scholarly journals Nearby contours abolish the binocular advantage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Lev ◽  
Jian Ding ◽  
Uri Polat ◽  
Dennis M. Levi
Keyword(s):  
Detection Threshold ◽  
Gain Control ◽  
Binocular Viewing ◽  
Monocular Viewing ◽  
Low Contrast ◽  
Natural Vision ◽  
Low Luminance ◽  
Appearance Matching ◽  
Contrast Discrimination ◽  
Contrast Matching

AbstractThat binocular viewing confers an advantage over monocular viewing for detecting isolated low luminance or low contrast objects, has been known for well over a century; however, the processes involved in combining the images from the two eyes are still not fully understood. Importantly, in natural vision, objects are rarely isolated but appear in context. It is well known that nearby contours can either facilitate or suppress detection, depending on their distance from the target and the global configuration. Here we report that at close distances collinear (but not orthogonal) flanking contours suppress detection more under binocular compared to monocular viewing, thus completely abolishing the binocular advantage, both at threshold and suprathreshold levels. In contrast, more distant flankers facilitate both monocular and binocular detection, preserving a binocular advantage up to about four times the detection threshold. Our results for monocular and binocular viewing, for threshold contrast discrimination without nearby flankers, can be explained by a gain control model with uncertainty and internal multiplicative noise adding additional constraints on detection. However, in context with nearby flankers, both contrast detection threshold and suprathreshold contrast appearance matching require the addition of both target-to-target and flank-to-target interactions occurring before the site of binocular combination. To test an alternative model, in which the interactions occur after the site of binocular combination, we performed a dichoptic contrast matching experiment, with the target presented to one eye, and the flanks to the other eye. The two models make very different predictions for abutting flanks under dichoptic conditions. Interactions after the combination site predict that the perceived contrast of the flanked target will be strongly suppressed, while interactions before the site predict the perceived contrast will be more or less veridical. The data are consistent with the latter model, strongly suggesting that the interactions take place before the site of binocular combination.

Binocular and Monocular Coincidence-Anticipation Timing Responses

2018 ◽  
pp. 186-199
Keyword(s):  
Standard Deviation ◽  
Binocular Viewing ◽  
Monocular Viewing ◽  
Stimulus Velocity ◽  
Time To Collision ◽  
Dominant Eye ◽  
Response Errors ◽  
And Training

Background Coincidence-anticipation timing (CAT) responses require individuals to determine the time at which an approaching object will arrive at (time to collision) or pass by (time to passage) the observer and to then make a response coincident with this time. Previous studies suggest that under some conditions time to collision estimates are more accurate when binocular and monocular cues are combined. The purpose of this study was to compare binocular and monocular coincidence anticipation timing responses with the Bassin Anticipation Timer, a device for testing and training CAT responses. Methods: Useable data were obtained from 20 participants. Coincidence-anticipation timing responses were determined using a Bassin Anticipation Timer over a range of approaching stimulus linear velocities of 5 to 40mph. Participants stood to the left side of the Bassin Anticipation track. The track was below eye height. The participants’ task was to push a button to coincide with arrival of the approaching stimulus at a location immediately adjacent to the participant. CAT responses were made under three randomized conditions: binocular viewing, monocular dominant eye viewing, and monocular non-dominant eye viewing. Results: Signed (constant), unsigned (absolute), and variable (standard deviation) CAT response errors were determined and compared across viewing conditions at each stimulus velocity. There were no significant differences in CAT errors between the conditions at any stimulus velocity, although the differences in signed and unsigned errors approached significance at 40mph. Conclusions: The addition of binocular cues did not result in a reduction in coincidence anticipation timing response errors compared to the monocular viewing conditions. There were no differences in CAT response errors between the monocular dominant eye viewing and monocular non-dominant eye viewing conditions.

