scholarly journals What causes edge fixation in walking flies?

1990 ◽  
Vol 149 (1) ◽  
pp. 281-292 ◽  
Author(s):  
D. Osorio ◽  
M. V. Srinivasan ◽  
R. B. Pinter
Keyword(s):  
Visual Field ◽  
Lateral Inhibition ◽  
Lucilia Cuprina ◽  
Dark Side ◽  
Dark Line ◽  
Dark Region ◽  
Dark Background ◽  
Mach Band ◽  
Eye Region

The orientation of freely walking flies (female Lucilia cuprina) to lines and stripes in a circular arena is described. The following observations were made. 1. The flies walked straight towards a dark line using the frontal eye region, but a pale line on a dark background was only weakly attractive. 2. In bright conditions flies walked in a curved line towards a black-white edge, the path being convex towards the dark side of the border. The curves indicated that the flies were heading for a point about 5–10 degrees to the dark side of the edge. 3. In dim conditions the edge of a dark region was not especially attractive and flies headed towards any point in the dark area. These observations can be accounted for by assuming that the fly walks towards the darkest region in its visual field (scototaxis). In bright conditions the edges of a dark region become more attractive than its centre. This change could be explained if lateral inhibition creates a ‘Mach-band’ effect, making the edges appear darker than the centre. Thus, fixation behaviour in walking Lucilia females seems to be a simple taxis.

scholarly journals Mach Band Type Lateral Inhibition in Different Sense Organs

1967 ◽  
Vol 50 (3) ◽  
pp. 519-532 ◽  
Author(s):  
Georg von Békésy
Keyword(s):  
Lateral Inhibition ◽  
Geometrical Model ◽  
Sense Organs ◽  
Sensation Magnitude ◽  
Visual Phenomenon ◽  
Mach Bands ◽  
Band Type ◽  
Mach Band

Experiments were done on the skin with shearing forces, vibrations, and heat stimuli and on the tongue with taste stimuli to show that the well known Mach bands are not exclusively a visual phenomenon. On the contrary, it is not difficult to produce areas of a decreased sensation magnitude corresponding to the dark Mach bands in vision. It is shown on a geometrical model of nervous interaction that the appearance of Mach bands for certain patterns of stimulus distribution is correlated with nervous inhibition surrounding the area of sensation. This corroborates the earlier finding that surrounding every area transmitting sensation there is an area simultaneously transmitting inhibition.

Neuronal basis of a sensory analyser, the acridid movement detector system. III. Control of response amplitude by tonic lateral inhibition

1976 ◽  
Vol 65 (3) ◽  
pp. 617-625
Author(s):  
C. H. Fraser Rowell ◽  
M. O'Shea
Keyword(s):  
Visual Field ◽  
Lateral Inhibition ◽  
Optic Lobe ◽  
Inhibitory Effect ◽  
Test Area ◽  
Detector System ◽  
Movement Detector ◽  
Field Change ◽  
Surrounding Area ◽  
Small Areas

1. The Lobular Giant Movement Detector neurone (LGMD) of Schistocerca responds with spikes when small areas of the visual field change in luminance. Previous work has shown that changes of +/− 1 log 10 unit are enough to produce maximal ON and OFF responses. 2. Using a 5 degree test area, it is shown that the number of spikes generated by such a stimulus depends on the luminance of the surrounding area. When the surround is dark, the response is maximal; when it is brightly lit, the response is minimal. Intermediate intensities produce intermediate values of response. A X 2 change in response is produced by about 3 log 10 units change in surround intensity. 3. A bright annulus, with diameters of 10-5 degrees and 25-8 degrees, inhibits both ON and OFF responses when concentric with the 5 degree test area, but not when it is 30 degrees eccentric to the test area. The inhibitory effect shows no decrease after 4 min. 4. These results are interpreted to indicate a tonic lateral inhibitory network, sited peripherally in the optic lobe prior to the divergence of the separate ON and OFF channels found in the projection from the medulla to the LGMD. It is probably identical with that described for the lamina by previous workers.

scholarly journals Stochastic re-calibration: contextual effects on perceived tilt

2006 ◽  
Vol 273 (1601) ◽  
pp. 2681-2686 ◽  
Author(s):  
Joshua A Solomon ◽  
Michael J Morgan
Keyword(s):  
Visual Field ◽  
Visual System ◽  
Lateral Inhibition ◽  
Human Visual System ◽  
Contextual Effects ◽  
Letter Recognition ◽  
Tilt Illusion ◽  
Reference Orientation ◽  
The Difference

