Visual Perceptual Processing Research Articles

Comparing the Effects of Two Education-Based Intervention Programs on Visual Perception Processes of Children with Developmental Dyslexia

ABSTRACT Investigating the effects of the special education support program (SESP) and visual-praxis-based occupational therapy program (VPBOTP) on visual perception skills of children with developmental dyslexia (DD). A time-series quasi-experimental design with two stages was used. The first stage included visual perception assessments of children with DD who were registered to the SESP, using MVPT-3. Following the assessments, SESP was implemented for a total of 16 hours in the span of 8 weeks. In the second stage, MVPT-3 was administered for a second time, SESP’s implementation continued for another 16 hours and VPBOTP was implemented also for a total of 32 hours in the span of 8 weeks. Finally, the MVPT-3 was administered for the third time. VPBOTP was found to be statistically more effective than SESP in improving visual perception skills (p<0.05). VPBOTP offers a different, individualizable, and flexible approach for improving visual perception skills of children with DD and its usage can be widened to other populations.

Ocular fixations modulate audiovisual semantic congruency when standing in an upright position

Introduction: Multisensory audiovisual semantic congruency is the process by which visual information is perceived as integrated to auditory stimuli, because both coincide in terms of simultaneity and semantic correspondence. This study was aimed at establishing whether visual percepts, which semantically correspond to auditory stimuli, are associated with ocular fixations in modulating bottom-up areas while keeping a body posture alignment between the up-direction and the idiotropic axes, as well as in another orientation corresponding to a vectorial opposition between the up-direction and the head idiotropic axis. Method: Two groups (one for each position) were selected from a sample of 88 people. A bistable image was presented on a screen of a fixed 120 Hz eye-tracker device, providing background auditory stimuli so as to establish semantic congruencies and their relations to ocular fixations. Results: It was found that audiovisual semantic congruency is associated with fixations when idiotropic vectors are aligned with the up direction. Fixations manifested in bottom-up modulating areas are not associated with multisensory audiovisual semantic congruency when the head idiotropic vector is parallel with the gravity vector. Eye fixations decrease significantly if the head idiotropic axis is aligned with the gravity vector. Conclusion: It is concluded that body position can affect visual perceptual processes involved in the occurrence of semantic congruency.

Visual Attention to Cued Targets in Simulated Aided Augmentative and Alternative Communication Displays for Individuals With Intellectual and Developmental Disabilities

Purpose Many aided augmentative and alternative communication (AAC) systems require the use of an external display that is represented via a visual modality. It is critical to evaluate and understand visual–perceptual processing in individuals with disabilities who could benefit from AAC. One way to evaluate how individuals process visual materials is through research-based automated eye-tracking technologies that obtain a fine-grained stream of data concerning gaze paths of visual attention. Method The current study examined how individuals with autism spectrum disorder ( n = 13), Down syndrome ( n = 13), intellectual and developmental disabilities ( n = 9), or typical development ( n = 20) responded to a spoken prompt to find a thumbnail-sized navigation key within a complex AAC display, including a main visual scene display (VSD) and a navigation bar of four thumbnail-sized VSDs. Stimuli were presented on a monitor containing automated eye-tracking research technology that recorded patterns of visual attention. Results Participants across groups spent more time fixating on a target thumbnail VSD navigation image after the presentation of the spoken cue to look at the target, compared to before the presentation of the spoken cue; they also spent more time looking at the target thumbnail VSD than the other thumbnail-sized VSDs in the navigation bar after the cue. Discussion Participants were able to locate the target thumbnail VSDs, even within the context of a visually complex AAC display. Implications for the design of AAC displays and for assessment of comprehension are discussed.

Visual Perception and Visuomotor Reaction Speed Are Independent of the Individual Alpha Frequency.

