Effect of repetitive visual stimuli on behaviour and plasma corticosterone of European starlings

2005 ◽  
Vol 55 (3) ◽  
pp. 245-258 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Temporal Frequency ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Plasma Corticosterone ◽  
European Starlings ◽  
Fluorescent Lamps ◽  
Spatial Frequencies ◽  
Temporal And Spatial

AbstractFlickering light can cause adverse effects in some humans, as can rhythmic spatial patterns of particular frequencies. We investigated whether birds react to the temporal frequency of standard 100 Hz fluorescent lamps and the spatial frequency of the visual surround in the manner predicted by the human literature, by examining their effects on the preferences, behaviour and plasma corticosterone of European starlings (Sturnus vulgaris). We predicted that high frequency lighting (> 30 kHz) and a relatively low spatial frequency on the walls of their cages (0.1 cycle cm−1) would be less aversive than low frequency lighting (100 Hz) and a relatively high spatial frequency (2.5 cycle cm−1). Birds had strong preferences for both temporal and spatial frequencies. These preferences did not always fit with predictions, although there was evidence that 100 Hz was more stressful than 30 kHz lighting, as birds were less active and basal corticosterone levels were higher under 100 Hz lighting. Our chosen spatial frequencies had no overall significant effect on corticosterone levels. Although there are clearly effects of, and interactions between, the frequency of the light and the visual surround on the behaviour and physiology of birds, the pattern of results is not straightforward.

Spatial Scale Interactions and Visual-Tracking Performance

Perception ◽  
1997 ◽  
Vol 26 (8) ◽  
pp. 1047-1058 ◽  
Author(s):  
Howard C Hughes ◽  
David M Aronchick ◽  
Michael D Nelson
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Visual Information ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Performance Measure ◽  
High Frequency Component ◽  
Stimulus Velocity ◽  
Spatial Frequencies ◽  
Wide Range

It has previously been observed that low spatial frequencies (≤ 1.0 cycles deg−1) tend to dominate high spatial frequencies (≥ 5.0 cycles deg−1) in several types of visual-information-processing tasks. This earlier work employed reaction times as the primary performance measure and the present experiments address the possibility of low-frequency dominance by evaluating visually guided performance of a completely different response system: the control of slow-pursuit eye movements. Slow-pursuit gains (eye velocity/stimulus velocity) were obtained while observers attempted to track the motion of a sine-wave grating. The drifting gratings were presented on three types of background: a uniform background, a background consisting of a stationary grating, or a flickering background. Low-frequency dominance was evident over a wide range of velocities, in that a stationary high-frequency component produced little disruption in the pursuit of a drifting low spatial frequency, but a stationary low frequency interfered substantially with the tracking of a moving high spatial frequency. Pursuit was unaffected by temporal modulation of the background, suggesting that these effects are due to the spatial characteristics of the stationary grating. Similar asymmetries were observed with respect to the stability of fixation: active fixation was less stable in the presence of a drifting low frequency than in the presence of a drifting high frequency.

Disparity Modulation Sensitivity for Narrow-Band-Filtered Stereograms Viewed out of the Plane of Fixation

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 94-94
Author(s):  
B Lee ◽  
B J Rogers
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Significant Interaction ◽  
Narrow Band ◽  
Low Frequency ◽  
Frequency Pattern ◽  
Spatial Frequencies ◽  
Size Disparity ◽  
Random Dot Stereograms

