Random-dot Stereograms Research Articles

Uncovering the Locus of Object-Context-Based Modulations in Depth Processing Using Repetitive Transcranial Magnetic Stimulation.

Neural responses of dorsal visual area V7 and lateral occipital complex (LOC) have been shown to correlate with changes in behavioral metrics of depth sensitivity observed as a function of object context, although it is unclear as to whether the behavioral manifestation results from an alteration of early depth-specific responses in V7 or arises as a result of alterations of object-level representations at LOC that subsequently feed back to affect disparity readouts in dorsal cortex. Here, we used online transcranial magnetic stimulation (TMS) to examine the roles of these two areas in giving rise to context–disparity interactions. Stimuli were disparity-defined geometric objects rendered as random-dot stereograms, presented in geometrically plausible and implausible variations. Observers’ sensitivity to depth (depth discrimination) or object identity (plausibility discrimination) was indexed while receiving repetitive TMS at one of the two sites of interest (V7, LOC) along with a control site (Cz). TMS over LOC produced results no different from TMS over baseline Cz (and prior no-TMS behavioral work). That is, depth sensitivity was higher for implausible versus plausible objects. Strikingly, TMS over V7 abolished differences in depth sensitivity for implausible versus plausible objects. V7 serves as a key locus in bringing stereosensitivity changes because of object context, perhaps by reweighing stereoscopic data en route to informing object–motoric interactions.

A New Distance Stereotest by Autostereoscopic Display Using an Eye-Tracking Method.

Objectives: This research aimed to present a novel glasses-free distance random-dot stereotest system (GFDRDSS) using an eye-tracking method. Methods: A single-view autostereoscopic display applying a backlight control system combined with an eye-tracking method and the corresponding random-dot stereotest software were developed to create a GFDRDSS with a viewing distance of 5 m. The stereoacuity of 12 subjects with normal eye position was evaluated using the Randot Stereotest, Stereoscopic Test Charts vol. 3 (Yan’s Charts), Distance Randot® Stereotest, and GFDRDSS. Results: The GFDRDSS could provide distinct and stable glasses-free stereoscopic perception even while the subject was moving their head. It could evaluate binocular disparities of 40–2,400 arcsec. Eleven subjects with normal near visual acuity had fine near stereovision (20–60 arcsec) using the Randot stereotest and Yan’s Charts. Under refractive correction, 10 subjects had fine stereovision (≤60 arcsec) using the GFDRDSS at a distance of 5 m, and 9 had fine stereovision using the Distance Randot® Stereotest at 3 m. Other subjects described the 100 arcsec-level stereograms correctly. The results exhibited a concordance of stereoacuity within one degrade between the two distance stereotests. Conclusion: The proposed GFDRDSS can alternately project a couple of random-dot stereograms to the subjects’ eyes and provide a glasses-free distance stereotest, which showed good concordance with the Distance Randot® Stereotest. More data are needed for statistical studies.

Electroencephalography Study of Frontal Lobe Evoked by Dynamic Random-Dot Stereogram.

PurposeThe purpose of this study was to investigate the cortical electrical activity and electroencephalography (EEG) features of the frontal lobe evoked by dynamic random dot stereogram (DRDS) and to probe the functional connectivity (FC) between the frontal lobe and occipital lobe when processing 3D perception based on the binocular disparity.MethodsThe EEG experiment involved 14 healthy adults with normal stereopsis (<60″) and normal corrected visual acuity (20/20). The Neuroscan system and 32-channel EEG cap were used to record EEG signals based on the DRDS stimuli. The maximum energies of 3 frequency bands (theta-/alpha- /beta-wave) from 13 interesting channels (FP1, FP2, F7, F3, FZ, F4, F8, FC3, FCZ, FC4, O1, OZ, and O2) located in the frontal and occipital lobes were calculated and analyzed. The FC between any two electrodes from the frontal and occipital lobes was calculated based on the Phase lag index (PLI).ResultsThe maximum powers of theta- and alpha-waves in most channels of the frontal and occipital lobes were significantly increased (P < 0.05) when the depth perception was evoked by DRDS above the threshold, compared with that without stereo vision. The changes in the maximum powers of both theta- and alpha-waves were significantly different among the 13 electrodes (P = 0.0004 and 0.0015, respectively). Tukey's multiple comparisons showed that the changes in the maximum powers of theta-wave were significantly different in F8 vs. O1, F8 vs. OZ, and F4 vs. O1 (P = 0.0186, 0.0444, and 0.0412, respectively). Moreover, the changes in the maximum powers of alpha-waves were significantly different in FP1 vs. O1 (P = 0.0182). The FCs of theta-waves between the frontal channels and the occipital channels were significantly enhanced when processing the depth perception, compared with those without stereopsis. There was no significant change in the FCs of the alpha-waves when having 3D perception except for FC between F8 and O1 and FC between F8 and OZ.ConclusionsThe cortical electrical activity in the frontal lobe and the functional connectivity between the frontal lobe and the occipital lobe increase when participating in the processing binocular disparity and obtaining 3D perception. Theta-waves in the frontal lobe may be crucial in the stereo vision.