While the resting-state individual alpha frequency (IAF) is related to the cognitive performance and temporal resolution of visual perception, it remains unclear how it affects the neural correlates of visual perception and reaction processes. This study aimed to unravel the relation between IAF, visual perception, and visuomotor reaction time. One hundred forty-eight (148) participants (28 non-athletes, 39 table tennis players, and 81 badminton players) investigated in three previous studies were considered. During a visuomotor reaction task, the visuomotor reaction time (VMRT) and EMG onset were determined. In addition, a 64-channel EEG system identified the N2, N2-r, and BA6 negativity potentials representing the visual and motor processes related to visuomotor reactions. Resting-state individual alpha frequency (IAF) in visual and motor regions was compared based on sport experience (athletes vs. non-athletes), discipline (badminton vs. table tennis), and reaction performance (fast vs. medium vs. slow reaction time). Further, the differences in the IAF were determined in relation to the speed of neural visual (high vs. medium vs. low N2/N2-r latency) and motor (high vs. medium vs. low BA6 negativity latency). Group comparisons did not reveal any difference in the IAF between athletes and non-athletes (p = 0.352, ηp2 = 0.02) or badminton and table tennis players (p = 0.221, ηp2 = 0.02). Similarly, classification based on the behavioral or neural performance indicators did not reveal any effects on the IAF (p ≥ 0.158, ηp2 ≤ 0.027). IAF was not correlated to any of the behavioral or neural parameters (r ≤ 0.10, p ≥ 0.221). In contrast to behavioral results on cognitive performance and visual temporal resolution, the resting state IAF seemed unrelated to the visual perception and visuomotor reaction speed in simple reaction tasks. Considering the previous results on the correlations between the IAF, cognitive abilities, and temporal sampling of visual information, the results suggest that a higher IAF may facilitate the amount and frequency but not the speed of information transfer.

Productivity of the performance of visual perceptual tasks and symptom severity in patients with schizotypal disorder

IntroductionThe experimental research of visual perceptual processes in schizophrenia could shed a light on the psychological mechanisms of development of the illness.ObjectivesTo research the performance of visual perceptual tasks and its correlation with the symptom severity in patients with schizotypal disorder (SD).Methods40 patients with SD in ICD-10 (mean age 29.8±8.3 years) were enrolled to the study. The Positive and Negative Symptoms Scale (PANSS) and two series of visual-perceptual tasks (Figures of Witkin and Goldstein) were applied. In series I subject should make a decision whether a complex figure contains a simple one without any feedback from the experimenter (all 96 trials). In series II each trial included two complex figures presented simultaneously (all 96 trials) that increased the visual-perceptual load. Statistical significance was ascertained by Spearman’s rank correlation.ResultsNegative correlations were established between the number of right answers in series II of visual perceptual tasks and emotional withdrawal (r=-0.78, p≤0.01), passive/apathetic social withdrawal (r=-0.53, p≤0.05). Time of performance of series I and series II had negative correlations with preoccupation (r=-0.55 and r=-0.53, p≤0.05, respectively).ConclusionsThe decrease in the productivity of visual perceptual tasks performance in case of additional load relates with reduced social and emotional dimensions of symptoms (social initiation, passivity, lack of sociality and inattention in daily activity, etc.) of patients with SD. Impulsivity in solutions (reduction of decision-making time) is associated with the increase of preoccupation with feelings, thoughts and autistic fantasies that lead to social and daily life disadaptation.

Visual perception of different wood surfaces: an event-related potentials study

Visual perception of the appearances of different wood surfaces is greatly influenced by their features, such as color, grain, and gloss. Among these features, human visual perception of wood grain type occurs through a later and higher-ordered cognitive process than the perception of color or gloss. Dark wood was subjectively preferred to light- or medium-colored wood, and both matte and glossy wood were preferred to semigloss wood. Understanding how the appearance of wood is processed in visual perception is critical for wood product design and will help improve consumer satisfaction. Unlike traditional subjective evaluation, neuroscientific methods enable a quantitative understanding of the process and are sensitive to the human visual perceptual response to the appearance of wood surfaces. The objectives of this study were to quantify the visual perception process and to explore the human neural activity elicited by different wood surface appearances. Three types of wood differing in color (light, medium, and dark) were cut to expose two different grain types (radial and tangential) and finished to three different gloss values (matte, semigloss, and glossy); digital images of these stimuli were shown to the subjects on a screen. A subjective emotion scale was constructed to measure their subjective evaluation, and neural ERP (event-related potential) data reflecting subjects’ early visual perception were recorded. Finally, all the data underwent analysis of variance as well as correlation analysis. Regarding early visual perception, the measurements of relevant ERP components showed that subjects perceived the color and gloss of wood more quickly than the grain type, and their perception of wood grain involved a higher-order cognitive process. The match or mismatch between a given stimulus and a subject’s visual memory of wood surface appearance could enhance different ERP components, respectively. In addition, subjects had significantly greater appreciation for dark wood than for other colors, and semigloss wood was less favored than matte or glossy wood. This study provides an objective method to measure the visual perceptual processing of wood appearance; this method may help improve the efficiency of material selection for wood product design. Furthermore, the quantification method can be used by designers in measuring their wood products, and the results can be treated as indicators by which to evaluate the appearance of wood.

