Possible role of the central retinular cells in the ommatidia of male black flies (Diptera: Simuliidae)

1987 ◽  
Vol 65 (12) ◽  
pp. 3186-3188 ◽  
Author(s):  
Susan B. McIver ◽  
Gail E. O'Grady
Keyword(s):  
Sensory Receptor ◽  
Compound Eyes ◽  
Black Flies ◽  
Dorsal Region ◽  
Blue Range ◽  
Retinular Cells ◽  
Dioptric Apparatus ◽  
Receptor Layer ◽  
Swarm Formation

In Cnephia dacotensis, a species that mates on rocks and plants without swarm formation, the eyes of the males are separate and undivided. Each ommatidium consists of two general regions: a distal dioptric apparatus and a sensory receptor layer with eight retinular cells. Six of these cells (R1–6) are located peripherally and two centrally; R7 occurs distally and R8 basally. In males of previously studied species in which females are detected as they fly above a male swarm, the compound eyes are holoptic and divided into distinct dorsal and ventral regions. Ommatidia in the dorsal region lack the R7 cell. If in black flies R7 is a blue receptor and R8 a uv receptor, then the absence of R7 means that swarm-forming males see the females against a background that provides a sharper contrast than a background of a uv to blue range. This would sharpen the visibility of the dark female against the background skylight, enabling the male to perceive her more swiftly.

Fine structure of the compound eye of the black fly Simulium vittatum (Diptera: Simuliidae)

1987 ◽  
Vol 65 (6) ◽  
pp. 1454-1469 ◽  
Author(s):  
Gail E. O'Grady ◽  
Susan B. McIver
Keyword(s):  
Fine Structure ◽  
Compound Eye ◽  
Sensory Receptor ◽  
Dorsal Region ◽  
Male And Female ◽  
Simulium Vittatum ◽  
Transmission Electron ◽  
Accessory Pigment ◽  
Open Rhabdom ◽  
Retinular Cells

The fine structure of the ommatidia in light- and dark-adapted eyes of male and female Simulium vittatum Zetterstedt was investigated using scanning and transmission electron microscopy. The male eye is divided into distinct dorsal and ventral regions. The facets in the dorsal region are approximately two times larger than those in the ventral one, which are similar in size to the ones in the female eye. All ommatidia of S. vittatum examined consist of two general regions: a distal dioptric apparatus with bordering primary and accessory pigment and Semper cells, and a sensory receptor layer. Each ommatidium in the female eye and ventral eye of the male has eight retinular cells (R cells): six peripheral (R1–6) and two central (R7, R8). R7 occurs distally and R8 basally. Strikingly, the ommatidia in the dorsal eye of the male lack the R7 cell. In all ommatidia, rhabdomeres on the inner surface of the peripheral R cells are separate throughout their length, creating an open rhabdom. A greater diameter of corneal facets, elongated peripheral R cells, and perhaps the lack of the R7 cell are specializations of the dorsal region of the eye that help the male to detect small, rapidly moving females against the skylight as they fly above the swarm of males. Differences observed between light- and dark-adapted eyes of male and female S. vittatum were the same and were associated with the internal components of the peripheral R cells.

Interactions between compound and normal eye projections in dually innervated tectum: a study of optic nerve regeneration in Xenopus

Development ◽  
1981 ◽  
Vol 66 (1) ◽  
pp. 159-174
Author(s):  
Charles Straznicky ◽  
David Tay
Keyword(s):  
Optic Nerve ◽  
Nerve Regeneration ◽  
Compound Eye ◽  
Compound Eyes ◽  
Lateral Region ◽  
Optic Nerve Regeneration ◽  
Xenopus Embryos ◽  
Retinotectal Projections ◽  
Two Populations

