Higher-Order Factors Influencing the Perception of Sliding and Coherence of a Plaid

Perception ◽  
1992 ◽  
Vol 21 (5) ◽  
pp. 583-598 ◽  
Author(s):  
Frank L Kooi ◽  
Karen K De Valois ◽  
Eugene Switkes ◽  
David H Grosof
Keyword(s):  
Sine Wave ◽  
Higher Order ◽  
Viewing Time ◽  
Learning Effects ◽  
Factors Influencing ◽  
Stimulus Parameters ◽  
Sine Wave Gratings

The effect of several new stimulus parameters on the perception of a moving plaid pattern (the sum of two sine-wave gratings) were tested. It was found that: (i) the degree of perceived sliding is strongly influenced by the aperture configuration through which the plaid is viewed; (ii) the chromaticity of the sinusoidal components affects coherence in that more sliding is observed when the plaid components differ in hue, and there is less sliding when they are of the same hue; (iii) equiluminant plaids made of components equal in color almost never show any sliding; and (iv) sliding increases with viewing time. The coherence—sliding percept must therefore be influenced by color, by global interactions, and by adaptation or learning effects, thus suggesting a higher-level influence. These results are most easily modelled by separating the decision to carry out recombination from the process of recombination.

Figure and Ground in Space and Time: 1. Temporal Response Surfaces of Perceptual Organization

Perception ◽  
1989 ◽  
Vol 18 (5) ◽  
pp. 627-637 ◽  
Author(s):  
Victor Klymenko ◽  
Naomi Weisstein
Keyword(s):  
Spatial Frequency ◽  
Temporal Frequency ◽  
Sine Wave ◽  
Response Surfaces ◽  
Viewing Time ◽  
Temporal Response ◽  
Frequency Condition ◽  
Spatial Frequencies ◽  
Sine Wave Gratings ◽  
Ground Organization

The figure – ground organization of an ambiguous bipartite pattern can be manipulated by altering the temporal-frequency content of the two regions of the pattern. Ambiguous patterns in which the two regions of each pattern contained sine-wave gratings of either 8, 4, 1, or 0.5 cycles deg−1 undergoing contrast reversal at rates of 0, 3.75, 7.5, or 15 Hz were tested for figure–ground organization under conditions of equated space-averaged and time-averaged luminance and perceived contrast. All combinations of temporal-frequency differences between the two regions were tested at each spatial frequency. The data are reported for two levels of temporal resolution (15 and 30 s). The pattern region with the relatively higher temporal frequency tended to be seen as the background a higher percentage of the viewing time. There were significant linear trends for the appearance as background of the region of higher temporal frequency with respect to the magnitude of the temporal-frequency difference between the two regions of each pattern for all spatial frequencies and data intervals except the final 15 s interval of the lowest (0.5 cycle deg−1) spatial-frequency condition.

Analysis Of Factors Influencing Acupuncture Clinical Effects: A Systematic Review

2021 ◽  
Author(s):  
Yali Liu ◽  
Honglin Jiang ◽  
Xiaotong Li ◽  
Xingyue Yang
Keyword(s):  
Systematic Review ◽  
Individual Difference ◽  
Current Status ◽  
Clinical Effects ◽  
High Quality ◽  
Psychological States ◽  
Factors Influencing ◽  
High Quality Evidence ◽  
Stimulus Parameters ◽  
Quality Evidence

Background: Acupuncture therapy has been widely applied all around the world. But there still lacks high-quality evidence to evaluate its clinical effects, safety and cost-effectiveness, which seriously restricts its further promotion and development. Acupuncture, as an operational intervention, is more complex than drug therapy. Factors involved in the acupuncture operation process, such as individual and interventional factors, may affect clinical effects. Purpose:s Through this systematic review, we attempt to analyze the current status of studies about the key factors influencing clinical effects, so as to provide evidence for the design of acupuncture studies. Methods: A literature research was conducted in six databases until May, 2020. Studies were screened and assessed by two authors independently. Data extraction was made after screening. We extracted the basic information of these studies, including publishing years and countries, population and factors influencing clinical effects.Results: Through the initial search in these six database, 6404 records were retrieved. After duplication and screening, a total of 355 studies were finally included in the qualitative analysis. About 88.5% of these studies were conducted in China with increasing number in the past decades, covering neurological disorders, orthopedic disorders, obstetrical and gynecological diseases, digestive diseases and so on; 239 studies focused on stimulus parameters which may influence effects, accounting for 67.3%, and 128, 44, 39, 32, 15, 11 studies discussed acupoints, patients’ pathological states, individual difference, psychological states, deqi, and other factors separately. Conclusion: There are more and more studies focusing on factors influencing acupuncture clinical effects, including stimulus parameters, acupoints, individual difference, patient pathological and psychological states. Based on this systematic review, several ignored factors should be considered for future researches, and more scientifically and objectively high quality evidence should also be proved.