Predicting future poor readers from pre-reading visual skills: A longitudinal study

Reading is essential for learning, from literature to physics, from paper to screens on e-readers and smart phones. Even if it is well known that learning to read implies good language skills, children also need to develop good oculomotor and visual-perception skills. Thereby, any deficits in visual processing may affect learning. The possible impact of visual deficits is rarely considered, especially with regard to eye movements and visual perception. Hence, these deficits are usually discovered much later or remain undiagnosed. The present study aimed at assessing the usefulness of visual processing related measures in the early detection of reading difficulties. Visual skill differences that are apparent early in kindergarten might provide predictive insights into risk for learning difficulties at school entry. We used a prospective, longitudinal approach where visual processes (assessed with the Developmental Eye Movement (DEM) test) were measured in 51 preschoolers, and the impact of these processes on future reading development was explored one year later, in Grade 1. Results showed that (1) 31% of our sample of preschoolers showed visual processing impairments (without any clinical complaints) and (2) reading accuracy and speed in first graders were significantly correlated with visual skills assessed in kindergarten, thus confirming the significant role of oculomotor and visual-perception processes in the acquisition of reading skills. These suggests the potential for these measures to be used clinically for identifying children at risk for low academic achievement, enabling appropriate targeting of early interventions.

The influence of social context and social connection on visual perceptual processes

The aim of this study was twofold: (1) to re-test whether a minimal social context has an influence on gaze patterns, and (2) to determine if a social connection (i.e., friendship) has a modulatory effect on gaze patterns in a minimal social context. In Experiment 1, two unacquainted participants were paired and seated at separate testing stations in the same room. At the beginning of each trial, participants were informed whether they were looking at different image sets (solo trials), or the same image set (joint trials). Image sets consisted of a positive, a negative, and two neutral images. No explicit task instructions were provided and there was no interaction between participants during the task. Experiment 2 was identical to Experiment 1, except that participants were paired with a friend. The fixation-based metrics of interest were time to first fixation (TFF) and total fixation duration (TFD). The findings revealed that social context has a modulatory effect on attentional capture (i.e., TFF) irrespective of social connection. Unexpectedly, a negativity bias was found to hold attention (i.e., TFD) regardless of social context. However, having a social connection did increase the time spent looking at positive images on the joint trials. Having a social connection with another person seems to alter looking behaviour such that more time is spent looking at positive images on the joint trials compared to the solo trials. These findings highlight the importance of evaluating both TFD and TFF to develop a better understanding of the factors underlying joint perception.

The mind’s magic lantern: David Brewster and the scientific imagination

ABSTRACT The imagination has always been thought to operate primarily in conjunction with the sense of vision, imagined objects and scenes being conjured up before the ‘mind’s eye’. In early nineteenth-century Scotland the natural philosopher David Brewster developed a theory of the imagination that explained its operation through a reversal of the normal processes of visual perception. These ideas were rooted in the mental philosophy of the eighteenth-century Scottish Enlightenment. For Brewster the mind’s eye was also the eye of the body, and images from the memory and imagination were projected onto the retina in the same manner that images were projected onto the screen in a magic lantern show. This theory underpinned his belief that imagination played an essential role in scientific discovery. Brewster believed that this process was as essential to the discoveries of science as it was to the creation of great poetry. The writings of Brewster can tell us a great deal about the connections between science and literature in the early nineteenth century, as well as showing that the philosophy of science in contemporary Britain was far from monolithic.