Right compound eyes were formed in Xenopus embryos at tailbud stages by the fusion of two nasal (NN), two temporal (TT) or two ventral (VV) halves. The left eye was kept intact. Two to four weeks after metamorphosis the optic nerve from the intact eye was severed to induce bilateral optic nerve regeneration. The contralateral retinotectal projections from the compound eye and the induced ipsilateral projections from the intact eye to the same (dually innervated) tectum were studied by [3H]proline autoradiography and visuotectal mapping from 3 to 6 months after the postmetamorphic surgery. The results showed that the NN, TT and VV projections, in the presence of optic fibres from the intact eye failed to spread across the whole extent of the dually innervated tectum. Unexpectedly the bulk of the regenerating projection from the intact eye was confined to the previously uninnervated parts of the dually innervated tecta, the caudomedial region in TT, the rostrolateral region in NN and the lateral region in VV eye animals. The partial segregation of the two populations of optic fibres in the dually innervated tectum has been taken as a further indication of the role of fibre-fibre and fibre-tectum interactions in retinotectal map formation.

scholarly journals Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology

2020 ◽  
Vol 6 (49) ◽  
pp. eabc6721
Author(s):  
John R. Paterson ◽  
Gregory D. Edgecombe ◽  
Diego C. García-Bellido
Keyword(s):  
Crucial Role ◽  
Compound Eye ◽  
Marine Ecosystems ◽  
Growth Mode ◽  
Compound Eyes ◽  
Suspension Feeding ◽  
Ecological Diversity ◽  
Crown Group ◽  
Developmental Growth

Radiodonts are nektonic stem-group euarthropods that played various trophic roles in Paleozoic marine ecosystems, but information on their vision is limited. Optical details exist only in one species from the Cambrian Emu Bay Shale of Australia, here assigned to Anomalocaris aff. canadensis. We identify another type of radiodont compound eye from this deposit, belonging to ‘Anomalocaris’ briggsi. This ≤4-cm sessile eye has >13,000 lenses and a dorsally oriented acute zone. In both taxa, lenses were added marginally and increased in size and number throughout development, as in many crown-group euarthropods. Both species’ eyes conform to their inferred lifestyles: The macrophagous predator A. aff. canadensis has acute stalked eyes (>24,000 lenses each) adapted for hunting in well-lit waters, whereas the suspension-feeding ‘A.’ briggsi could detect plankton in dim down-welling light. Radiodont eyes further demonstrate the group’s anatomical and ecological diversity and reinforce the crucial role of vision in early animal ecosystems.

scholarly journals Postnatal Development of the Subcellular Structures and Purinergic Signaling of Deiters’ Cells along the Tonotopic Axis of the Cochlea

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1266 ◽  
Author(s):  
Eszter Berekméri ◽  
Ádám Fekete ◽  
László Köles ◽  
Tibor Zelles
Keyword(s):  
Purinergic Signaling ◽  
Organ Of Corti ◽  
Supporting Cell ◽  
Sensory Receptor ◽  
Hearing Impairments ◽  
Supporting Cells ◽  
Sensory Receptor Cells ◽  
Single Cell Electroporation ◽  
First Time

Exploring the development of the hearing organ helps in the understanding of hearing and hearing impairments and it promotes the development of the regenerative approaches-based therapeutic efforts. The role of supporting cells in the development of the organ of Corti is much less elucidated than that of the cochlear sensory receptor cells. The use of our recently published method of single-cell electroporation loading of a fluorescent Ca2+ probe in the mouse hemicochlea preparation provided an appropriate means to investigate the Deiters’ cells at the subcellular level in two different cochlear turns (apical, middle). Deiters’ cell’s soma and process elongated, and the process became slimmer by maturation without tonotopic preference. The tonotopically heterogeneous spontaneous Ca2+ activity less frequently occurred by maturation and implied subcellular difference. The exogenous ATP- and UTP-evoked Ca2+ responses were maturation-dependent and showed P2Y receptor dominance in the apical turn. By monitoring the basic structural dimensions of this supporting cell type as well as its spontaneous and evoked purinergic Ca2+ signaling in the hemicochlea preparation in different stages in the critical postnatal P5-25 developmental period for the first time, we showed that the soma and the phalangeal process of the Deiters’ cells go through age- and tonotopy-dependent changes in the morphometric parameters and purinergic signaling.

