Visual Information Processing Research Articles

The Interaction of Linguistic and Visual Cues for the Processing of Case in Russian by Russian-German Bilinguals: An Eye Tracking Study.

Modulation of visual attention in the Visual World Paradigm relies on parallel processing of linguistic and visual information. Previous studies have argued that the human linguistic capacity includes an aspect of anticipation of upcoming material. Such anticipation can be triggered by both lexical and grammatical/morphosyntactic cues. In this study, we investigated the relationship between comprehension and prediction by testing how subtle changes in visual representations can affect the processing of grammatical case cues in Russian by Russian-German bilingual children (n = 49, age 8-13). The linguistic manipulation followed previous designs, contrasting SVO and OVS sentences, where the first NP (NP1) was marked with nominative or accusative case, respectively. Three types of visual displays were compared: (i) individual referents (potential agent/theme); (ii) pairs of referents (NP1 + potential agent/theme); and (iii) events (representing interactions between the referents). Participants were significantly more sensitive to the case manipulation when presented with events compared to the other two types of visual display. This suggests that they were able to quickly integrate the thematic role information signaled by grammatical case in the event representations. However, they were less likely to use the case information to anticipate upcoming arguments when the target pictures represented individual referents or pairs of noninteracting referents. We hypothesize that the process of argument anticipation is mediated by the activation of syntactic templates (SVO or OSV, depending on the case marking on NP1). The relatively weak anticipation effect observed may be attributed to the absence, or weak representation, of the noncanonical OVS template in the bilingual children's long-term memory.

Identifying individual's distractor suppression using functional connectivity between anatomical large-scale brain regions

Distractor suppression (DS) is crucial in goal-oriented behaviors, referring to the ability to suppress irrelevant information. Current evidence points to the prefrontal cortex as an origin region of DS, while subcortical, occipital, and temporal regions are also implicated. The present study aimed to examine the contribution of communications between these brain regions to visual DS. To do it, we recruited two independent cohorts of participants for the study. One cohort participated in a visual search experiment where a salient distractor triggering distractor suppression to measure their DS and the other cohort filled out a Cognitive Failure Questionnaire to assess distractibility in daily life. Both cohorts collected resting-state functional magnetic resonance imaging (rs-fMRI) data to investigate function connectivity (FC) underlying DS. First, we generated predictive models of the DS measured in visual search task using resting-state functional connectivity between large anatomical regions. It turned out that the models could successfully predict individual's DS, indicated by a significant correlation between the actual and predicted DS (r = 0.32, p < 0.01). Importantly, Prefrontal-Temporal, Insula-Limbic and Parietal-Occipital connections contributed to the prediction model. Furthermore, the model could also predict individual's daily distractibility in the other independent cohort (r = –0.34, p < 0.05). Our findings showed the efficiency of the predictive models of distractor suppression encompassing connections between large anatomical regions and highlighted the importance of the communications between attention-related and visual information processing regions in distractor suppression. Current findings may potentially provide neurobiological markers of visual distractor suppression.

The Gaze of Schizophrenia Patients Captured by Bottom-up Saliency

Schizophrenia (SCHZ) notably impacts various human perceptual modalities, including vision. Prior research has identified marked abnormalities in perceptual organization in SCHZ, predominantly attributed to deficits in bottom-up processing. Our study introduces a novel paradigm to differentiate the roles of top-down and bottom-up processes in visual perception in SCHZ. We analysed eye-tracking fixation ground truth maps from 28 SCHZ patients and 25 healthy controls (HC), comparing these with two mathematical models of visual saliency: one bottom-up, based on the physical attributes of images, and the other top-down, incorporating machine learning. While the bottom-up (GBVS) model revealed no significant overall differences between groups (beta = 0.01, p = 0.281, with a marginal increase in SCHZ patients), it did show enhanced performance by SCHZ patients with highly salient images. Conversely, the top-down (EML-Net) model indicated no general group difference (beta = −0.03, p = 0.206, lower in SCHZ patients) but highlighted significantly reduced performance in SCHZ patients for images depicting social interactions (beta = −0.06, p < 0.001). Over time, the disparity between the groups diminished for both models. The previously reported bottom-up bias in SCHZ patients was apparent only during the initial stages of visual exploration and corresponded with progressively shorter fixation durations in this group. Our research proposes an innovative approach to understanding early visual information processing in SCHZ patients, shedding light on the interplay between bottom-up perception and top-down cognition.