Narrow-band-filtered random-dot stereograms were used to determine stereo thresholds for detecting sinusoidal disparity modulations. These stereograms were designed to stimulate selectively channels tuned to luminance and corrugation spatial frequencies (Schumer and Ganz, 1979 Vision Research19 1303 – 1314). Thresholds were determined for corrugation frequencies ranging from 0.125 to 1 cycle deg−1, luminance centre spatial frequencies ranging from 1 to 8 cycles deg−1 and disparity pedestal sizes ranging from −32 to +32 min arc. For small disparity pedestals, lowest modulation thresholds were found around 0.5 cycle deg−1 corrugation frequency and 4 cycles deg−1 luminance centre spatial frequency. For large disparity pedestals (±32 arc min), lowest thresholds were shifted towards the lower corrugation frequencies (0.125 cycle deg−1) and lower luminance frequencies (2 cycles deg−1). There was a significant interaction between luminance spatial frequency and disparity pedestal size. For small pedestals, lowest thresholds were found with the highest luminance frequency pattern (4 cycles deg−1). For large pedestals, best performance shifted towards the low-frequency patterns (1 cycle deg−1). This effect demonstrates a massive reduction in stereo-efficiency for high-frequency patterns in the luminance domain at large disparity pedestals which is consistent with the ‘size-disparity relation’ proposed by previous researchers.

Inhibition and Excitation in the Locust DCMD Receptive Field: Spatial Frequency, Temporal and Spatial Characteristics

1979 ◽  
Vol 80 (1) ◽  
pp. 191-216
Author(s):  
ROBERT B. PINTER
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Visual Angle ◽  
Temporal Frequency ◽  
Low Frequency ◽  
Movement Detector ◽  
Small Target ◽  
Grating Pattern ◽  
Spatial Frequencies ◽  
Pattern Size

1. The descending contralateral movement detector (DCMD) of the locust responds vigorously to small target (ca. 5°) stimuli; this response is inhibited by simultaneous or subsequent rotation of a radial grating (windmill) pattern (subtending 19-90° of visual angle) and suppressed by earlier rotation. 2. The excitation produced in the DCMD by rotation of a radial grating pattern depends only on the spatial frequency of the stripes of the pattern, and is independent of pattern size, and of temporal frequency over the range of low values used. 3. The inhibition produced by this same stimulus similarly depends only on the spatial frequency of the stripes of the pattern, independent of pattern size, and of temporal frequency over the range of low values used. 4. As the radial grating excitation decreases with increasing spatial frequency, the inhibition increases until limited by optical and neural resolution. 5. For spatial frequencies of the radial grating pattern below 0.05 cyc/deg the radial grating patterns become excitatory. Above 0.05 cyc/deg they are inhibitory. This is the point in spatial frequency below which inhibitory grating ‘backgrounds’ become excitatory targets. 6. Inhibition decreases as the size of the radial grating pattern is decreased below 190 visual angle; at 8° or less no inhibition can be found at any spatial frequency. 7. Inhibition is greater in the posterior than anterior regions of the receptive field, and greater in the ventral than the dorsal regions. 8. Inhibition decreases as the distance between small target and the radial grating is increased, but this is influenced by the local variations of excitation and inhibition. 9. Habituation is often greater for small target and low-frequency radial grating response than for inhibited small target and high frequency grating response. 10. These results substantiate previously proposed lateral inhibition models of the acridid movement detector system.

Global Precedence, Spatial Frequency Channels, and the Statistics of Natural Images

1996 ◽  
Vol 8 (3) ◽  
pp. 197-230 ◽  
Author(s):  
Howard C. Hughes ◽  
George Nozawa ◽  
Frederick Kitterle
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Reaction Times ◽  
Low Frequency ◽  
Natural Images ◽  
Visual Pattern ◽  
Pattern Perception ◽  
Global Precedence ◽  
Processing Times ◽  
Spatial Frequencies