Early Visual Processing and Perception Processes in Object Discrimination Learning.

A brief image presentation is sufficient to discriminate and individuate objects of expertise. Although perceptual expertise is acquired through extensive practice that increases the resolution of representations and reduces the latency of image decoding and coarse and fine information extraction, it is not known how the stages of visual processing impact object discrimination learning (ODL). Here, we compared object discrimination with brief (100 ms) and long (1,000 ms) perceptual encoding times to test if the early and late visual processes are required for ODL. Moreover, we evaluated whether encoding time and discrimination practice shape perception and recognition memory processes during ODL. During practice of a sequential matching task with initially unfamiliar complex stimuli, we find greater discrimination with greater encoding times regardless of the extent of practice, suggesting that the fine information extraction during late visual processing is necessary for discrimination. Interestingly, the overall discrimination learning was similar for brief and long stimuli, suggesting that early stages of visual processing are sufficient for ODL. In addition, discrimination practice enhances perceive and know for brief and long stimuli and both processes are associated with performance, suggesting that early stage information extraction is sufficient for modulating the perceptual processes, likely reflecting an increase in the resolution of the representations and an early availability of information. Conversely, practice elicited an increase of familiarity which was not associated with discrimination sensitivity, revealing the acquisition of a general recognition memory. Finally, the recall is likely enhanced by practice and is associated with discrimination sensitivity for long encoding times, suggesting the engagement of recognition memory in a practice independent manner. These findings contribute to unveiling the function of early stages of visual processing in ODL, and provide evidence on the modulation of the perception and recognition memory processes during discrimination practice and its relationship with ODL and perceptual expertise acquisition.

Differential Circuit Mechanisms of Young and Aged Visual Cortex in the Mammalian Brain

The main goal of this review is to summarize and discuss (1) age-dependent structural reorganization of mammalian visual cortical circuits underlying complex visual behavior functions in primary visual cortex (V1) and multiple extrastriate visual areas, and (2) current evidence supporting the notion of compensatory mechanisms in aged visual circuits as well as the use of rehabilitative therapy for the recovery of neural plasticity in normal and diseased aging visual circuit mechanisms in different species. It is well known that aging significantly modulates both the structural and physiological properties of visual cortical neurons in V1 and other visual cortical areas in various species. Compensatory aged neural mechanisms correlate with the complexity of visual functions; however, they do not always result in major circuit alterations resulting in age-dependent decline in performance of a visual task or neurodegenerative disorders. Computational load and neural processing gradually increase with age, and the complexity of compensatory mechanisms correlates with the intricacy of higher form visual perceptions that are more evident in higher-order visual areas. It is particularly interesting to note that the visual perceptual processing of certain visual behavior functions does not change with age. This review aims to comprehensively discuss the effect of normal aging on neuroanatomical alterations that underlie critical visual functions and more importantly to highlight differences between compensatory mechanisms in aged neural circuits and neural processes related to visual disorders. This type of approach will further enhance our understanding of inter-areal and cortico-cortical connectivity of visual circuits in normal aging and identify major circuit alterations that occur in different visual deficits, thus facilitating the design and evaluation of potential rehabilitation therapies as well as the assessment of the extent of their rejuvenation.

The threshold and semantic characteristics of fast transient visual-perceptive processes in patients with affective disorders

The article is devoted to the currently topical problem of modern medical psychology, namely the study of conscious and unconscious perceptual-information processes in patients with affective disorders. The aim of the work was to determine the thresholds and semantic components of visual perception in patients with various forms of affective disorders. The latest method of ultrafast (tachistoscopic) demonstration of visual verbal stimuli was used to examine 23 patients with depression and anxiety-depressive disorders. The obtained results are compared with similar indicants of the control group, which consisted of 15 mentally healthy individuals, and analyzed using Student's criterion, one-way and multifactor models of analysis of variance. It has been shown that in the presence of an affective disorder, the threshold exposure time required for reliable identification of visual verbal stimuli is on average more than three times higher, i.e. is much worse than a similar perceptual threshold in individuals without mental disorders. Thus, in affective disorders there is inhibition and suppression of not only emotional and psychomotor, but visual-perceptual processes as well. It is proved that the time thresholds of visual perception significantly depend not only on the presence of emotional disorders, but also on their psychopathological structure, as well as on the age factor. In depressed patients, visual-perceptual disorders are much more pronounced than in patients with anxiety-depressive disorders, namely: in depression, the minimal absolute sensory thresholds are significantly higher, more attempts are made to adapt the visual analyzer, and this deficit is significantly increased depending on age. In patients with depressive and anxiety-depressive disorders also revealed significant features of psychosemantic components of the mechanisms of recognition of verbal stimuli, which consists in a kind of unconscious filtering of the latter with a predominant perception of words with negative emotional loading. The obtained results might be meaningful in the process of developing the new diagnostic methods for affective disorders and in creating the personalized psycho-correctional programs based on the methodological principles of subsensory stimulation.