Microsaccades reflect attention shifts: a mini review of 20 years of microsaccade research.

Microsaccades are small, involuntary eye movements that occur during fixation. Since the 1950s, researchers have conducted extensive research on the role of microsaccades in visual information processing, and found that they also play an important role in human advanced visual cognitive activities. Research over the past 20 years further suggested that there is a close relationship between microsaccades and visual attention, yet lacking a timely review. The current article aims to provide a state-of-the-art review and bring microsaccades studies into the sight of attention research. We firstly introduce basic characteristics about microsaccades, then summarized the empirical evidence supporting the view that microsaccades can reflect both external (perception) and internal (working memory) attention shifts. We finally conclude and highlight three promising avenues for future research.

Sex-differential patterns of neuropsychological functioning in adults with attention-deficit/hyperactivity disorder

BackgroundThe sex-differential prevalence of attention-deficit/hyperactivity disorder (ADHD) varies across the lifespan, but little is known about sex differences in executive functions in adults with ADHD. MethodsWe assessed 261 adults, aged 18–40 years, diagnosed with ADHD (170 males [assigned at birth], aged 25.81 ± 5.49; 91 females, aged 27.76 ± 5.42) and 308 neurotypical adults (176 males, aged 24.62 ± 5.14; 132 female, aged 25.37 ± 5.42) via psychiatric interviews to confirm ADHD and other psychiatric diagnoses. They were assessed by the Cambridge Neuropsychological Testing Automated Battery (CANTAB) on Reaction Time (arousal/processing speed), Rapid Visual Information Processing (sustained attention), Spatial Span (spatial memory), Spatial Working Memory, Intradimentional/Extradimensional Shift (set-shifting), and Stocking of Cambridge (spatial planning). The primary analyses were adjusted for age, full-scale IQ, and co-occurring psychiatric conditions. ResultsAdults with ADHD had various co-occurring psychiatric conditions without sex differences in ADHD-neurotypical differences. Both adult males and females with ADHD performed poorer in all CANTAB tasks than same-sex neurotypical adults. Significant sex-moderating effects were observed in neuropsychological performance, including greater ADHD-neurotypical differences in arousal for females than males and in location memory for spatial tasks in males than females. ConclusionThere were no sex-moderating effects in the presence of co-occurring psychiatric conditions in adult ADHD. However, there were sex-moderating effects on how ADHD related to neuropsychological functioning in adulthood. ADHD was associated with more challenges in arousal/processing speed in females and more challenges in strategy use or inhibition in spatial memory in males.

Effects of the active botanical blend "WKUP GT" on attention and cognitive functions after lunch in healthy volunteers.

"WKUP GT", a low caffeine beverage consisting of carob, Guarana, Green Tea and Elderberry extracts was studied on attention and cognitive functions post-lunch in a pilot randomized double blind placebo controlled trial. Thirty healthy volunteers were included in a crossover design trial, presenting five beverages randomly assigned to the following groups: placebo, "WKUP GT" (single, double or triple doses), or "caffeine" as an active control. Hemodynamic measurements were assessed as safety outcomes. The Cambridge Neuropsychological Test Automated Battery (CANTAB), was used to evaluate the patients when beverages were consumed 30 and 120min after lunch (respectively Delta30 and Delta120 considering baseline). Drinking "caffeine" or "WKUP GT" after lunch, showed significant improvement (p<0.05) in rapid visual information processing compared to placebo (Delta120 of "caffeine", "WKUP" single and double). In addition, improvement in Multitasking Test (Delta30 for "WKUP" double, and Delta120 for "caffeine" and "WKUP" triple compared to placebo) was observed. "WKUP" triple also showed significant improvement for "memory" when compared to placebo (Delta120). Compared to "caffeine", WKUP GT did not increase systolic blood pressure. "WKUP GT" showed improvements for attention, memory, psychomotor and executive function tasks after lunch without increase in pulse rate.