The Dependence of Monocular Rivalry on Spatial Frequency

Perception ◽  
1973 ◽  
Vol 2 (2) ◽  
pp. 127-133 ◽  
Author(s):  
J Atkinson ◽  
F W Campbell ◽  
A Fiorentini ◽  
L Maffei
Keyword(s):  
Spatial Frequency ◽  
Sine Wave ◽  
Ambiguous Figures ◽  
Alternation Rate ◽  
Higher Harmonics ◽  
Square Wave ◽  
Sharp Edges ◽  
Harmonic Components ◽  
Sine Wave Gratings

The effect of change in spatial frequency on the alternation rate of two crossed gratings was measured. The rate was found to decrease with increase in spatial frequency, but to change only little with contrast. Low alternation rate was observed for crossed square-wave gratings compared to crossed sine-wave gratings; here the rate of rivalry is largely dependent upon the presence or absence of the first three harmonic components rather than the higher harmonics which contribute to the sharp edges of the square wave. The results are compared with those for some ambiguous figures.

Visual Persistence as a Function of Spatial Frequency and Age

Perception ◽  
1980 ◽  
Vol 9 (5) ◽  
pp. 529-532 ◽  
Author(s):  
William Lovegrove ◽  
Margaret Heddle
Keyword(s):  
Spatial Frequency ◽  
Age Groups ◽  
Sine Wave ◽  
Visual Persistence ◽  
Sine Wave Gratings

Duration of visual persistence for sine-wave gratings of 1, 2, 4, 8, 12, and 16 cycles deg−1 was determined for seven-year-old, ten-year-old, and thirteen-year-old children. It was found that there was a decrease in persistence duration with age but the slope of this function for the different age groups did not change.

Contrast sensitivity for oscillating sine wave gratings during ocular fixation and pursuit

1988 ◽  
Vol 28 (7) ◽  
pp. 819-826 ◽  
Author(s):  
J.P. Flipse ◽  
G.J.v.d. Wildt ◽  
M. Rodenburg ◽  
C.J. Keemink ◽  
P.G.M. Knol
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave ◽  
Ocular Fixation ◽  
Sine Wave Gratings

Short-Term Memory for Speed

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 156-156
Author(s):  
P Thompson ◽  
R Stone ◽  
E Walton
Keyword(s):  
Spatial Frequency ◽  
Short Term Memory ◽  
Temporal Frequency ◽  
Frequency Discrimination ◽  
Sine Wave ◽  
Short Term ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Speed Discrimination ◽  
Sine Wave Gratings

We have measured the retention of information about stimulus speed in visual short-term memory by measuring speed discrimination in a two-interval forced-choice task. We have also measured such discrimination in conditions where a ‘memory masker’ is presented during the interstimulus interval (ISI) in a fashion analogous to the experiment of Magnussen et al (1991 Vision Research31 1213 – 1219). Magnussen et al found that spatial frequency discrimination was disrupted when the mask had a spatial frequency that differed from the test spatial frequency by an octave or more. We have investigated the speed discrimination of 8 Hz, 1 cycle deg−1 drifting sine-wave gratings with the following drifting masks presented in the ISI: (i) 8 Hz 1 cycle deg−1, same direction as the test; (ii) 8 Hz, 8 cycles deg−1, opposite direction to the test; (iii) 8 Hz, 8 cycles deg−1, same direction as the test; (iv) 24 Hz, 3 cycles deg−1, same direction as the test. These masks were chosen to investigate whether the temporal frequency, the spatial frequency, the speed, or the direction of motion of the mask affected retention. We found that in none of these conditions was the discrimination of the test gratings impaired significantly. This pattern of results is therefore different from that found with spatial frequency discrimination and suggests that, whatever mechanism is responsible for the retention of information about speed, it is different from that responsible for the retention of information about spatial frequency.

