Dynamics of absolute and relative disparity processing in human visual cortex

Kaestner, Milena; Evans, Marissa L; Chen, Yulan D.; Norcia, Anthony M.

doi:10.1016/j.neuroimage.2022.119186

Cited by 8 publications

(47 citation statements)

References 85 publications

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“…Odd-harmonic responses are strongly dependent on the availability of multiple disparities in the visual field 44 – 46 consistent with the differences we see between plane and grating responses. Odd harmonic responses are tuned for cyclopean spatial frequency while even harmonics are not 35 , consistent with the even harmonics arising from mechanisms sensitive to absolute disparity. Here we add to these results by demonstrating that relative disparity is extracted after an initial transient response to absolute disparity that can be linked to even harmonic response components.…”

Section: Discussionsupporting

confidence: 57%

“…‘ Odd’ and ‘even’ filters in the Fourier domain can be used to reveal transient and sustained response components that have been associated with the extraction of plane and grating disparity signals respectively 35 . The logic of the filtering is based on prior work with contrast responses 36 .…”

Section: Resultsmentioning

confidence: 99%

“…DRDS stimuli were like those described in detail elsewhere 35 . An example of side-by-side binocular half-images is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…and even (2F1, 4F1, 6F1, etc.) harmonic components as these have been found to have different functional properties 35 .

Figure 7 Two key stages in the data processing pipeline.…”

Section: Methodsmentioning

confidence: 99%

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Cognitive penetrability of scene representations based on horizontal image disparities

Chen

Kaestner

Norcia

2022

Sci Rep

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The structure of natural scenes is signaled by many visual cues. Principal amongst them are the binocular disparities created by the laterally separated viewpoints of the two eyes. Disparity cues are believed to be processed hierarchically, first in terms of local measurements of absolute disparity and second in terms of more global measurements of relative disparity that allow extraction of the depth structure of a scene. Psychophysical and oculomotor studies have suggested that relative disparities are particularly relevant to perception, whilst absolute disparities are not. Here, we compare neural responses to stimuli that isolate the absolute disparity cue with stimuli that contain additional relative disparity cues, using the high temporal resolution of EEG to determine the temporal order of absolute and relative disparity processing. By varying the observers’ task, we assess the extent to which each cue is cognitively penetrable. We find that absolute disparity is extracted before relative disparity, and that task effects arise only at or after the extraction of relative disparity. Our results indicate a hierarchy of disparity processing stages leading to the formation of a proto-object representation upon which higher cognitive processes can act.

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Section: Discussionsupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

“…DRDS stimuli were like those described in detail elsewhere 35 . An example of side-by-side binocular half-images is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…and even (2F1, 4F1, 6F1, etc.) harmonic components as these have been found to have different functional properties 35 .

Figure 7 Two key stages in the data processing pipeline.…”

Section: Methodsmentioning

confidence: 99%

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Cognitive penetrability of scene representations based on horizontal image disparities

Chen

Kaestner

Norcia

2022

Sci Rep

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“…Preprocessing was performed as in previous studies from the lab (Kaestner et al, 2022). Briefly, raw EEG data sets were preprocessed with a 0.3-50 Hz bandpass filter using EGI software.…”

Section: Methodsmentioning

confidence: 99%

Stability of steady-state visual evoked potential contrast response functions

Ash

Nix

Norcia

2022

Preprint

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A repeated measure of neural activity that is stable over time when unperturbed is needed to be able to meaningfully measure neuroplastic changes in the brain. With sensory-evoked potentials in particular, repeated presentation of stimuli can generate neuroplasticity by itself under certain conditions. We assessed the repeated-measure within-day and across-day stability of the steady-state visual-evoked potential (ssVEP), a high signal-to-noise electrophysiological readout of neural activity in human visual cortex, in preparation for studies of visual cortical neuroplasticity. Steady-state VEP contrast-sweep responses were measured daily for 4 days (four 20-trial blocks per day, 22 participants). Response amplitudes were stable in individual participants, with measured across-block and across-day coefficients of variation (CV= SD / Mean) of 12±1% and 19±2%, respectively. No consistent changes in response amplitude were observed either across blocks or across days. We conclude that contrast-sweep steady-state VEPs provide a stable human neurophysiological measure well-suited for repeated-measures studies.

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Absolute and relative disparity mechanisms revealed by an equivalent noise analysis

Ding,

Lu,

Levi

2024

Sci Rep

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The precision of stereopsis and vergence are ultimately limited by internal binocular disparity noise. Here we propose an equivalent noise model with both global and local internal disparity noises to provide a unified explanation of both absolute and relative disparity thresholds. To test this model, we developed a psychophysical procedure to measure the equivalent internal disparity noise by adding external disparity noise to random-Gabor-patch stereograms. We used the method of constant stimuli to measure the minimum and maximum disparity thresholds (Dmin and Dmax) for both absolute and relative disparity. Consistent with previous studies, we found that Dmin thresholds are substantially worse for absolute disparity than for relative disparity. We tested three relative disparity mechanisms: (1) the difference between the monocular separations of targets projecting to the two eyes; (2) the direct measurement of relative disparity; and (3) the difference of absolute disparities of targets. Computing the difference of absolute disparities when detecting relative disparity, Mechanism 3 cancels global noise, resulting in a much lower relative Dmin threshold, and provides a reasonable fit to the experimental data. We also found that the presence of as much as 2400 arcsec of external disparity noise does not appear to affect the Dmax threshold. This observation suggests that Dmax is implicated in a mechanism that disregards the disparity variance of individual items, relying instead on the average disparity across all items, supporting the depth model proposed in our previous study (Ding & Levi, 2021), which posits distinct mechanisms governing Dmin and Dmax thresholds.

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Dynamics of absolute and relative disparity processing in human visual cortex

Cited by 8 publications

References 85 publications

Cognitive penetrability of scene representations based on horizontal image disparities

Cognitive penetrability of scene representations based on horizontal image disparities

Stability of steady-state visual evoked potential contrast response functions

Absolute and relative disparity mechanisms revealed by an equivalent noise analysis

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