IMDE-UGAN: Improved Memetic Direction Exploitation Optimized U-Net Generative Adversarial Network for Classification of Diabetic Retinopathy

The most important human organ is the eye which is essential for the processing and absorbing of external visual information. Diabetic retinopathy (DR) is the primary factor contributing to the global increase in blindness. To maintain eye health, people have been paying lots of attention to the problem. However, there are still lots of people who have eye problems all around the world. Thus, we proposed the Improved Memetic Direction Exploitation Optimized U-Net Generative Adversarial Network (IMDE-optimized U-Net GAN) model for DR grading. Also, for Multimodal Optimization Problems (MMOPs), a Niching Competition-based Memetic Direction Exploitation (NC-MDE) method is proposed with adaptive local search operations. Additionally, SPatially-ADaptivE (SPADE)-based conditional GANs are used to segment DR. The U-Net GAN model is used to categorize DR images. In the discriminator design, the standard classification network is modified to create the decoder-encoder network known as U-Net. The complete network error of the U-Net GAN architecture is modeled using the IMDE archives. The various performance metrics are used in the method for testing the proposed including accuracy, specificity, sensitivity, and ROC curve. As a result, the proposed method achieves 98.89% of accuracy, 98.54% for sensitivity, and specificity, it achieves 98.67%.

Impaired eye movements in Parkinson's disease and their relationship to top–down and bottom–up neural processing

AbstractIntroductionEye movement disorder in patients with Parkinson's disease (PD) is less likely to appear when observing complex images compared with simple images. However, in case of auditory stimuli, meaningful stimuli can promote PD movement. Thus, we measured visual search movements with an eye tracker to investigate whether visual search changes in PD depending on the meaningfulness of visual stimuli; additionally, we measured event‐related potentials (ERPs) to neurophysiologically examine visual information processing in PD.MethodsData from 11 patients with cognitively unimpaired PD and 10 neurologically healthy individuals (controls) were used in this study. We simultaneously measured eye tracking and ERPs during the observation of three types of images: operation, noun, and meaningless figures. We compared intergroup differences in visual search parameters, such as saccade count, fixation time, and saccade amplitude, as well as in ERPs vertex‐to‐vertex amplitudes and latency among P1, N1, P2, and N2 at the posterior regions. These ERPs reflect different stages of visual information processing and provide insights into the underlying neural mechanisms of visual search in PD.ResultsAll visual search parameters were consistently smaller in the PD group than in the control group, regardless of visual stimulus. The saccade count in the PD group was significantly lower than in the control group for operation and meaningless figures but not for noun figures. Further, P1 and N1 amplitudes—bottom–up processing—were smaller in PD group when viewing operation figures and N2 amplitudes—top–down processing—were larger in PD group when viewing operation and meaningless figures.ConclusionsPD's visual search movements may change depending on the meaningfulness of visual stimuli. Further, the abnormal visual search movements in PD may be due to insufficient bottom–up processing and excessive top–down processing.Plain Language SummaryParkinson's disease (PD) is a neurodegenerative disorder that can cause eye movement disorders. People with PD may have difficulty searching for and processing visual information. In this study, we investigated how meaningfulness affects visual search movements and visual information processing in people with PD. We measured eye movements and brain activity in response to different types of visual stimuli, including meaningful and meaningless images, and compared them to a group of healthy control participants. Our results showed that PD patients had fewer eye movements and different brain activity patterns compared to healthy controls, regardless of the meaningfulness of the visual stimuli. However, we also found that the meaningfulness of visual stimuli had an effect on visual search movements in PD patients. This suggests that meaningfulness can impact the way people with PD process visual information. Understanding these differences could help in the development of new therapies to improve visual processing in people with PD.

Impact of online poker gambling on behavioural and neurophysiological responses to a virtual gambling task.