Spatial frequency analsis in early visual processing

1980 ◽  
Vol 290 (1038) ◽  
pp. 11-22 ◽  
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Spatial Information ◽  
Multiple Channels ◽  
Low Contrast ◽  
Local Sign ◽  
Early Visual Processing ◽  
Low Luminance ◽  
Lowered Sensitivity ◽  
Prior Adaptation

The existence of multiple channels, or multiple receptive field sizes, in the visual system does not commit us to any particular theory of spatial encoding in vision. However, distortions of apparent spatial frequency and width in a wide variety of conditions favour the idea that each channel carries a width- or frequency-related code or ‘label’ rather than a ‘local sign’ or positional label. When distortions of spatial frequency occur without prior adaptation (e.g. at low contrast or low luminance) they are associated with lowered sensitivity, and may be due to a mismatch between the perceptual labels and the actual tuning of the channels. A low-level representation of retinal space could be constructed from the spatial information encoded by the channels, rather than being projected intact from the retina.

Dynamic shifts of the contrast-response function

1997 ◽  
Vol 14 (3) ◽  
pp. 577-587 ◽  
Author(s):  
Jonathan D. Victor ◽  
Mary M. Conte ◽  
Keith P. Purpura
Keyword(s):  
Gain Control ◽  
Human Vision ◽  
High Contrast ◽  
Contrast Level ◽  
Low Contrast ◽  
Contrast Gain ◽  
Contrast Response Function ◽  
Stimuli Response ◽  
Response Phase ◽  
Contrast Response

AbstractWe recorded visual evoked potentials in response to square-wave contrast-reversal checkerboards undergoing a transition in the mean contrast level. Checkerboards were modulated at 4.22 Hz (8.45-Hz reversal rate). After each set of 16 cycles of reversals, stimulus contrast abruptly switched between a “high” contrast level (0.06 to 1.0) to a “low” contrast level (0.03 to 0.5). Higher contrasts attenuated responses to lower contrasts by up to a factor of 2 during the period immediately following the contrast change. Contrast-response functions derived from the initial second following a conditioning contrast shifted by a factor of 2–4 along the contrast axis. For low-contrast stimuli, response phase was an advancing function of the contrast level in the immediately preceding second. For high-contrast stimuli, response phase was independent of the prior contrast history. Steady stimulation for periods as long as 1 min produced only minor effects on response amplitude, and no detectable effects on response phase. These observations delineate the dynamics of a contrast gain control in human vision.

Gaze-Accuracy during Monocular and Binocular Viewing

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 371-371
Author(s):  
R M Steinman ◽  
T I Forofonova ◽  
J Epelboim ◽  
M R Stepanov
Keyword(s):  
Eye Movements ◽  
Affirmative Answer ◽  
Binocular Viewing ◽  
Control Limit ◽  
Monocular Viewing ◽  
Gaze Control ◽  
The Gaze

Epelboim et al (1996 Vision Research35 3401 – 3422) reported that cyclopean gaze errors were smaller than either eye's during tapping and looking-only tasks. This raised two questions: (i) does cyclopean gaze accuracy require binocular input, and (ii) when only one eye sees, is its gaze more accurate than the patched eye's? Most oculomotorists probably expect an affirmative answer to both. Neither expectation was fulfilled. The Maryland Revolving Field Monitor recorded, with exceptional accuracy, eye movements of two unrestrained subjects tapping or only looking, in a specified order, at four randomly positioned LEDs, with monocular or binocular viewing. Subjects either tapped with their finger tips naturally, or unnaturally via a rod (2 mm diameter, 1.5 cm long), glued to a sewing thimble. Instructions were to be fast, but make no order errors. With binocular viewing, cyclopean gaze accuracy was best during looking-only. During natural tapping, gaze errors increased, becoming no smaller than success required. Both tasks were learned equally fast, but as expected, the younger subject (aged 27 years) performed ∼ 40% faster than the older subject (aged 69 years). Unnatural, monocular viewing produced odd results, eg cyclopean gaze error was smallest when only one eye could see in some conditions. Only the older subject served in the unnatural tapping task because the younger's errors were too close to his gaze control limit. The older subject, who was suitable, reduced his cyclopean gaze error by 56%, from 1.4 to 0.9 deg. These results support our claim that the gaze error allowed is adjusted to the visuomotor demands of different tasks.