Positive influence of certain sports on learning and second language acquisition processes

Various research convincingly demonstrated positive influence of certain sports and physical exercises on brain and brain functions in general, and on cognitive functions in particular. As it has been demonstrated, efficient and well-developed cognitive functions enhance all human activities and are of crucial importance for learning. In particular, this paper focuses on the positive correlation between certain sports and language learning and its relevance to the Second Language Acquisition studies (SLA). In SLA, students' ability to process input strongly depends on their cognitive abilities, namely, their abilities to process audio and visual input. As various researchers demonstrated, some sports enhance sportsmen's abilities of audio and visual perception; these developed cognitive abilities may, in turn, enhance SLA process. The paper analyses some data collected during the experiments with three groups of students, age 20-23: basketball players, judo wrestlers and control group whose members practiced sports only 2h/week. Three groups were exposed to three types of stimuli: (reverse chess pattern, tone click, flash of light); their brain activity was monitored by EEG. The obtained results demonstrated that basketball players manifested better-developed cognitive abilities responsible for the perception of audio and video stimuli. They were also faster in making decisions on the basis of the video/audio stimuli perceived. Similar results were obtained by American psychologists (University of Illinois, Urbana-Champaign). Their study involved 87 Brazilian volleyball players and 67 persons who don't practice sports. The results were published in Frontiers in Psychology. Experiments have shown that athletes are usually better in controlling their reactions and are able to slow down their reactions, if necessary. According to the professor of Psychology Arthur Kramer, one of the authors of the research, "Athletes can perceive information faster and switch quicker between different tasks than those who don't practice sports." During the experiment, all the participants were asked to perform tasks to test their cognitive abilities (information perception, memory, reactions). The most interesting discovery was that the athletes had significant cognitive advantages over women and men who had not practiced sports. Volleyball players were faster in reactions, in noticing differences in the pictures, in identifying the missing details in puzzles. The process of auditory and visual perception and processing involves many neural structures: from primary units of signal processing sensors to higher levels of processing, responsible for stimuli recognition and decision-making. As it is known, individual waves of cognitive evoked potentials reflect the involvement of certain neural mechanisms of visual and auditory systems in processing and recognition of stimuli of corresponding modality. Wave characteristics can indirectly indicate working speed of specific units of the neural circuit and the number of neurons involved; it may allow measuring the influence of various sports training loads on the development of neural chains involved in audio/video stimuli perception, processing and decision-making. These aspects are also considered important for input processing in SLA. The paper analyses positive contribution of certain sports to learning in general, and Second Language Acquisition in particular, using neuroscience, psychological and socio-cultural approaches.

Person Re-Identification via Attention Pyramid.

In this paper, we propose an attention pyramid method for person re-identification. Unlike conventional attention-based methods which only learn a global attention map, our attention pyramid exploits the attention regions in a multi-scale manner because human attention varies with different scales. Our attention pyramid imitates the process of human visual perception which tends to notice the foreground person over the cluttered background, and further focus on the specific color of the shirt with close observation. Specifically, we describe our attention pyramid by a "split-attend-merge-stack" principle. We first split the features into multiple local parts and learn the corresponding attentions. Then, we merge local attentions and stack these merged attentions with the residual connection as an attention pyramid. The proposed attention pyramid is a lightweight plug-and-play module that can be applied to off-the-shelf models. We implement our attention pyramid method in two different attention mechanisms including: channel-wise attention and spatial attention. We evaluate our method on four large-scale person re-identification benchmarks including Market-1501, DukeMTMC, CUHK03, and MSMT17. Experimental results demonstrate the superiority of our method, which outperforms the state-of-the-art methods by a large margin with limited computationa cost. Code is available at https://github.com/CHENGY12/APNet.