Online poker gambling (OPG) involves various executive control processes and emotion regulation. In this context, we hypothesized that online poker players, accustomed to handling virtual cards, would show high performance on computerized decision-making tasks such as the Iowa Gambling Task (IGT). Using press advertisements, we recruited a non-gambler group (NG; n= 20) and an OPG group (n= 22). All participants performed the IGT while their cerebral activity was recorded by electroencephalography. Compared with the OPG group, the NG group showed significantly better progression in the IGT in the last trials. Recording of brain activity revealed the appearance of a temporal map between 150 and 175 ms specific to the gain condition in both groups. A second map was observed at 215-295 ms specifically in the NG group, and the generators were identified in the occipital regions. This activity is indicative of a high level of visual awareness; thus, it reflects additional processing of visual information, which can be assumed to be induced by the lower exposure of the NGs to online card games. We hypothesize that the absence of this activity in the OPG group might be due to their online habituation to virtual environments.

Mesoscale organization of ventral and dorsal visual pathways in macaque monkey revealed by 7T fMRI

In human and nonhuman primate brains, columnar (mesoscale) organization has been demonstrated to underlie both lower and higher order aspects of visual information processing. Previous studies have focused on identifying functional preferences of mesoscale domains in specific areas; but there has been little understanding of how mesoscale domains may cooperatively respond to single visual stimuli across dorsal and ventral pathways. Here, we have developed ultrahigh-field 7 T fMRI methods to enable simultaneous mapping, in individual macaque monkeys, of response in both dorsal and ventral pathways to single simple color and motion stimuli. We provide the first evidence that anatomical V2 cytochrome oxidase-stained stripes are well aligned with fMRI maps of V2 stripes, settling a long-standing controversy. In the ventral pathway, a systematic array of paired color and luminance processing domains across V4 was revealed, suggesting a novel organization for surface information processing. In the dorsal pathway, in addition to high quality motion direction maps of MT, MST and V3A, alternating color and motion direction domains in V3 are revealed. As well, submillimeter motion domains were observed in peripheral LIPd and LIPv. In sum, our study provides a novel global snapshot of how mesoscale networks in the ventral and dorsal visual pathways form the organizational basis of visual objection recognition and vision for action.

Mapping the routes of perception: Hemispheric asymmetries in signal propagation dynamics.

The visual system has long been considered equivalent across hemispheres. However, an increasing amount of data shows that functional differences may exist in this regard. We therefore tried to characterize the emergence of visual perception and the spatiotemporal dynamics resulting from the stimulation of visual cortices in order to detect possible interhemispheric asymmetries. Eighteen participants were tested. Each of them received 360 transcranial magnetic stimulation (TMS) pulses at phosphene threshold intensity over left and right early visual areas while electroencephalography was being recorded. After each single pulse, participants had to report the presence or absence of a phosphene. Local mean field power analysis of TMS-evoked potentials showed an effect of both site (left vs. right TMS) of stimulation and hemisphere (ipsilateral vs. contralateral to the TMS): while right TMS determined early stronger activations, left TMS determined later stronger activity in contralateral electrodes. The interhemispheric signal propagation index revealed differences in how TMS-evoked activity spreads: left TMS-induced activity diffused contralaterally more than right stimulation. With regard to phosphenes perception, distinct electrophysiological patterns were found to reflect similar perceptual experiences: left TMS-evoked phosphenes are associated with early occipito-parietal and frontal activity followed by late central activity; right TMS-evoked phosphenes determine only late, fronto-central, and parietal activations. Our results show that left and right occipital TMS elicits differential electrophysiological patterns in the brain, both per se and as a function of phosphene perception. These distinct activation patterns may suggest a different role of the two hemispheres in processing visual information and giving rise to perception.

Dbx1 is a dorsal midbrain-specific determinant of GABAergic neuron fate and regulates differentiation of the dorsal midbrain into the inferior and superior colliculi.