A great deal of evidence suggests that early in processing, retinal images are filtered by parallel, spatial frequency selective channels. We attempt to incorporate this view of early vision with the principle of global precedence, which holds that Gestalt-like processes sensitive to global image configurations tend to dominate local feature processing in human pattern perception. Global precedence is inferred from the pattern of reaction times observed when visual patterns contain multiple cues at different levels of spatial scale. Specifically, it is frequently observed that global processing times are largely unaffected by conflicting local cues, but local processing times are substantially lengthened by conflicting global cues. The asymmetry of these effects suggests the dominant role of global configurations. Since global spatial information is effectively represented by low spatial frequencies, global precedence potentially implies a low frequency dominance. The thesis is that low spatial frequencies tend to be available before information carried by higher frequency bands, producing a coarse-to-fine temporal order in visual spatial perception. It is suggested that a variety of factors contribute to the “prior entry” of low frequency information, including the high contrast gain of the magnocellular pathway, the amplitude spectra typical of natural images, and inhibitory interactions between the parallel frequency-tuned channels. Evidence suggesting a close relationship between global precedence and spatial frequency channels is provided by observations that the essential features of the global precedence effect are obtained using patterns consisting of low and high frequency sinusoids. The hypothesis that these asymmetric interference effects are due to interactions between parallel spatial channels is supported by an analysis of reaction times (RTs), which shows that RTs to redundant low and high frequency cues produce less facilitation than predictions that assume the channels are independent. In view of previous work showing that global precedence depends upon the low frequency content of the stimuli, we suggest that low spatial frequencies represent the sine qua non for the dominance of configurational cues in human pattern perception, and that this configurational dominance reflects the microgenesis of visual pattern perception. This general view of the temporal dynamics of visual pattern recognition is discussed, is considered from an evolutionary perspective, and is related to certain statistical regularities in natural scenes. Potential adaptive advantages of an interactive parallel architecture that confers an initial processing advantage to low resolution information are explored.

Organisation and Interrelationships of Functional Maps in Cat and Monkey Striate Cortex

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 356-356
Author(s):  
D Shoham ◽  
M Hübener ◽  
T Bonhoeffer ◽  
A Grinvald
Keyword(s):  
Spatial Frequency ◽  
Cytochrome Oxidase ◽  
Striate Cortex ◽  
Temporal Frequency ◽  
Activity Patterns ◽  
Ocular Dominance ◽  
High Spatial Frequency ◽  
Spatial Frequencies ◽  
Frequency Domains

Optical imaging of intrinsic signals allows mapping of the cortical functional architecture in vivo at high spatial resolution. The ability to image activity patterns evoked by many different stimuli in the same piece of cortex can provide information on the spatial relationships between different functional maps. Our findings on the organisation of multiple functional maps in cat and monkey striate cortex are reviewed. The main focus is on the recent finding in cat of two subsystems differing in their response to spatiotemporal aspects of the stimulus. We used grating stimuli of different spatial frequencies in an attempt to verify the existence of spatial frequency columns in cat area 17. Rather than observing a map of continuously changing spatial frequency across the cortical surface we found two distinct sets of domains, one preferring low and one preferring high spatial frequencies. By using different drift velocities we also found that the low-spatial-frequency domains preferred higher speeds than the high-spatial-frequency domains. Comparison of these spatiotemporal frequency domains with the cytochrome oxidase staining pattern revealed that the cytochrome oxidase blobs in cat striate cortex coincide with domains devoted to the processing of the low-spatial-frequency and high-temporal-frequency contents of the visual scene. Together with recent anatomical results these data suggest that spatiotemporal frequency domains are the manifestation of parallel streams in cat visual cortex with distinct patterns of thalamic inputs and extrastriate projections. In the same experiments we also imaged the orientation preference and ocular dominance maps. We investigated the relationships between these three columnar systems, and compared them to an earlier study of orientation, ocular dominance, and blobs in macaque striate cortex. We found systematic relationships between the three systems. While some of these relationships were much weaker than those found in monkey, the organisational principles are similar.

scholarly journals Monocular blur alters the tuning characteristics of stereopsis for spatial frequency and size

2016 ◽  
Vol 3 (9) ◽  
pp. 160273 ◽  
Author(s):  
Roger W. Li ◽  
Kayee So ◽  
Thomas H. Wu ◽  
Ashley P. Craven ◽  
Truyet T. Tran ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Narrow Band ◽  
Frequency Tuning ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Spatial Filters ◽  
Optimum Frequency ◽  
Spatial Frequencies ◽  
Coarse To Fine ◽  
Tuning Function