Multi-Sensor Image Fusion: A Survey of the State of the Art

Image fusion has been developing into an important area of research. In remote sensing, the use of the same image sensor in different working modes, or different image sensors, can provide reinforcing or complementary information. Therefore, it is highly valuable to fuse outputs from multiple sensors (or the same sensor in different working modes) to improve the overall performance of the remote images, which are very useful for human visual perception and image processing task. Accordingly, in this paper, we first provide a comprehensive survey of the state of the art of multi-sensor image fusion methods in terms of three aspects: pixel-level fusion, feature-level fusion and decision-level fusion. An overview of existing fusion strategies is then introduced, after which the existing fusion quality measures are summarized. Finally, this review analyzes the development trends in fusion algorithms that may attract researchers to further explore the research in this field.

The Performance of Visual Perceptual Tasks in Patients with Schizotypal Personality Disorder.

The most significant features for clinical diagnosis of schizotypal personality disorder (SPD) are cognitive-perceptual and disorganized symptoms. Experimental study of visual perceptual processes is important to elucidate the psychological mechanisms of cognitive-perceptual impairment in SPD. To research the performance of visual perceptual tasks in SPD. Series I and II presented the subjects with visual perceptual tasks with different types of instructions (vague, verbal, or visual perceptual cues). The Wechsler Adult Intelligence Scale (WAIS-R) was also administered. The participants were 39 SPD patients, 36 obsessive-compulsive personality disorder (OCPD) patients (F.21.8, F.60.5 in ICD-10, respectively), and 102 healthy controls. SPD patients had a significantly lower number of correct answers in conditions of vague instruction and verbal cues in Series I of a visual-perceptual task in comparison with healthy subjects (p < 0.01). With visual perceptual cues in Series II, patients with SPD had the same number of correct answers as controls, whereas OCPD patients had the same number of correct answers as controls with verbal cues in Series I. SPD patients had significantly lower scores in most verbal and nonverbal WAIS-R subtests in comparison with controls. SPD patients differed from OCPD patients in that they had lower scores in the "Information" (p < 0.05) and "Comprehension" (p < 0.05) subtests. With visual-perceptual cues, SPD patients were able to achieve normative results in the performance of visual-perceptual tasks, whereas patients with OCPD demonstrated lower productivity. In SPD patients, the basic impairments were associated with difficulties in inhibition of peculiar responses, stability of a subjective manner of performance and inability to revise it, low orientation to the model, and slipping into subjective associations with the stimuli.

The Performance of Visual Perceptual Tasks in Patients with Schizotypal Personality Disorder

Background. The most significant features for clinical diagnosis of schizotypal personality disorder (SPD) are cognitive-perceptual and disorganized symptoms. Experimental study of visual perceptual processes is important to elucidate the psychological mechanisms of cognitive-perceptual impairment in SPD. Objective. To research the performance of visual perceptual tasks in SPD. Design. Series I and II presented the subjects with visual perceptual tasks with different types of instructions (vague, verbal, or visual perceptual cues). The Wechsler Adult Intelligence Scale (WAIS-R) was also administered. The participants were 39 SPD patients, 36 obsessive-compulsive personality disorder (OCPD) patients (F.21.8, F.60.5 in ICD-10, respectively), and 102 healthy controls. Results. SPD patients had a significantly lower number of correct answers in conditions of vague instruction and verbal cues in Series I of a visual-perceptual task in comparison with healthy subjects (р ≤ 0.01). With visual perceptual cues in Series II, patients with SPD had the same number of correct answers as controls, whereas OCPD patients had the same number of correct answers as controls with verbal cues in Series I. SPD patients had significantly lower scores in most verbal and nonverbal WAIS-R subtests in comparison with controls. SPD patients differed from OCPD patients in that they had lower scores in the “Information” (p ≤ 0.05) and “Comprehension” (p ≤ 0.05) subtests. Conclusion. With visual-perceptual cues, SPD patients were able to achieve normative results in the performance of visual-perceptual tasks, whereas patients with OCPD demonstrated lower productivity. In SPD patients, the basic impairments were associated with difficulties in inhibition of peculiar responses, stability of a subjective manner of performance and inability to revise it, low orientation to the model, and slipping into subjective associations with the stimuli.