scholarly journals Systematic misestimation in a vernier task arising from contrast mismatch

2008 ◽  
Vol 25 (3) ◽  
pp. 365-370 ◽  
Author(s):  
HAO SUN ◽  
BARRY B. LEE ◽  
RIGMOR C. BARAAS
Keyword(s):  
Ganglion Cells ◽  
Gain Control ◽  
Phase Advance ◽  
Target Pair ◽  
Control Mechanisms ◽  
Low Contrast ◽  
Contrast Gain ◽  
Contrast Gain Control ◽  
Cell Responses ◽  
High Contrast Grating

Luminance signals mediated by the magnocellular (MC) pathway play an important role in vernier tasks. MC ganglion cells show a phase advance in their responses to sinusoidal stimuli with increasing contrast due to contrast gain control mechanisms. If the phase information in MC ganglion cell responses were utilized by central mechanisms in vernier tasks, one might expect systematic errors caused by the phase advance. This systematic error may contribute to the contrast paradox phenomenon, where vernier performance deteriorates, rather than improves, when only one of the target pair increases in contrast. Vernier psychometric functions for a pair of gratings of mismatched contrast were measured to seek such misestimation. In associated electrophysiological experiments, MC and parvocellular (PC) ganglion cells' responses to similar stimuli were measured to provide a physiological reference. The psychophysical experiments show that a high-contrast grating is perceived as phase advanced in the drift direction compared to a low-contrast grating, especially at a high drift rate (8 Hz). The size of the phase advance was comparable to that seen in MC cells under similar stimulus conditions. These results are consistent with the MC pathway supporting vernier performance with achromatic gratings. The shifts in vernier psychometric functions were negligible for pairs of chromatic gratings under the conditions tested here, consistent with the lack of phase advance both in responses of PC ganglion cells and in frequency-doubled chromatic responses of MC ganglion cells.

Assessment of Depth Perception in Cats

Perception ◽  
1979 ◽  
Vol 8 (4) ◽  
pp. 389-396 ◽  
Author(s):  
Donald E Mitchell ◽  
Martin Kaye ◽  
Brian Timney
Keyword(s):  
Depth Perception ◽  
Binocular Viewing ◽  
Monocular Viewing

A behavioural method is described for the assessment of depth perception of kittens. Measurement is made of the smallest separation in depth that can be discriminated between two adjacent stimuli under both monocular and binocular viewing conditions. Normal animals can discriminate much smaller separations in depth when using two eyes than with monocular viewing, implying the presence of a cue to depth that is uniquely available with binocular viewing. The test provides a quick and reliable way of screening animals for stereopsis.

Attentional Recruitment of Inter-Areal Recurrent Networks for Selective Gain Control

2002 ◽  
Vol 14 (7) ◽  
pp. 1669-1689 ◽  
Author(s):  
Richard H. R. Hahnloser ◽  
Rodney J. Douglas ◽  
Klaus Hepp
Keyword(s):  
Receptive Field ◽  
Network Architecture ◽  
Receptive Fields ◽  
Sensory Information ◽  
Gain Control ◽  
External Noise ◽  
Stimulus Selection ◽  
Low Contrast ◽  
Winner Take All ◽  
Higher Visual Areas