Dynamics of absolute and relative disparity processing in human visual cortex

Cortical processing of binocular disparity is believed to begin in V1 where cells are sensitive to absolute disparity, followed by the extraction of relative disparity in higher visual areas. While much is known about the cortical distribution and spatial tuning of disparity-selective neurons, the relationship between their spatial and temporal properties is less well understood. Here, we use steady-state Visual Evoked Potentials and dynamic random dot stereograms to characterize the temporal dynamics of spatial mechanisms in human visual cortex that are primarily sensitive to either absolute or relative disparity. Stereograms alternated between disparate and non-disparate states at 2 Hz. By varying the disparity-defined spatial frequency content of the stereograms from a planar surface to corrugated ones, we biased responses towards absolute vs. relative disparities. Reliable Components Analysis was used to derive two dominant sources from the 128 channel EEG records. The first component (RC1) was maximal over the occipital pole. In RC1, first harmonic responses were sustained, tuned for corrugation frequency, and sensitive to the presence of disparity references, consistent with prior psychophysical sensitivity measurements. By contrast, the second harmonic, associated with transient processing, was not spatially tuned and was indifferent to references, consistent with it being generated by an absolute disparity mechanism. Thus, our results reveal a duplex coding strategy in the disparity domain, where relative disparities are computed via sustained mechanisms and absolute disparities are computed via transient mechanisms.

The effects of optically and digitally simulated aniseikonia on stereopsis.

PurposeTo simulate both lens‐induced and screen‐induced aniseikonia, and to assess its influence on stereopsis. Additionally, to determine if screen‐based size differences could neutralise the effects of lens‐induced aniseikonia.MethodA four‐circle (4‐C) paradigm was developed, where one circle appears in front or behind the others because of crossed or uncrossed disparity. This stereotest was used for three investigations: (1) Comparison with the McGill modified random dot stereogram (RDS), with anisometropia introduced with +2 D spheres and cylinders, and with aniseikonia introduced with 6% overall and 6% meridional (×180, ×90) magnifiers before the right eye; (2) Comparison of lens‐induced and screen‐induced 6% overall and meridional magnifications and (3) Determining if lens and screen effects neutralised, by opposing 6% lens‐induced magnification to the right eye with screen‐inducements of either 6% left eye magnification or 6% right eye minification. A pilot study of the effect of masking versus not masking the surround was also conducted.ResultsThe 4‐C test gave higher stereo‐thresholds than the RDS test by 0.5 ± 0.2 log units across both anisometropic and aniseikonic conditions. However, variations in power, meridian and magnification affected the two tests similarly. The pilot study indicated that surround masking improved neutralisation of screen and lens effects. With masking, lens‐induced and screen‐induced magnifications increased stereo‐thresholds similarly. With lens and screen effects opposed, for most participants stereo‐thresholds returned to baseline for overall and ×180 magnifications, but not for ×90 magnification. Only three of seven participants showed good compensation for ×90 magnification.ConclusionsEffects of lens‐induced aniseikonia on stereopsis cannot always be successfully simulated with a screen‐based method. The ability to neutralise refractive aniseikonia using a computer‐based method, which is the basis of digital clinical measurement, was reasonably successful for overall and ×180 meridional aniseikonia, but not very successful for ×90 aniseikonia.