Anodal Occipital Transcranial Direct Current Stimulation Enhances Perceived Visual Size Illusions.

Human early visual cortex has long been suggested to play a crucial role in context-dependent visual size perception through either lateral interaction or feedback projections from higher to lower visual areas. We investigated the causal contribution of early visual cortex to context-dependent visual size perception using the technique of transcranial direct current stimulation and two well-known size illusions (i.e., the Ebbinghaus and Ponzo illusions) and further elucidated the underlying mechanism that mediates the effect of transcranial direct current stimulation over early visual cortex. The results showed that the magnitudes of both size illusions were significantly increased by anodal stimulation relative to sham stimulation but left unaltered by cathodal stimulation. Moreover, the anodal effect persisted even when the central target and surrounding inducers of the Ebbinghaus configuration were presented to different eyes, with the effect lasting no more than 15 min. These findings provide compelling evidence that anodal occipital stimulation enhances the perceived visual size illusions, which is possibly mediated by weakening the suppressive function of the feedback connections from higher to lower visual areas. Moreover, the current study provides further support for the causal role of early visual cortex in the neural processing of context-dependent visual size perception.

EEG-based Identification of Evidence Accumulation Stages in Decision-Making.

Dating back to the 19th century, the discovery of processing stages has been of great interest to researchers in cognitive science. The goal of this paper is to demonstrate the validity of a recently developed method, hidden semi-Markov model multivariate pattern analysis (HsMM-MVPA), for discovering stages directly from EEG data, in contrast to classical reaction-time-based methods. To test the validity of stages discovered with the HsMM-MVPA method, we applied it to two relatively simple tasks where the interpretation of processing stages is straightforward. In these visual discrimination EEG data experiments, perceptual processing and decision difficulty were manipulated. The HsMM-MVPA revealed that participants progressed through five cognitive processing stages while performing these tasks. The brain activation of one of those stages was dependent on perceptual processing, whereas the brain activation and the duration of two other stages were dependent on decision difficulty. In addition, evidence accumulation models (EAMs) were used to assess to what extent the results of HsMM-MVPA are comparable to standard reaction-time-based methods. Consistent with the HsMM-MVPA results, EAMs showed that nondecision time varied with perceptual difficulty and drift rate varied with decision difficulty. Moreover, nondecision and decision time of the EAMs correlated highly with the first two and last three stages of the HsMM-MVPA, respectively, indicating that the HsMM-MVPA gives a more detailed description of stages discovered with this more classical method. The results demonstrate that cognitive stages can be robustly inferred with the HsMM-MVPA.

Altered Intrinsic and Casual Functional Connectivities of the Middle Temporal Visual Motion Area Subregions in Chess Experts.

An outstanding chess player needs to accumulate massive visual and spatial information for chess configurations. Visual motion area (MT) is considered as a brain region specialized for visual motion perception and visuospatial attention processing. However, how long-term chess training shapes the functional connectivity patterns of MT, especially its functional subregions, has rarely been investigated. In our study, using resting-state functional connectivity (RSFC) and Granger causality analysis (GCA), we studied the changed functional couplings of MT subregions between 28 chess master players and 27 gender- and age-matched healthy novices to reveal the neural basis of long-term professional chess training. RSFC analysis identified decreased functional connections between right dorsal-anterior subregion (CI1.R) and left angular gyrus, and increased functional connections between right ventral-anterior MT subregion (CI2.R) and right superior temporal gyrus in chess experts. Moreover, GCA analyses further found increased mutual interactions of left angular gyrus and CI1.R in chess experts compared to novice players. These findings demonstrate that long-term professional chess training could enhance spatial perception and reconfiguration and semantic processing efficiency for superior performance.