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Plaids consist of two orthogonally oriented gratings. However, their structure may be perceived as a checkerboard with an oblique orientation or as two overlaid gratings. We used a visual search paradigm to investigate how plaids with different perceived structures influence search efficiency for determining whether a preattentive plaid-specific or grating-specific mechanism is involved in representing the plaid. Participants searched for a grating among plaids (Experiment 1) or a plaid among gratings (Experiment 2). Contrast (low vs. high), composed spatial frequency (SF) of the plaid (coherent vs. mixed), and target-distractor orientation relationship (component orientation-aligned vs. structure orientation-aligned) were manipulated to vary the perceived structure of the plaid. Parallel search was observed when the target was a coherent checkerboard plaid, and orientation manipulation did not influence search efficiency. However, search performance was less efficient when the target plaid was perceived as overlaid gratings. When searching for a grating among plaids, low-SF gratings were located more quickly than high-SF gratings, regardless of the plaid distractor type. The results provide evidence for the existence of a preattentive plaid-specific mechanism that is distinct from the grating-sensitive mechanism. KEYWORDS visual search plaid feature integration grating

Visually-induced motion sickness (VIMS) remains an unsolved issue when using head-mounted displays (HMD) in immersive virtual reality (VR) systems. We investigate the influence of restricted visual field on sensorimotor incongruence of postural control in an immersive VR environment, as a surrogate marker of VIMS while standing steadily and viewing ambiguous optical-flow visual stimuli. Twenty-seven healthy participants wore HMD and viewed optical flow visual stimuli (called the plaid motion pattern) using a VR system. Visual stimuli were presented on a full-screen display, either only in the center or periphery of the visual field, or nowhere (Natural). To evaluate standing posture stability, we measured spatial (length and area of the center of the pressure (COP)) and temporal dynamics of body sway using a stabilometer. Subjective feelings of VIMS were assessed for each visual stimulus condition. The full-screen condition significantly worsened the COP measurements and feelings. The COP areas of standing balance under the center of the visual field condition were significantly smaller than those under the full-screen condition; however, the periphery of the visual field condition was comparable to the full-screen condition. The condition effects for the conditions (natural, center of the visual field, periphery of the visual field and full-screen) were observed in the COP measurements and subjective feelings. Optical-flow visual stimuli can induce body sway, suggesting sensorimotor incongruence in postural control. Ancillary findings demonstrated that subsequent to full-screen presentation, the periphery of the visual field potentially contributes to spatial and temporal dynamics of body sway and the sensorimotor incongruence rather than the central area.

Historically, yarn-dyed plaid fabrics (YDPFs) have enjoyed enduring popularity with many rich plaid patterns, but production data are still classified and searched only according to production parameters. The process does not satisfy the visual needs of sample order production, fabric design, and stock management. This study produced an image dataset for YDPFs, collected from 10,661 fabric samples. The authors believe that the dataset will have significant utility in further research into YDPFs. Convolutional neural networks, such as VGG, ResNet, and DenseNet, with different hyperparameter groups, seemed the most promising tools for the study. This paper reports on the authors’ exhaustive evaluation of the YDPF dataset. With an overall accuracy of 88.78%, CNNs proved to be effective in YDPF image classification. This was true even for the low accuracy of Windowpane fabrics, which often mistakenly includes the Prince of Wales pattern. Image classification of traditional patterns is also improved by utilizing the strip pooling model to extract local detail features and horizontal and vertical directions. The strip pooling model characterizes the horizontal and vertical crisscross patterns of YDPFs with considerable success. The proposed method using the strip pooling model (SPM) improves the classification performance on the YDPF dataset by 2.64% for ResNet18, by 3.66% for VGG16, and by 3.54% for DenseNet121. The results reveal that the SPM significantly improves YDPF classification accuracy and reduces the error rate of Windowpane patterns as well.

Converging evidence from human psychophysics and animal neurophysiology indicates that amblyopia is associated with abnormal function of area MT, a motion sensitive region of the extrastriate visual cortex. In this context, the recent finding that amblyopic eyes mediate normal perception of dynamic plaid stimuli was surprising, as neural processing and perception of plaids has been closely linked to MT function. One intriguing potential explanation for this discrepancy is that the amblyopic eye recruits alternative visual brain areas to support plaid perception. This is the hypothesis that we tested. We used functional magnetic resonance imaging (fMRI) to measure the response of the amblyopic visual cortex and thalamus to incoherent and coherent motion of plaid stimuli that were perceived normally by the amblyopic eye. We found a different pattern of responses within the visual cortex when plaids were viewed by amblyopic as opposed to non-amblyopic eyes. The non-amblyopic eyes of amblyopes and control eyes differentially activated the hMT+ complex when viewing incoherent vs. coherent plaid motion, consistent with the notion that this region is centrally involved in plaid perception. However, for amblyopic eye viewing, hMT+ activation did not vary reliably with motion type. In a sub-set of our participants with amblyopia we were able to localize MT and MST within the larger hMT+ complex and found a lack of plaid motion selectivity in both sub-regions. The response of the pulvinar and ventral V3 to plaid stimuli also differed under amblyopic vs. non-amblyopic eye viewing conditions, however the response of these areas did vary according to motion type. These results indicate that while the perception of the plaid stimuli was constant for both amblyopic and non-amblyopic viewing, the network of neural areas that supported this perception was different.