Contributed Session III: Central-Peripheral Dichotomy (CPD) in feedforward and feedback processes explored by depth perception in random-dot stereograms (RDSs)

Information bottleneck limits feedforward signals from the primary visual cortex (V1) to higher brain areas, these signals nevertheless give initial perceptual hypotheses about visual scenes. Feedback from higher to lower visual areas verify and re-weight these hypotheses in noisy or ambiguous situations via analysis-by-synthesis. We call this process Feedforward-Feedback-Verify-reWeight (FFVW). CPD hypothesizes that the feedback is weaker or absent in the peripheral visual field (Zhaoping, 2017, 2019). Accordingly, peripheral vision is vulnerable to illusions by misleading V1 signals. CPD and FFVW are manifest using RDSs for depth surfaces by contrast-reversed random-dots (CRRDs), for which a black dot in one eye corresponds to a white dot in the other eye. V1 neurons respond to CRRDs as if their preferred binocular disparities become anti-preferred and vice versa, signalling reversed depths. I show that (1) the reversed depth is seen in peripheral but not central vision; (2) compromising feedback by brief viewing and backward masking makes reversed-depth seen in central vision; and (3) adding reversed-depth signals to normal-depth ones enhances or degrades depth percepts in central vision when these depth signals by V1 responses agree or disagree, respectively, with each other. In (3), degradation occurs only when the feedback is compromised, whereas enhancement occurs regardless, revealing a nonlinearity in the feedback processes for perceptual decisions.

Multiscale Temporal Self-Attention and Dynamical Graph Convolution Hybrid Network for EEG-Based Stereogram Recognition.

Stereopsis is the ability of human beings to get the 3D perception on real scenarios. The conventional stereopsis measurement is based on subjective judgment for stereograms, leading to be easily affected by personal consciousness. To alleviate the issue, in this paper, the EEG signals evoked by dynamic random dot stereograms (DRDS) are collected for stereogram recognition, which can help the ophthalmologists diagnose strabismus patients even without real-time communication. To classify the collected Electroencephalography (EEG) signals, a novel multi-scale temporal self-attention and dynamical graph convolution hybrid network (MTS-DGCHN) is proposed, including multi-scale temporal self-attention module, dynamical graph convolution module and classification module. Firstly, the multi-scale temporal self-attention module is employed to learn time continuity information, where the temporal self-attention block is designed to highlight the global importance of each time segments in one EEG trial, and the multi-scale convolution block is developed to further extract advanced temporal features in multiple receptive fields. Meanwhile, the dynamical graph convolution module is utilized to capture spatial functional relationships between different EEG electrodes, in which the adjacency matrix of each GCN layer is adaptively tuned to explore the optimal intrinsic relationship. Finally, the temporal and spatial features are fed into the classification module to obtain prediction results. Extensive experiments are conducted on collected datasets i.e., SRDA and SRDB, and the results demonstrate the proposed MTS-DGCHN achieves outstanding classification performance compared with the other methods. The datasets are available at https://github.com/YANGeeg/TJU-SRD-datasets and the code is at https://github.com/YANGeeg/MTS-DGCHN.

Neural responses to reflection symmetry for shapes defined by binocular disparity, and for shapes perceived as regions of background

Human perception of symmetry is associated with activation in an extended network of extrastriate visual areas. This activation generates an ERP called the Sustained Posterior Negativity (SPN). In most studies so far, the stimuli have been defined by luminance. We tested whether the SPN is present when stimuli are defined by stereoscopic disparity using random dot stereograms (RDS). In Experiment 1, we compared the SPN signal for contours specified by binocular disparity and contours specified by monocular cues. The SPN was equivalent, suggesting that the type of contour does not alter the SPN signal. In Experiment 2 we exploited the unique property of RDS to provide unambiguous figure-ground arrangements. Psychophysical work has shown that symmetry is more easily detected when it is a property of a single object (i.e., within a figure), compared to a property of a gap between two objects (i.e., the ground). Therefore, the target regions in this experiment could either be foreground or background. The SPN onset was delayed when the symmetry was in a ground region. This may be because object formation interferes with the processing of shape information in the ground region.

Associations Between Binocular Depth Perception and Performance Gains in Laparoscopic Skill Acquisition.

The ability to perceive differences in depth is important in many daily life situations. It is also of relevance in laparoscopic surgical procedures that require the extrapolation of three-dimensional visual information from two-dimensional planar images. Besides visual-motor coordination, laparoscopic skills and binocular depth perception are demanding visual tasks for which learning is important. This study explored potential relations between binocular depth perception and individual variations in performance gains during laparoscopic skill acquisition in medical students naïve of such procedures. Individual differences in perceptual learning of binocular depth discrimination when performing a random dot stereogram (RDS) task were measured as variations in the slope changes of the logistic disparity psychometric curves from the first to the last blocks of the experiment. The results showed that not only did the individuals differ in their depth discrimination; the extent with which this performance changed across blocks also differed substantially between individuals. Of note, individual differences in perceptual learning of depth discrimination are associated with performance gains from laparoscopic skill training, both with respect to movement speed and an efficiency score that considered both speed and precision. These results indicate that learning-related benefits for enhancing demanding visual processes are, in part, shared between these two tasks. Future studies that include a broader selection of task-varying monocular and binocular cues as well as visual-motor coordination are needed to further investigate potential mechanistic relations between depth perceptual learning and laparoscopic skill acquisition. A deeper understanding of these mechanisms would be important for applied research that aims at designing behavioral interventions for enhancing technology-assisted laparoscopic skills.