The human visual system exaggerates the difference between the tilts of adjacent lines or grating patches. In addition to this tilt illusion, we found that oblique flanks reduced acuity for small changes of tilt in the centre of the visual field. However, no flanks—regardless of their tilts—decreased sensitivity to contrast. Thus, the foveal tilt illusion should not be attributed to orientation-selective lateral inhibition. Nor is it similar to conventional crowding, which typically does not impair letter recognition in the fovea. Our observers behaved as though the reference orientation (horizontal) had a small tilt in the direction of the flanks. We suggest that the extent of this re-calibration varies randomly over trials, and we demonstrate that this stochastic re-calibration can explain flank-induced acuity loss in the fovea.

Peripheral Movement, Induced Movement, and Aftereffects from Induced Movement

Perception ◽  
1981 ◽  
Vol 10 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Anthony H Reinhardt-Rutland
Keyword(s):  
Visual Field ◽  
Visual System ◽  
Lateral Inhibition ◽  
Static Field ◽  
Relative Movement ◽  
Partial Explanation ◽  
Peripheral Location

Substantial rotatory induced movement and aftereffects associated with induced movement were observed in a large static patterned disc bounded at its periphery by a rotating patterned annulus. The area of the annulus was less than one tenth that of the disc, so its peripheral location seemed to be important in eliciting these phenomena. This was confirmed in two experiments comparing a peripheral annulus and a relatively central annulus in their ability to elicit induced movement and aftereffects in the same large static field. Aspects of the vection (induced self-movement) phenomenon may have been involved in generation of induced movement. This suggested that the motion-inducing properties of the peripheral annulus might have derived from: (i) its eccentric location in the perceiver's visual field; or (ii) its location with regard to the display itself. Two further experiments showed that (ii) was important for the elicitation of both induced movement and the aftereffects, and (i) was important for the elicitation of induced movement. Neurons responsive to relative movement in conjunction with lateral inhibition may provide a partial explanation for these effects. However, they do not explain why the visual system can assign considerable movement to a large static field under the conditions of these experiments.

Lateral Inhibition in the Central Visual Field of an Amblyopic Subject

1973 ◽  
Vol 76 (2) ◽  
pp. 225-228 ◽  
Author(s):  
Theodore Lawwill ◽  
Guy Meur ◽  
Cleve W. Howard
Keyword(s):  
Visual Field ◽  
Lateral Inhibition ◽  
Central Visual Field

Analysis of 2D and 3D defects associated with precipitation of Cu in silicon

1991 ◽  
Vol 49 ◽  
pp. 870-871
Author(s):  
P.M. Rice ◽  
MJ. Kim ◽  
R.W. Carpenter
Keyword(s):  
Colony Growth ◽  
Dark Field ◽  
Dark Side ◽  
Silicide Phase ◽  
Strain Fields ◽  
Near Surface ◽  
Unknown Composition ◽  
Secondary Precipitates ◽  
20 Nm ◽  
2D And 3D

Extrinsic gettering of Cu on near-surface dislocations in Si has been the topic of recent investigation. It was shown that the Cu precipitated hetergeneously on dislocations as Cu silicide along with voids, and also with a secondary planar precipitate of unknown composition. Here we report the results of investigations of the sense of the strain fields about the large (~100 nm) silicide precipitates, and further analysis of the small (~10-20 nm) planar precipitates.Numerous dark field images were analyzed in accordance with Ashby and Brown's criteria for determining the sense of the strain fields about precipitates. While the situation is complicated by the presence of dislocations and secondary precipitates, micrographs like those shown in Fig. 1(a) and 1(b) tend to show anomalously wide strain fields with the dark side on the side of negative g, indicating the strain fields about the silicide precipitates are vacancy in nature. This is in conflict with information reported on the η'' phase (the Cu silicide phase presumed to precipitate within the bulk) whose interstitial strain field is considered responsible for the interstitial Si atoms which cause the bounding dislocation to expand during star colony growth.

The Dark Side of Sweet Dreams

2006 ◽  
Vol 40 (12) ◽  
pp. 30
Author(s):  
BARBARA J. HOWARD
Keyword(s):  
Dark Side
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