is of the apposition type in its mode of formation but of the superposition type in effect; it has been termed a ‘pseudo-superposition’ image, and is more diffuse but brighter than in gregaria eyes. The ‘anti-halation’ device is weak and ineffective. The eye is suited for vision in subdued light and perceives movements rather than sharp images. Solitaria individuals, especially hoppers, avoid strong, direct sunlight. The effects of these differences in vision on the behaviour of gregaria - and solitaria -phase individuals are as follows: the former, owing to mutual visual impact induced by the formation of sharp images, tend to be gregarious; and further, owing to the presence of light-absorbing mechanisms, they do not avoid strong sunlight; the latter, on the other hand, owing to the want or comparative ineffectiveness of the above-mentioned features, neither tend to congregate nor to go out boldly into the bright open.

scholarly journals Neoteny in visual system development of the spotted unicornfish, Naso brevirostris (Acanthuridae)

2019 ◽  
Author(s):  
Valerio Tettamanti ◽  
Fanny de Busserolles ◽  
David Lecchini ◽  
Justin Marshall ◽  
Fabio Cortesi
Keyword(s):  
Visual System ◽  
System Development ◽  
Feeding Habits ◽  
Quantitative Difference ◽  
Photoreceptor Cells ◽  
Reef Fishes ◽  
Ontogenetic Changes ◽  
Cone Opsin ◽  
Opsin Genes ◽  
Visual System Development

AbstractOntogenetic changes of the visual system are often correlated to shifts in habitat and feeding behaviour of animals. Coral reef fishes begin their lives in the pelagic zone and then migrate to the reef. This transition of habitat frequently involves a change in diet and light environment as well as major morphological modifications. The spotted unicornfish, Naso brevirostris, is known to shift diet from zooplankton to algae and back to zooplankton when transitioning from larval to juvenile and then to adult stages. Concurrently, N. brevirostris also moves from an open pelagic to a coral-associated habitat before migrating up in the water column when reaching adulthood. Using retinal mapping techniques, we discovered that the distribution and density of ganglion and photoreceptor cells in N. brevirostris do not change with the habitat or the feeding habits of each developmental stage. Instead, fishes showed a neotenic development with a slight change from larval to juvenile stages and not many modifications thereafter. Visual gene expression based on RNA sequencing mirrored this pattern; independent of stage, fishes mainly expressed three cone opsin genes (SWS2B, RH2B, RH2A), with a quantitative difference in the expression of the green opsin genes (RH2A and RH2B) when transitioning from larvae to juveniles. Hence, contrary to the ontogenetic changes found in many animals, the visual system is fixed early on in N. brevirostris development calling for a thorough analysis of visual system development of the reef fish community.

SIMULATION OF THE RETINA: A TOOL FOR VISUAL PROSTHESES

2010 ◽  
Vol 10 (04) ◽  
pp. 513-529
Author(s):  
BARTHÉLÉMY DURETTE ◽  
JEANNY HÉRAULT ◽  
DAVID ALLEYSSON
Keyword(s):  
Visual System ◽  
Visual Information ◽  
Vision System ◽  
Local Level ◽  
Photoreceptor Cells ◽  
Simulation Software ◽  
Natural Scenes ◽  
Temporal Properties ◽  
Spatio Temporal ◽  
High Level

To extract high-level information from natural scenes, the visual system has to cope with a wide variety of ambient lights, reflection properties of objects, spatio-temporal contexts, and geometrical complexity. By pre-processing the visual information, the retina plays a key role in the functioning of the whole visual system. It is crucial to reproduce such a pre-processing in artificial devices aiming at replacing or substituting the damaged vision system by artificial means. In this paper, we present a biologically plausible model of the retina at the cell level and its implementation as a real-time retinal simulation software. It features the non-uniform sampling of the visual information by the photoreceptor cells, the non-separable spatio-temporal properties of the retina, the subsequent generation of the Parvocellular and Magnocellular pathways, and the non-linear equalization of luminance and contrast at the local level. For each of these aspects, a description of the model is provided and illustrated. Their respective interest for the replacement or substitution of vision is discussed.

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