Relationship between the disparity tuning symmetry and responses to anti-correlated random dot stereograms in macaque areas V2, V3 and V3A

Relationship between the disparity tuning symmetry and responses to anti-correlated random dot stereograms in macaque areas V2, V3 and V3A

Ultra-High-Field Neuroimaging Reveals Fine-Scale Processing for 3D Perception.

Binocular disparity provides critical information about three-dimensional (3D) structures to support perception and action. In the past decade significant progress has been made in uncovering human brain areas engaged in the processing of binocular disparity signals. Yet, the fine-scale brain processing underlying 3D perception remains unknown. Here, we use ultra-high-field (7T) functional imaging at submillimeter resolution to examine fine-scale BOLD fMRI signals involved in 3D perception. In particular, we sought to interrogate the local circuitry involved in disparity processing by sampling fMRI responses at different positions relative to the cortical surface (i.e., across cortical depths corresponding to layers). We tested for representations related to 3D perception by presenting participants (male and female, N = 8) with stimuli that enable stable stereoscopic perception [i.e., correlated random dot stereograms (RDS)] versus those that do not (i.e., anticorrelated RDS). Using multivoxel pattern analysis (MVPA), we demonstrate cortical depth-specific representations in areas V3A and V7 as indicated by stronger pattern responses for correlated than for anticorrelated stimuli in upper rather than deeper layers. Examining informational connectivity, we find higher feedforward layer-to-layer connectivity for correlated than anticorrelated stimuli between V3A and V7. Further, we observe disparity-specific feedback from V3A to V1 and from V7 to V3A. Our findings provide evidence for the role of V3A as a key nexus for disparity processing, which is implicated in feedforward and feedback signals related to the perceptual estimation of 3D structures.SIGNIFICANCE STATEMENT Binocular vision plays a significant role in supporting our interactions with the surrounding environment. The fine-scale neural mechanisms that underlie the brain's skill in extracting 3D structures from binocular signals are poorly understood. Here, we capitalize on recent advances in ultra-high-field functional imaging to interrogate human brain circuits involved in 3D perception at submillimeter resolution. We provide evidence for the role of area V3A as a key nexus for disparity processing, which is implicated in feedforward and feedback signals related to the perceptual estimation of 3D structures from binocular signals. These fine-scale measurements help bridge the gap between animal neurophysiology and human fMRI studies investigating cross-scale circuits, from micro circuits to global brain networks for 3D perception.

The development of active binocular vision under normal and alternate rearing conditions.

The development of binocular vision is an active learning process comprising the development of disparity tuned neurons in visual cortex and the establishment of precise vergence control of the eyes. We present a computational model for the learning and self-calibration of active binocular vision based on the Active Efficient Coding framework, an extension of classic efficient coding ideas to active perception. Under normal rearing conditions with naturalistic input, the model develops disparity tuned neurons and precise vergence control, allowing it to correctly interpret random dot stereograms. Under altered rearing conditions modeled after neurophysiological experiments, the model qualitatively reproduces key experimental findings on changes in binocularity and disparity tuning. Furthermore, the model makes testable predictions regarding how altered rearing conditions impede the learning of precise vergence control. Finally, the model predicts a surprising new effect that impaired vergence control affects the statistics of orientation tuning in visual cortical neurons.