The mechanism underlying the differentiation of the dorsal midbrain into two morphologically and functionally distinct compartments, the inferior colliculus (IC) and superior colliculus (SC), which process auditory and visual information, respectively, remains largely unexplored. By using null and conditional alleles, we uncover the roles of a homeodomain transcription factor Dbx1 in the regulation of IC and SC differentiation. We show that Dbx1 regulates GABAergic neuron development in the dorsal midbrain. In the absence of Dbx1 function, the dorsal-most m1-m2 progenitor domains in the midbrain fail to activate GABAergic neuron-specific gene expression and instead switch to a glutamatergic phenotype. These results identify Dbx1 as a dorsal midbrain-specific GABAergic determinant that regulates the selector genes, Helt, Gata2, and Tal2. Furthermore, we demonstrate that maturation of the dorsal midbrain into the IC and SC is dependent on Dbx1. Null mutation of Dbx1 impairs the identity and fate of IC and SC neurons. Surprisingly, Dbx1 is required for preventing IC into SC fate switch and thus Dbx1-deficient IC neurons undergo acquisition of SC identity. Conditional inactivation of Dbx1 at late developmental phase leads to alteration in the identity and fate of the IC, but not the SC. These results suggest that SC differentiation is dependent on the early function of Dbx1, and that the IC requires the prolonged action for its normal formation. Furthermore, we uncover that Tcf7l2 acts downstream of Dbx1 selectively to promote IC differentiation. Altogether, our study identifies a molecular mechanism underlying spatial and temporal control of dorsal midbrain development.

Association between deficient levels of vitamin D and the occurrence of selected retinal diseases

Introduction and Purpose:&#x0D; Vision originates in the eye's retina, a complex structure essential for processing visual information. The connection between nutritional inadequacy, particularly vitamin deficiencies, and overall health, including ocular health, has long been acknowledged. Recent studies highlight the potential impact of vitamin D, a crucial nutrient, on retinal health. The aim is to investigate the association between low levels of vitamin D and retinal diseases like age-related macular degeneration (AMD) and diabetic retinopathy (DR), and to evaluate the potential benefits of vitamin D supplementation or lifestyle changes for at-risk patients.&#x0D; Description of the State of Knowledge:&#x0D; AMD, a significant cause of blindness in the elderly, involves factors like oxidative stress and inflammation. Various stages of AMD require different treatments, with limited options for advanced stages. DR, a complication of diabetes, leads to conditions such as retinal ischemia and neovascularization. Both conditions are potentially influenced by vitamin D levels. Studies show mixed results regarding the impact of vitamin D on these diseases. Some suggest lower levels may increase risk, while others report no significant effect or even contradictory findings.&#x0D; Conclusions:&#x0D; While some studies indicate a potential association between low vitamin D levels and the occurrence of retinal diseases, discrepancies exist in the findings. Lower vitamin D concentrations may be linked to a higher frequency of AMD and DR, but the evidence is not consistent across all studies. Therefore, a more in-depth exploration of this subject is warranted to draw conclusive insights. It is crucial to consider supplementation or dietary changes in cases of vitamin D deficiency, given its potential impact on systemic health.

Raising awareness of Cerebral Visual Impairment (CVI) through the use of educational videos: One size does not fit all

Cerebral visual impairment (CVI) is a leading cause of childhood visual impairment in Western countries. This complex condition impacts affected children’s ability to see and process visual information, affecting their learning and development. Although early intervention is beneficial, many children with CVI live with this condition without this being identified. This is, in part, due to unfamiliarity with the condition among health care and education professionals. In recent years, more information has become available, and attempts have been made to explain this condition in accessible formats, such as educational videos. For this study, students and professionals in health care and education were asked to rate their knowledge about CVI, to watch three short educational videos about CVI, and to complete a survey about the use of these videos as a tool to raise awareness and to increase understanding of the condition. The study shows that educational videos can be used effectively to raise awareness of CVI among educational and health care students and professionals. Furthermore, the study shows that there is a mix of understanding, confidence and learning styles across the key professionals supporting children with CVI. As a result, different videos are effective for different audiences and therefore no one size fits all.

Neural processing of prototypicality and simplicity of product design in forming design preferences.

