The spatial integration of signals in the retina and lamina of the fly compound eye under different conditions of luminance

Dubs, Andreas

doi:10.1007/bf00612703

Cited by 70 publications

(75 citation statements)

References 57 publications

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“…Both experimental and theoretical impulse responses 9 get faster in a similar way when the background light intensity (or SNR) is increased; 9 get more biphasic with increased intensity (SNR), with similar time courses and similar ratios between on-and off-transients; 9 show larger off-transients for wide-field stimulation than for point-source stimulation, both in a quantitatively similar way; 9 show just a small change in the half-width of the spatial receptive field (see Dubs 1982), although there is lateral inhibition for higher intensities (SNRs); see Fig. 5 b and d.…”

Section: Discussionmentioning

confidence: 83%

Theoretical predictions of spatiotemporal receptive fields of fly LMCs, and experimental validation

1992

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1. A theory is presented that utilizes the structure of natural images, and how they change in time, to produce spatiotemporal filters that maximize information flow through a noisy channel of limited dynamic range. For low signal-to-noise ratios (SNRs) the filter has low-pass, and for high SNRs band-pass characteristics, both in space and time.2. Theoretical impulse responses are compared to measurements in Large Monopolar Cells (LMCs) in the fly (Calliphora vicina) brain. Two different spatial stimuli (point source and wide field) were given at background intensities over a 5.5 log unit wide range. Theory and experiment correspond well, and they share the following properties: impulse responses get much faster and more biphasic with increasing background intensity (SNR); they show larger off-transients for wide field stimuli than for point sources; the half-width of the spatial receptive field Changes only slightly with increased intensity, and lateral inhibition increases; contrast efficiency increases with intensity.

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Section: Discussionmentioning

confidence: 83%

Theoretical predictions of spatiotemporal receptive fields of fly LMCs, and experimental validation

1992

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“…4b). These 2 simple operations render the system more robust to changes in illumination (Dubs 1982). At the level of the Medulla we find the first visual motion sensitive neurons (Borst & Egelhaaf 1993;Douglass & Strausfeld 2003).…”

Section: Course and Altitude Controlmentioning

confidence: 73%

Humanitarian Demining Using an Insect Based Chemical Unmanned Aerial Vehicle

Bermúdez¹

2008

Humanitarian Demining

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“…A more informative indicator of the resolution is the modulation transfer function (MTF) of the eye, which is the Fourier transform of the angular-sensitivity function (Dubs 1982;Warrant and McIntyre 1990). The MTF takes account of the entire shape of the angular-sensitivity function (not just its half-width AQ), an important consideration in arthropod eyes of low F-number in which aberrations and light spread give rise to an angular-sensitivity function with large off-axis flanks (Warrant and McIntyre ).…”

Section: The Tapetal Sheath Designmentioning

confidence: 99%

Strategies for retinal design in arthropod eyes of low F-number

Warrant

McIntyre

1991

J Comp Physiol A

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Summary. The superposition eyes and simple eyes of many arthropods have apertures (A) with a diameter bigger than, or about the same size as, the focal length of the eye (f). That is, these eyes have low F-numbers (f/A). Many of the light rays focussed onto a photoreceptor will not be trapped by total internal reflection in the photoreceptor and will therefore pass through and be absorbed in photoreceptors other than that for which the light was intended. This spread of light in the retina leads to a broadening of the angular-sensitivity function and a consequent degrading of the image at the retinal level. A number of solutions to this problem are found in nature, with the most effective that of isolating the photoreceptors with a sheath of either light-absorbing pigment or reflecting tapetum. A ray-tracing model was used to assess the relative merits of the tapetal and pigment sheath designs in low F-number superposition eyes, and also to investigate the effect of changing the refractive index and absorption coefficient of the rhabdom. Which sheathing solution is best depends on the quality of the image on the retina, on the spacing of the rhabdoms in the retina and on the intensity of light normally experienced by the eye. In a retina with closely packed rhabdoms, the model predicts full sheathing to be the optimal solution if the image is well-focussed, partial sheathing if poorly focussed and no sheathing if moderately well-focussed. In a retina with rhabdoms spaced apart and a well-focussed image, the model predicts partial sheathing to be optimal. A pigment sheath is predicted to be useful in eyes which experience bright light and have no need for high sensitivity. A tapetal sheath is predicted to be useful at any intensity. A survey of arthropod eyes with low F-number supports the predictions of the model.

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The spatial integration of signals in the retina and lamina of the fly compound eye under different conditions of luminance

Cited by 70 publications

References 57 publications

Theoretical predictions of spatiotemporal receptive fields of fly LMCs, and experimental validation

Theoretical predictions of spatiotemporal receptive fields of fly LMCs, and experimental validation

Humanitarian Demining Using an Insect Based Chemical Unmanned Aerial Vehicle

Strategies for retinal design in arthropod eyes of low F-number

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