Alternatives to superposition images in clear-zone compound eyes

1971 ◽  
Vol 179 (1055) ◽  
pp. 97-124 ◽  
Keyword(s):  
Scattered Light ◽  
Retinula Cell ◽  
Compound Eyes ◽  
Clear Zone ◽  
Light Effect ◽  
Angular Sensitivity ◽  
Dim Light ◽  
Optical Pathway ◽  
Receptor Layer

The clear zone between the cones and the receptor layer in dark -adapted eyes of insects that are active in dim light has formerly been explained as a space to allow formation of a superposition image. Although erect images have been seen in Ephestia (Lepidoptera) and Hydrophilus (Coleoptera), new experiments show that they are accompanied by scattered light and that the angular sensitivity of individual receptors must be wide in the dark-adapted state. Alternatives to the superposition theory are examined, and it is concluded that in eyes with crystalline cones the clear zone (in general, in the numerous shapes and sizes of eyes of nocturnally active insects) enables light entering by many facets to sum upon individual receptors on the far side of the clear zone. In addition to the scattered light effect, light is carried across the clear zone in crystalline tracts or retinula cell columns, which provide a separate optical pathway for each ommatidium also in the light-adapted state.

scholarly journals Role of human premotor dorsal region in learning a conditional visuomotor task

2017 ◽  
Vol 117 (1) ◽  
pp. 445-456 ◽  
Author(s):  
Pranav J. Parikh ◽  
Marco Santello
Keyword(s):  
Motor Response ◽  
Response Selection ◽  
Center Of Mass ◽  
Selection Response ◽  
Response Monitoring ◽  
Dorsal Region ◽  
Visuomotor Task ◽  
Conditional Learning ◽  
Stimulus Identification

Conditional learning is an important component of our everyday activities (e.g., handling a phone or sorting work files) and requires identification of the arbitrary stimulus, accurate selection of the motor response, monitoring of the response, and storing in memory of the stimulus-response association for future recall. Learning this type of conditional visuomotor task appears to engage the premotor dorsal region (PMd). However, the extent to which PMd might be involved in specific or all processes of conditional learning is not well understood. Using transcranial magnetic stimulation (TMS), we demonstrate the role of human PMd in specific stages of learning of a novel conditional visuomotor task that required subjects to identify object center of mass using a color cue and to apply appropriate torque on the object at lift onset to minimize tilt. TMS over PMd, but not vertex, increased error in torque exerted on the object during the learning trials. Analyses of digit position and forces further revealed that the slowing in conditional visuomotor learning resulted from impaired monitoring of the object orientation during lift, rather than stimulus identification, thus compromising the ability to accurately reduce performance error across trials. Importantly, TMS over PMd did not alter production of torque based on the recall of learned color-torque associations. We conclude that the role of PMd for conditional learning is highly sensitive to the stage of learning visuomotor associations. NEW & NOTEWORTHY Conditional learning involves stimulus identification, motor response selection, response monitoring, memory encoding, and recall of the learned association. Premotor dorsal (PMd) has been implicated for conditional learning. However, the extent to which PMd might be involved in specific or all stages of conditional learning is not well understood. The novel finding of our study is that PMd appears to be involved with monitoring motor responses, a sensorimotor integration stage essential for conditional learning.

Essential fatty acid deficiency impairs the responsiveness of renal pelvic sensory receptors

1995 ◽  
Vol 268 (1) ◽  
pp. R164-R170 ◽  
Author(s):  
U. C. Kopp ◽  
D. M. Farley ◽  
L. A. Smith ◽  
H. R. Knapp
Keyword(s):  
Fatty Acid ◽  
Essential Fatty Acid ◽  
Receptor Activation ◽  
Sensory Receptor ◽  
Standard Diet ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Renal Nerve Activity ◽  
Fatty Acid Deficiency