Our sense of depth perception is mediated by spatial filters at different scales in the visual brain; low spatial frequency channels provide the basis for coarse stereopsis, whereas high spatial frequency channels provide for fine stereopsis. It is well established that monocular blurring of vision results in decreased stereoacuity. However, previous studies have used tests that are broadband in their spatial frequency content. It is not yet entirely clear how the processing of stereopsis in different spatial frequency channels is altered in response to binocular input imbalance. Here, we applied a new stereoacuity test based on narrow-band Gabor stimuli. By manipulating the carrier spatial frequency, we were able to reveal the spatial frequency tuning of stereopsis, spanning from coarse to fine, under blurred conditions. Our findings show that increasing monocular blur elevates stereoacuity thresholds ‘selectively’ at high spatial frequencies, gradually shifting the optimum frequency to lower spatial frequencies. Surprisingly, stereopsis for low frequency targets was only mildly affected even with an acuity difference of eight lines on a standard letter chart. Furthermore, we examined the effect of monocular blur on the size tuning function of stereopsis. The clinical implications of these findings are discussed.

Recognition of Positive and Negative Bandpass-Filtered Images

Perception ◽  
1986 ◽  
Vol 15 (5) ◽  
pp. 595-602 ◽  
Author(s):  
Tony Hayes ◽  
M Concetta Morrone ◽  
David C Burr
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Visual Information ◽  
Recognition Performance ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Spatial Frequencies ◽  
Negative Images ◽  
Frequency Components

A study is reported in which the significance for vision of low- and high-spatial-frequency components of photographic positive and negative images was investigated by measuring recognition of bandpass-filtered photographs of faces. The results show that a 1.5 octave bandpass-filtered image contains sufficient visual information for good recognition performance, provided the filter is centred close to 20 cycles facewidth−1. At low spatial frequencies negatives are more difficult to recognize than positives, but at high spatial frequencies there is no difference in recognition, implying that it is the low-frequency components of negatives which present difficulties for the visual system.

Contrast sensitivity in dyslexia

1995 ◽  
Vol 12 (1) ◽  
pp. 153-163 ◽  
Author(s):  
Karen Gross-Glenn ◽  
Bernt C. Skottun ◽  
William Glenn ◽  
Alex Kushch ◽  
Robert Lingua ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
High Frequency ◽  
Temporal Summation ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Forward Masking ◽  
Baseline Condition ◽  
Transient System ◽  
Deficit Theory

AbstractContrast sensitivity was determined for dyslexic and normal readers. When testing with temporally ramped (i.e. stimuli with gradual temporal onsets and offsets) gratings of 0.6, 4.0, and 12.0 cycles/deg, we found no difference in contrast sensitivity between dyslexic readers and controls. Using 12.0 cycles/deg gratings with transient (i.e. abrupt) onsets and offsets, we found that dyslexic individuals had, compared to controls, markedly inferior contrast sensitivity at the shortest stimulus durations (i.e. 17, 34, and 102 ms). This deficit may reflect more sluggish temporal summation. There was no difference in sensitivity to 0.6 cycles/deg gratings with transient onsets and offsets. Under these conditions, the two groups showed a consistent and equal increase in sensitivity relative to the ramped baseline condition at 0.6 cycles/deg at the longer stimulus durations. This demonstrates that dyslexic readers have no deficit in their ability to detect stimulus transients, a finding which appears to be inconsistent with a transient system deficit. That detection of the low-frequency stimuli was mediated by the transient system is further indicated by the fact that these stimuli were more susceptible to forward masking than were the high-frequency stimuli. The effects of masking of both high and low spatial-frequency stimuli were about equal for dyslexic readers and controls. This is not in agreement with the transient system deficit theory, according to which one would expect there to be less masking of high spatial-frequency stimuli in the case of dyslexic readers.