Contrast-reversed binocular dot-pairs in random-dot stereograms for depth perception in central visual field: Probing the dynamics of feedforward-feedback processes in visual inference

In a random-dot stereogram (RDS), the spatial disparities between the interocularly corresponding black and white random dots determine the depths of object surfaces. If a black dot in one monocular image corresponds to a white dot in the other, disparity-tuned neurons in primary visual cortex (V1) respond as if their preferred disparities become non-preferred and vice versa, reversing the disparity sign reported to higher visual areas. Reversed depth is perceptible in the peripheral but not the central visual field. This study demonstrates that, in central vision, adding contrast-reversed dots to a noisy RDS (containing the normal contrast-matched dots) can augment or degrade depth perception. Augmentation occurs when the reversed depth signals are congruent with the normal depth signals to report the same disparity sign, and occurs regardless of the viewing duration. Degradation occurs when the reversed and normal depth signals are incongruent with each other and when the RDS is viewed briefly. These phenomena reflect the Feedforward-Feedback-Verify-and-reWeight (FFVW) process for visual inference in central vision, and are consistent with the central-peripheral dichotomy that central vision has a stronger top-down feedback from higher to lower brain areas to disambiguate noisy and ambiguous inputs from V1. When a RDS is viewed too briefly for feedback, augmentation and degradation work by adding the reversed depth signals from contrast-reversed dots to the feedforward, normal, depth signals. With a sufficiently long viewing duration, the feedback vetoes incongruent reversed depth signals and amends or completes the imperfect, but congruent, reversed depth signals by analysis-by-synthesis computation.

Where there is no object formation, there is no perceptual organization: Evidence from the configural superiority effect

Object formation is considered the aim of perceptual organization, but such a proposition has been neglected in empirical studies. In the current study, we investigated the role of object formation in configural superiority. Essentially, discrimination on bar orientations was enhanced by adding a right angle to each of the bars. Such facilitation is due to the emergent feature (EF) of closure formed by combining the bars with right angles. To study object formation, visual stimuli were generated by random dot stereograms to form objects or holes in 3D. Behaviorally, we found that the EF of closure facilitated oddball discrimination on objects, as demonstrated by previous studies, but did not facilitate oddball discrimination on holes with the same shape as objects. Multivariate pattern analysis of functional magnetic resonance imaging (fMRI) data showed that the EF of closure increased the object classification accuracy compared to the holes in the lateral occipital cortex (LOC), where object information is encoded, but not in the early visual cortex (EVC). The neural representations of objects and holes with and without EFs were further investigated using representational similarity analysis. The results demonstrate that in the LOC, the neural representations of objects with EFs showed a greater difference than those of the other three, that is, objects without EFs and holes with or without EFs. However, the uniqueness of objects with EFs was not observed in the EVC. Thus, our results suggest that the EF of closure, which leads to the configural superiority effect, only emerges for objects but not for holes, and only in the LOC but not the EVC. Our study provides the first empirical evidence suggesting that object formation plays an indispensable role in perceptual organization.

On Stereoscopic Art.

Pictorial art is typically viewed with two eyes, but it is not binocular in the sense that it requires two eyes to appreciate the art. Two-dimensional representational art works allude to depth that they do not contain, and a variety of stratagems is enlisted to convey the impression that surfaces on the picture plane are at different distances from the viewer. With the invention of the stereoscope by Wheatstone in the 1830s, it was possible to produce two pictures with defined horizontal disparities between them to create a novel impression of depth. Stereoscopy and photography were made public at about the same time and their marriage was soon cemented; most stereoscopic art is now photographic. Wheatstone sought to examine stereoscopic depth without monocular pictorial cues. He was unable to do this, but it was achieved a century later by Julesz with random-dot stereograms The early history of non-photographic stereoscopic art is described as well as reference to some contemporary works. Novel stereograms employing a wider variety of carrier patterns than random dots are presented as anaglyphs; they show modulations of pictorial surface depths as well as inclusions within a binocular picture.

Unique Neural Activity Patterns Among Lower Order Cortices and Shared Patterns Among Higher Order Cortices During Processing of Similar Shapes With Different Stimulus Types.

We investigated the neural mechanism of the processing of three-dimensional (3D) shapes defined by disparity and perspective. We measured blood oxygenation level-dependent signals as participants viewed and classified 3D images of convex–concave shapes. According to the cue (disparity or perspective) and element type (random dots or black and white dotted lines), three types of stimuli were used: random dot stereogram, black and white dotted lines with perspective, and black and white dotted lines with binocular disparity. The blood oxygenation level-dependent images were then classified by multivoxel pattern analysis. To identify areas selective to shape, we assessed convex–concave classification accuracy with classifiers trained and tested using signals evoked by the same stimulus type (same cue and element type). To identify cortical regions with similar neural activity patterns regardless of stimulus type, we assessed the convex–concave classification accuracy of transfer classification in which classifiers were trained and tested using different stimulus types (different cues or element types). Classification accuracy using the same stimulus type was high in the early visual areas and subregions of the intraparietal sulcus (IPS), whereas transfer classification accuracy was high in the dorsal subregions of the IPS. These results indicate that the early visual areas process the specific features of stimuli, whereas the IPS regions perform more generalized processing of 3D shapes, independent of a specific stimulus type.