The role of prostaglandins in renal sensory receptor activation was examined in rats fed an essential fatty acid-deficient (EFAD) diet to cause tissue arachidonate depletion. Littermates fed a standard diet were used as controls. In anesthetized rats, the increases in afferent renal nerve activity due to increasing ureteral pressure 2.5, 5, 7.5, 10, 12.5, and 15 mmHg were significantly reduced by the EFAD diet (P < 0.02): 3 +/- 5, 3 +/- 5, 11 +/- 5, 9 +/- 5, 19 +/- 3, and 17 +/- 5%, respectively, in EFAD rats and 23 +/- 11, 36 +/- 15, 50 +/- 15, 52 +/- 8, 72 +/- 17, and 90 +/- 19%, respectively, in control rats. In EFAD rats, addition of prostaglandin E2 (PGE2) to the renal pelvic perfusate restored the afferent renal nerve activity response to increased ureteral pressure toward that in control rats. PGE2 had no effect in control rats. Also the afferent renal nerve activity responses to renal pelvic perfusion with bradykinin at 4, 20, 100, and 500 micrograms/ml were significantly suppressed by the EFAD diet (P < 0.01): 13 +/- 15, 5 +/- 7, 60 +/- 19, and 63 +/- 20%, respectively, in EFAD rats and 122 +/- 23, 142 +/- 31, 172 +/- 19, and 190 +/- 39%, respectively, in control rats. These results demonstrate an important role for arachidonate metabolites, particularly PGE2, in renal sensory receptor activation. Together with our previous studies showing that indomethacin blocks the afferent renal nerve activity responses to increased ureteral pressure or bradykinin, the present studies provide strong evidence for an essential role of prostaglandins in renal sensory receptor activation.

scholarly journals Localization of the Violet and Yellow Receptor Cells in the Crayfish Retinula

1973 ◽  
Vol 62 (4) ◽  
pp. 355-374 ◽  
Author(s):  
Eisuke Eguchi ◽  
Talbot H. Waterman ◽  
Jiro Akiyama
Keyword(s):  
Light Adaptation ◽  
Selective Adaptation ◽  
Compound Eyes ◽  
Intracellular Recordings ◽  
Intercellular Coupling ◽  
Retinular Cell ◽  
Particle Distributions ◽  
Wavelength Sensitivity ◽  
Retinal Distribution ◽  
Retinular Cells

Cellular identification of color receptors in crayfish compound eyes has been made by selective adaptation at 450 nm and 570 nm, wavelengths near the λmax's of the two retinular cell classes previously demonstrated. By utilizing earlier evidence, the concentration of lysosome-related bodies (LRB) was used to measure relative light adaptation and thus wavelength sensitivity in 665 retinular cells from six eyes. The observed particle distributions demonstrate the following. Both violet and yellow receptors occur ordinarily in each retinula. Of the seven regular retinular cells two (R3 and R4 using Eguchi's numbering [1965]) have mean sensitivities significantly greater to violet and less to yellow than the other five. The latter apparently comprise "pure" yellow receptors (R1 and R7) and mixed yellow and violet receptors (R2, R5, and R6). Explanations of such ambiguity requiring two visual pigments in single retinular cells or intercellular coupling of adjacent neuroreceptors are apparently precluded by previous evidence. Present data imply alternatively some positional variability in the violet pair's location in individual retinulas. Thus R3 and R4 are predominantly the violet receptors but in some retinulas R2 and R3 or R4 and R5 (or rarely some other cell pairs) may be. The retinal distribution of such variations has yet to be determined. In agreement with intracellular recordings the blue and yellow cells here identified belong to both the vertical and horizontal e-vector sensitive channels.

The role of sex chromosomes in black fly evolution

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 538-542 ◽  
Author(s):  
R. M. Feraday ◽  
K. G. Leonhardt ◽  
C. L. Brockhouse
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Chromosome Rearrangements ◽  
Black Flies ◽  
Black Fly ◽  
Adaptive Process ◽  
Y Chromosomes

Sex chromosomes have been repeatedly implicated in the process of speciation of black flies and other nemotocerans. Arguments are presented here against the case that frequent differences between species in their sex chromosomes are based on (i) different average rates of differentiation of sex-linked and autosomal loci or (ii) the fact that the X and Y chromosomes are less numerous than autosomal chromosomes and so are more subject to the effects of drift and the random fixation of chromosome rearrangements. The argument is made that speciation in black flies and many other groups is an adaptive process and that differentiated sex-chromosome systems play a role in this process.Key words: black flies, sex chromosomes, speciation, evolution.

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