There is strong anatomical and physiological evidence that neurons with large receptive fields located in higher visual areas are recurrently connected to neurons with smaller receptive fields in lower areas. We have previously described a minimal neuronal network architecture in which top-down attentional signals to large receptive field neurons can bias and selectively read out the bottom-up sensory information to small receptive field neurons (Hahnloser, Douglas, Mahowald, & Hepp, 1999). Here we study an enhanced model, where the role of attention is to recruit specific inter-areal feedback loops (e.g., drive neurons above firing threshold). We first illustrate the operation of recruitment on a simple example of visual stimulus selection. In the subsequent analysis, we find that attentional recruitment operates by dynamical modulation of signal amplification and response multistability. In particular, we find that attentional stimulus selection necessitates increased recruitment when the stimulus to be selected is of small contrast and of small distance away from distractor stimuli. The selectability of a low-contrast stimulus is dependent on the gain of attentional effects; for example, low-contrast stimuli can be selected only when attention enhances neural responses. However, the dependence of attentional selection on stimulus-distractor distance is not contingent on whether attention enhances or suppresses responses. The computational implications of attentional recruitment are that cortical circuits can behave as winner-take-all mechanisms of variable strength and can achieve close to optimal signal discrimination in the presence of external noise.

scholarly journals Rhythmic modulation of visual contrast discrimination triggered by action

2016 ◽  
Vol 283 (1831) ◽  
pp. 20160692 ◽  
Author(s):  
Alessandro Benedetto ◽  
Donatella Spinelli ◽  
M. Concetta Morrone
Keyword(s):  
Temporal Dynamics ◽  
Luminance Contrast ◽  
Suppression Effect ◽  
Visual Contrast ◽  
Low Luminance ◽  
Brain Rhythm ◽  
Rhythmic Oscillation ◽  
Visual Motor ◽  
Contrast Discrimination ◽  
Different Levels

Recent evidence suggests that ongoing brain oscillations may be instrumental in binding and integrating multisensory signals. In this experiment, we investigated the temporal dynamics of visual–motor integration processes. We show that action modulates sensitivity to visual contrast discrimination in a rhythmic fashion at frequencies of about 5 Hz (in the theta range), for up to 1 s after execution of action. To understand the origin of the oscillations, we measured oscillations in contrast sensitivity at different levels of luminance, which is known to affect the endogenous brain rhythms, boosting the power of alpha-frequencies. We found that the frequency of oscillation in sensitivity increased at low luminance, probably reflecting the shift in mean endogenous brain rhythm towards higher frequencies. Importantly, both at high and at low luminance, contrast discrimination showed a rhythmic motor-induced suppression effect, with the suppression occurring earlier at low luminance. We suggest that oscillations play a key role in sensory–motor integration, and that the motor-induced suppression may reflect the first manifestation of a rhythmic oscillation.

Examining the effects of stimulus location and monocular-binocular viewing on the sound-induced flash illusion

2020 ◽  
Author(s):  
Jenna Cao ◽  
Nickolas F. Goenadi ◽  
Emma L. Neto ◽  
Isabel R. Shapiro
Keyword(s):  
Visual Stimulus ◽  
Representative Sample ◽  
Stimulus Location ◽  
Audiovisual Integration ◽  
Binocular Viewing ◽  
Monocular Viewing ◽  
Viewing Condition ◽  
Integration Model ◽  
Future Studies ◽  
Data Analyses

The present study aimed to determine whether stimulus location (central or peripheral) or eye viewing condition (binocular, dominant monocular, or non-dominant monocular) had a greater magnitude of effect on perception of the sound-induced flash illusion (SIFI). Both the fission illusion (when one flash paired with two beeps is perceived as two flashes) and the fusion illusion (when two flashes paired with one beep are perceived as one flash) were measured in all location and eye viewing conditions. Analyses revealed significant fission and fusion illusions in all conditions. Additionally, we found significant differences in central and peripheral criterion levels that were driven by differences between binocular and monocular viewing conditions. Data analyses demonstrated that location of the visual stimulus had a greater magnitude of effect on the illusion than eye viewing condition. Our findings add to the growing literature supporting the mechanisms underlying central-peripheral eccentricity, and contradict the optimal integration model of the SIFI. The implications of these results would help better our understanding of the SIFI and audiovisual integration. Future studies must be conducted to confirm these results in a more representative sample.

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