Temporal and Spatial Frequency Tuning of the Flicker Motion Aftereffect

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 12-12
Author(s):  
P J Bex ◽  
F A J Verstraten ◽  
I Mareschal
Keyword(s):  
Spatial Frequency ◽  
Frequency Tuning ◽  
Temporal Frequency ◽  
Motion Aftereffect ◽  
Sine Wave ◽  
Test Grating ◽  
Spatial Frequency Tuning ◽  
Spatial Frequencies ◽  
Low Pass ◽  
Sine Wave Gratings

The motion aftereffect (MAE) was used to study the temporal-frequency and spatial-frequency selectivity of the visual system at suprathreshold contrasts. Observers adapted to drifting sine-wave gratings of a range of spatial and temporal frequencies. The magnitude of the MAE induced by the adaptation was measured with counterphasing test gratings of a variety of spatial and temporal frequencies. Independently of the spatial or temporal frequency of the adapting grating, the largest MAE was found with slowly counterphasing test gratings (∼0.125 – 0.25 Hz). For slowly counterphasing test gratings (<∼2 Hz), the largest MAEs were found when the test grating was of similar spatial frequency to that of the adapting grating, even at very low spatial frequencies (0.125 cycle deg−1). However, such narrow spatial frequency tuning was lost when the temporal frequency of the test grating was increased. The data suggest that MAEs are dominated by a single, low-pass temporal-frequency mechanism and by a series of band-pass spatial-frequency mechanisms at low temporal frequencies. At higher test temporal frequencies, the loss of spatial-frequency tuning implicates separate mechanisms with broader spatial frequency tuning.

scholarly journals Spatiotemporal Properties of Fast and Slow Neurons in the Pretectal Nucleus Lentiformis Mesencephali in Pigeons

2000 ◽  
Vol 84 (5) ◽  
pp. 2529-2540 ◽  
Author(s):  
Douglas R. W. Wylie ◽  
Nathan A. Crowder
Keyword(s):  
Temporal Frequency ◽  
Receptive Fields ◽  
Sine Wave ◽  
Accessory Optic System ◽  
Stimulus Velocity ◽  
Preferred Direction ◽  
Pretectal Nucleus ◽  
Contralateral Eye ◽  
Sine Wave Gratings ◽  
Self Motion

Neurons in the pretectal nucleus lentiformis mesencephali (LM) are involved in the analysis of optic flow that results from self-motion. Previous studies have shown that LM neurons have large receptive fields in the contralateral eye, are excited in response to largefield stimuli moving in a particular (preferred) direction, and are inhibited in response to motion in the opposite (anti-preferred) direction. We investigated the responses of LM neurons to sine wave gratings of varying spatial and temporal frequency drifting in the preferred and anti-preferred directions. The LM neurons fell into two categories. “Fast” neurons were maximally excited by gratings of low spatial [0.03–0.25 cycles/° (cpd)] and mid-high temporal frequencies (0.5–16 Hz). “Slow” neurons were maximally excited by gratings of high spatial (0.35–2 cpd) and low-mid temporal frequencies (0.125–2 Hz). Of the slow neurons, all but one preferred forward (temporal to nasal) motion. The fast group included neurons that preferred forward, backward, upward, and downward motion. For most cells (81%), the spatial and temporal frequency that elicited maximal excitation to motion in the preferred direction did not coincide with the spatial and temporal frequency that elicited maximal inhibition to gratings moving in the anti-preferred direction. With respect to motion in the anti-preferred direction, a substantial proportion of the LM neurons (32%) showed bi-directional responses. That is, the spatiotemporal plots contained domains of excitation in addition to the region of inhibition. Neurons tuned to stimulus velocity across different spatial frequency were rare (5%), but some neurons (39%) were tuned to temporal frequency. These results are discussed in relation to previous studies of the responses of neurons in the accessory optic system and pretectum to drifting gratings and other largefield stimuli.

Spatial frequency tuning in the visual evoked potential elicited by sine-wave gratings

1984 ◽  
Vol 24 (9) ◽  
pp. 1057-1062 ◽  
Author(s):  
J.L. Reed ◽  
M.S. Marx ◽  
J.G. May
Keyword(s):  
Spatial Frequency ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Frequency Tuning ◽  
Sine Wave ◽  
Spatial Frequency Tuning ◽  
Sine Wave Gratings ◽  
Visual Evoked
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