Восприятие виртуальных стереообъектов: особенности взаимодействия зрительных механизмов и пространственные перцептивные эффекты

The purpose of our study was investigation of the peculiarities of human visual perception in virtual environment created on the basis of stereo technologies. The participants were 100 adults aged from 17 to 79 years (40 males and 60 females, average age 32,9 years). Observation of virtual stereo objects was provided by computer software “Fusion” created for measuring visual fusion reserves which characterize the quality of binocular mechanisms of stereo perception. Test stimuli were random dot stereograms (RDSs) encoding a square test object moving from the screen to the observer. Separate presentation of the stimuli to the left and right eyes was based on the opposite circular polarization method. The participant’s task was to observe virtual stereo objects and describe perceived vi- sual images: their sizes, positions in depth and directions of movement. It has been found that, in conditions of view- ing the same virtual stereo objects, the participants with normally functioning mechanisms of binocular stereopsis could perceive quite different stereo images. On the basis of the perceived stereo image parameters, all participants were divided into four types. The described phenomena and the identified typology of spatial perceptual stereo effects could be considered as the consequences of restructuring interaction of visual sensory, accommodative and oculo-motor mechanisms involved in visible image formation when adapting to a virtual environment.

Surface slant impairs disparity discontinuity discrimination

Binocular disparity signals are highly informative about the three-dimensional structure of visual scenes, including aiding the detection of depth discontinuities between surfaces. Here, we examine factors affecting sensitivity to such surface discontinuities. Participants were presented with random dot stereograms depicting two planar surfaces slanted in opposite directions and were asked to judge the sign of the depth discontinuity created where those surfaces met. Although the judgement was focussed on the adjacent edges, the precision of depth discontinuity discrimination depended upon the slant of the two surfaces: increasing surface slants to ±60° increased discontinuity discrimination thresholds by, on average, a factor of 5. Control experiments examining discontinuity discrimination across surfaces with identical slants showed either biases in discontinuity judgements or reduced threshold elevation. These results suggest that sensitivity to depth discontinuities is affected by processing limitations in both local absolute disparity measurement mechanisms and mechanisms selective for disparity differences. As further evidence in support of this conclusion, we show that our results are well-described by a model of discontinuity discrimination based on the encoding of local differences in relative disparity.

Investigating the neural activity of various 3D visual fatigue degrees using depth‐related visual evoked potentials

AbstractSevere visual fatigue symptoms occur while users view three‐dimensional (3D) content. These symptoms adversely affect the user experience and hinder the widespread application of 3D media. Existing studies mainly used electroencephalography (EEG) power (based on frequency domain analysis) to evaluate 3D visual fatigue (3DVF), but their results were often contradictory and confusing. To address this problem, we investigated the relationship between EEG features and visual fatigue from the perspective of both time and time‐frequency domain. Random‐dot stereograms (RDS) with various disparities were employed to elicit depth‐related visual evoked potentials (VEPs). The experiment lasted about 27 min for each subject to induce fatigue, and the EEG was recorded synchronously. VEPs of different fatigue levels were processed to extract both time (such as P120 and N170 components in VEPs) and time‐frequency (like event‐related spectral perturbation [ERSP]) domain characteristics. A significant increase in P120 amplitude was observed in the parietal region, and time‐frequency analysis also revealed a significant ERSP decrease of theta bands in the central‐frontal region with a latency of 200 to 300 ms when subjects suffered fatigue. Our results confirm the hypothesis that activity of theta decreased with 3DVF level, or rather, we found ERSPs of theta bands on FC4 and Cz in the 200‐ to 300‐ms window decreased significantly across four fatigue levels. Furthermore, we first reported the relationship between P120 amplitude and 3DVF, which implied this feature could be considered as a feature of 3DVF evaluation. In summary, our studies could provide a new insight for 3DVF evaluation using EEG.

Neural representation of illusory reversed depth in anti-correlated random-dot stereograms across visual cortical areas in central and peripheral visual fields: An fMRI study

Neural representation of illusory reversed depth in anti-correlated random-dot stereograms across visual cortical areas in central and peripheral visual fields: An fMRI study