Integrating local motion signals detected by the primary motion detector is crucial for representing a rigid, two-dimensional motion. The nature of motion integration has been studied using stimuli consisting of two superimposed sinusoidal gratings of different orientations, called plaid motion, and it has been shown that humans perceive integrated motion in the direction where the component constraint lines are intersected. We previously found that pigeons and humans perceive different movement directions from plaid motion; pigeons responded to the vector average direction of the gratings. Although this suggests that the underlying processes of motion integration differ between the two species, the viewing distance in the pigeon experiment, which used a touch panel procedure, was much smaller than in typical human experiments. The current study investigated the potential effect of viewing distance on the perception of plaid motion in pigeons. We trained six pigeons to detect whether motion directions were tilted leftward or rightward while a visual display was presented 0 or 40 cm from an operant chamber. The pigeons responded to plaid stimuli for both viewing distance conditions as if they perceived motion in the vector average direction of two-component gratings. The result indicates that the species difference in plaid perception is not an artefact of viewing distance and suggests that pigeons use a different strategy than humans for integrating visual motion.

We suggest PLAID, APLAID, and FCAS3 have to be considered as different aspects of the same underlying condition, because of our long‐term clinical and genetical experiences. Some CVID patients have the same disease‐causing mutations in PLCG2 gene, so it may be better to define all of them as “PLCG2deficiency.” Germline mutations in PLCG2 gene cause PLAID, APLAID, FCAS3, and CVID. Clinical experiences in patients with PLCG2 mutations led us to consider that they are different aspects of the same underlying condition.

Auditory streaming and visual plaids have been used extensively to study perceptual organization in each modality. Both stimuli can produce bistable alternations between grouped (one object) and split (two objects) interpretations. They also share two peculiar features: (i) at the onset of stimulus presentation, organization starts with a systematic bias towards the grouped interpretation; (ii) this first percept has ‘inertia’; it lasts longer than the subsequent ones. As a result, the probability of forming different objects builds up over time, a landmark of both behavioural and neurophysiological data on auditory streaming. Here we show that first percept bias and inertia are independent. In plaid perception, inertia is due to a depth ordering ambiguity in the transparent (split) interpretation that makes plaid perception tristable rather than bistable: experimental manipulations removing the depth ambiguity suppressed inertia. However, the first percept bias persisted. We attempted a similar manipulation for auditory streaming by introducing level differences between streams, to bias which stream would appear in the perceptual foreground. Here both inertia and first percept bias persisted. We thus argue that the critical common feature of the onset of perceptual organization is the grouping bias, which may be related to the transition from temporally/spatially local to temporally/spatially global computation.

In this challenging work, Wales's most prominent political commentator assesses the truth of the historical charges that senior figures among Welsh nationalists were sympathetic towards Fascism during the 1930s and the Second World War.

When observers view a perceptually bistable stimulus, their perception changes stochastically. Various studies have shown across-observer correlations in the percept durations for different bistable stimuli including binocular rivalry stimuli and bistable moving plaids. Previous work on binocular rivalry posits that neural inhibition in the visual hierarchy is a factor involved in the perceptual fluctuations in that paradigm. Here, in order to investigate whether between-observer variability in cortical inhibition underlies correlated percept durations between binocular rivalry and bistable moving plaid perception, we used center-surround suppression as a behavioral measure of cortical inhibition. We recruited 217 participants in a test battery that included bistable perception paradigms as well as a center-surround suppression paradigm. While we were able to successfully replicate the correlations between binocular rivalry and bistable moving plaid perception, we did not find a correlation between center-surround suppression strength and percept durations for any form of bistable perception. Moreover, the results from a mediation analysis indicate that center-surround suppression is not the mediating factor in the correlation between binocular rivalry and bistable moving plaids. These results do not support the idea that cortical inhibition can explain the between-observer correlation in mean percept duration between binocular rivalry and bistable moving plaid perception.