The current study investigates the neural correlates when processing prototypicality and simplicity-affecting the preference of product design. Despite its significance, not much is known about how our brain processes these visual qualities of design when forming design preferences. We posit that, although fluency is the perceptual judgment accounting for the positive effects of both prototypicality and simplicity on design preference, the neural substrates for the fluency judgment associated with prototypicality would differ from those associated with simplicity. To investigate these issues, we conducted an fMRI study of preference decisions for actual product designs with different levels of prototypicality and simplicity. The results show a significant functional gradient between the preference processing of simplicity and prototypicality-i.e., involvement of the early ventral stream of visual information processing for simplicity evaluation but recruitment of the late ventral stream and parietal-frontal brain regions for prototypicality evaluation. The interaction between the simplicity and prototypicality evaluations was found in the extrastriate cortex in the right hemisphere. The segregated brain involvements suggest that the fluency judgment for prototypicality and simplicity contribute to preference choice in different levels of cognitive hierarchy in the perceptual mechanism of the design preference.

EEG-based hierarchical classification of level of demand and modality of auditory and visual sensory processing

Objective. To date, most research on electroencephalography (EEG)-based mental workload detection for passive brain-computer interface (pBCI) applications has focused on identifying the overall level of cognitive resources required, such as whether the workload is high or low. We propose, however, that being able to determine the specific type of cognitive resources being used, such as visual or auditory, would also be useful. This would enable the pBCI to take more appropriate action to reduce the overall level of cognitive demand on the user. For example, if a high level of workload was detected and it is determined that the user is primarily engaged in visual information processing, then the pBCI could cause some information to be presented aurally instead. In our previous work we showed that EEG could be used to differentiate visual from auditory processing tasks when the level of processing is high, but the two modalities could not be distinguished when the level of cognitive processing demand was very low. The current study aims to build on this work and move toward the overall objective of developing a pBCI that is capable of predicting both the level and the type of cognitive resources being used. Approach. Fifteen individuals undertook carefully designed visual and auditory tasks while their EEG data was being recorded. In this study, we incorporated a more diverse range of sensory processing conditions including not only single-modality conditions (i.e. those requiring one of either visual or auditory processing) as in our previous study, but also dual-modality conditions (i.e. those requiring both visual and auditory processing) and no-task/baseline conditions (i.e. when the individual is not engaged in either visual or auditory processing). Main results. Using regularized linear discriminant analysis within a hierarchical classification algorithm, the overall cognitive demand was predicted with an accuracy of more than 86%, while the presence or absence of visual and auditory sensory processing were each predicted with an accuracy of approximately 70%. Significance. The findings support the feasibility of establishing a pBCI that can determine both the level and type of attentional resources required by the user at any given moment. This pBCI could assist in enhancing safety in hazardous jobs by triggering the most effective and efficient adaptation strategies when high workload conditions are detected.

Multisensory Ferroelectric Semiconductor Synapse for Neuromorphic Computing

AbstractIntegrated multifunctionality in visual information processing is crucial in the artificial intelligence era. Compared to the parallel human vision system, current bionic vision devices exhibit a complex structure with single functionality, challenging intelligent processing and integration. Here, a multisensory artificial synapse with a crossbar structure comprising graphene/α‐In2Se3/graphene layers is demonstrated, merging sensing, memory, and computing while mimicking various synaptic properties. The Schottky barrier height is modulated by the polarization of ferroelectric semiconductor α‐In2Se3, enabling reconfigurable device conductance and photoresponsivity. This conductance emulates synaptic short‐term and long‐term plasticity through electrical pulse modulation, boasting a rapid 40 ns programming speed. The device also exhibits linearly regulated photoresponsivity under illumination, with synaptic plasticity from optical pulses. The fusion of electronic and optoelectronic devices enables both image front‐end processing and advanced post‐processing. In‐sensor front‐end processing enhances subsequent processing efficiency, with pattern recognition accuracy reaching 97%. This design fosters the advancement of multisensory and highly integrated neuromorphic vision systems.