Modelling of Polishing Tools for High Spatial Frequency Defect Correction on Aspherical Surfaces

2013 ◽  
Vol 554-557 ◽  
pp. 1232-1241 ◽  
Author(s):  
Antoine Goupil ◽  
Ivan Iordanoff ◽  
Jean Luc Charles ◽  
André Rinchet
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Ion Beam ◽  
Excitation Frequency ◽  
Low Frequency ◽  
High Spatial Frequency ◽  
Initial Pressure ◽  
Fused Silica ◽  
Pressure Differential ◽  
Machining Parameters

Nowadays, precision Computer Controlled Optical Surfacing (CCOS) and processes like Ion Beam Finishing (IBF) or Magneto-Rheological Finishing (MRF) allow manufacturing of fused silica optics with nanometer precision. However, High spatial frequency defects remain on the optics and need to be previously smoothed. Full aperture semi-flexible polishing tools can be used, as they can guarantee uniform pressure on low frequency patterns to preserve the pre-formed aspherical shape while maintaining a high pressure differential on high frequency defects, thus smoothing them. That behavior can be obtained with tools that combine a continuous flexible layer for low frequency compliance and a fractionate viscoelastic polishing layer for high frequency defect polishing. The main goals of this study are predicting smoothing efficiency and form control of different tools, and then determining the best tool to achieve a good balance between them. To do this, a multiscale model is developed. First, at the whole tool scale, for a given aspherical shape, the largest misfit between tools and surfaces is mathematically determined, depending on machining parameters. Then a finite-element parametric study is performed and yields for the flexible layer the best mechanical properties and thickness as well as the optimal applied force to achieve pressure homogeneity at the global aspherical shape level. Second, at the viscoelastic polishing layer level, the Discrete Element Method (DEM) is used to investigate the tool – workpiece interface. A model based on the viscoelastic cohesive beam method is developed, thus allowing taking into account the polishing layer’s dynamic response depending on the excitation frequency. The optical surface is also modeled by interpenetrated discrete elements, paving the way for a full-DEM model of the polishing layer – workpiece interface. Smoothing simulations are separated in two steps : the first one is the initial pressure application, leading to an initial state of full tool – surface contact with an homogeneous pressure. Then the tool is moved over the surface and the dynamic pressure is calculated depending on defect and polishing layer properties as well as tool kinematics. By analyzing the pressure differential on defects it becomes possible to calculate the smoothing efficiency of a given polishing layer and therefore optimize its properties depending on the defects that need to be smoothed.

scholarly journals Contrast thresholds reveal different visual masking functions in humans and praying mantises

2017 ◽  
Author(s):  
Ghaith Tarawneh ◽  
Vivek Nityananda ◽  
Ronny Rosner ◽  
Steven Errington ◽  
William Herbert ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Motion Detection ◽  
Visual Masking ◽  
High Spatial Frequency ◽  
Visual Noise ◽  
Frequency Noise ◽  
Detection Systems ◽  
Spatial Frequencies ◽  
Summary Statement ◽  
Contrast Thresholds

AbstractRecently, we showed a novel property of the Hassenstein-Reichardt detector: namely, that insect motion detection can be masked by “invisible” noise, i.e. visual noise presented at spatial frequencies to which the animals do not respond when presented as a signal. While this study compared the effect of noise on human and insect motion perception, it used different ways of quantifying masking in two species. This was because the human studies measured contrast thresholds, which were too time-consuming to acquire in the insect given the large number of stimulus parameters examined. Here, we run longer experiments in which we obtained contrast thresholds at just two signal and two noise frequencies. We examine the increase in threshold produced by noise at either the same frequency as the signal, or a different frequency. We do this in both humans and praying mantises (Sphodromantis lineola), enabling us to compare these species directly in the same paradigm. Our results confirm our earlier finding: whereas in humans, visual noise masks much more effectively when presented at the signal spatial frequency, in insects, noise is roughly equivalently effective whether presented at the same frequency or a lower frequency. In both species, visual noise presented at a higher spatial frequency is a less effective mask.Summary StatementWe here show that despite having similar motion detection systems, insects and humans differ in the effect of low and high spatial frequency noise on their contrast thresholds.

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