Dynamic graph CNN based semantic segmentation of concrete defects and as-inspected modeling

Obtaining accurate information of defective areas of infrastructures helps to perform repair actions more efficiently. Recently, LiDAR scanners have been used for the inspection of surface defects. Moreover, machine learning methods have attracted the attention of researchers for semantic segmentation and classification based on point cloud data. Although much work has been done for processing visual information with images, research on machine learning methods for semantic segmentation of raw point cloud data is still in its early stages. Moreover, LiDAR technology is commonly used to create as-is BIM models. Therefore, the BIM model needs to be integrated with the results of defect semantic segmentation after the LiDAR-based inspection. Addressing the above issues, this paper has the following objectives: (1) Developing a method for point cloud-based concrete surface defects semantic segmentation; and (2) Developing a semi-automated process for as-inspected modeling. The challenges related to the size of the dataset and imbalanced classes are studied. Sensitivity analysis is applied to capture the best combination of hyperparameters and investigate their effects on the network performance. The proposed method resulted in 98.56% and 96.50% recalls for semantic segmentation of cracks and spalls, respectively. Furthermore, post-processing of the results of the concrete surface defects semantic segmentation is done to semi-automate the process of as-inspected modeling. As-inspected BIM includes the updated information of the facilities at the time of data collection. This semi-automated process made it possible to manage and visualize the detected defects by extracting their dimensions and identifying the conditions on the 3D model.

Bi-sinusoidal light stimulation reveals an enhanced response power and reduced phase coherence at the visual cortex in migraine.

Migraine is associated with enhanced visual sensitivity during and outside attacks. Processing of visual information is a highly non-linear process involving complex interactions across (sub)cortical networks. In this exploratory study, we combined electroencephalography with bi-sinusoidal light stimulation to assess non-linear features of visual processing in participants with migraine. Twenty participants with migraine (10 with aura, 10 without aura) and ten non-headache controls were measured (outside attacks). Participants received bi-sinusoidal 13 + 23 Hz red light visual stimulation. Electroencephalography spectral power and multi-spectral phase coherence were compared between groups at the driving stimulation frequencies together with multiples and combinations of these frequencies (harmonic and intermodulation frequencies) caused by non-linearities. Only at the driving frequency of 13 Hz higher spectral power was found in migraine with aura participants compared with those with migraine without aura and controls. Differences in phase coherence were present for 2nd, 4th, and 5th-order non-linearities in those with migraine (migraine with and without aura) compared with controls. Bi-sinusoidal light stimulation revealed evident non-linearities in the brain's electroencephalography response up to the 5th order with reduced phase coherence for higher order interactions in interictal participants with migraine. Insight into interictal non-linear visual processing may help understand brain dynamics underlying migraine attack susceptibility. Future research is needed to determine the clinical value of the results.

Attention Drives Visual Processing and Audiovisual Integration During Multimodal Communication.

During communication in real-life settings, our brain often needs to integrate auditory and visual information and at the same time actively focus on the relevant sources of information, while ignoring interference from irrelevant events. The interaction between integration and attention processes remains poorly understood. Here, we use rapid invisible frequency tagging and magnetoencephalography to investigate how attention affects auditory and visual information processing and integration, during multimodal communication. We presented human participants (male and female) with videos of an actress uttering action verbs (auditory; tagged at 58 Hz) accompanied by two movie clips of hand gestures on both sides of fixation (attended stimulus tagged at 65 Hz; unattended stimulus tagged at 63 Hz). Integration difficulty was manipulated by a lower-order auditory factor (clear/degraded speech) and a higher-order visual semantic factor (matching/mismatching gesture). We observed an enhanced neural response to the attended visual information during degraded speech compared to clear speech. For the unattended information, the neural response to mismatching gestures was enhanced compared to matching gestures. Furthermore, signal power at the intermodulation frequencies of the frequency tags, indexing nonlinear signal interactions, was enhanced in the left frontotemporal and frontal regions. Focusing on the left inferior frontal gyrus, this enhancement was specific for the attended information, for those trials that benefitted from integration with a matching gesture. Together, our results suggest that attention modulates audiovisual processing and interaction, depending on the congruence and quality of the sensory input.