Abstract: Prominent theories of visual working memory postulate that the capacity to maintain a particular visual feature is fixed. In contrast to these theories, recent studies have demonstrated that meaningful objects are better remembered than simple, nonmeaningful stimuli. Here, we tested whether this is solely because meaningful stimuli can recruit additional features—and thus more storage capacity—or whether simple visual features that are not themselves meaningful can also benefit from being part of a meaningful object. Across five experiments (30 young adults each), we demonstrated that visual working memory capacity for color is greater when colors are part of recognizable real-world objects compared with unrecognizable objects. Our results indicate that meaningful stimuli provide a potent scaffold to help maintain simple visual feature information, possibly because they effectively increase the objects’ distinctiveness from each other and reduce interference.

Abstract: LED lighting has been widely used in various scenes, but there are few studies on the impact of LED lighting on visual comfort in sustained attention tasks. This paper aims to explore the influence of correlated color temperature (CCT) and illuminance level in LED lighting parameters on human visual comfort. We selected 46 healthy college students (23 male and 23 female). The ages ranged from 22 to 26 years old (average age was 24.2 years). Electroencephalogram (EEG) signals, sustained attention to response test (SART) parameters and subjective evaluation parameters of subjects performing sustained attention tasks under LED lighting were obtained. The results under different conditions were compared, and the effects of experimental lighting parameters on visual comfort were discussed. The results showed that the LED lighting with CCT of 3300 K and illuminance of 300 lx was more comfortable than other combined conditions. In the subjective perception of subjects, 4000 K CCT also had good visual comfort evaluation and caused good task performance. Therefore, our study showed that in sustained attention tasks, when LED lighting conditions were CCT of 3300 and 4300 K and illuminance level was 300 lx, the visual comfort of the subjects was better.

Abstract: Recently, a considerable number of studies in computer vision involve deep neural architectures called vision transformers. Visual processing in these models incorporates computational models that are claimed to implement attention mechanisms. Despite an increasing body of work that attempts to understand the role of attention mechanisms in vision transformers, their effect is largely unknown. Here, we asked if the attention mechanisms in vision transformers exhibit similar effects as those known in human visual attention. To answer this question, we revisited the attention formulation in these models and found that despite the name, computationally, these models perform a special class of relaxation labeling with similarity grouping effects. Additionally, whereas modern experimental findings reveal that human visual attention involves both feed-forward and feedback mechanisms, the purely feed-forward architecture of vision transformers suggests that attention in these models cannot have the same effects as those known in humans. To quantify these observations, we evaluated grouping performance in a family of vision transformers. Our results suggest that self-attention modules group figures in the stimuli based on similarity of visual features such as color. Also, in a singleton detection experiment as an instance of salient object detection, we studied if these models exhibit similar effects as those of feed-forward visual salience mechanisms thought to be utilized in human visual attention. We found that generally, the transformer-based attention modules assign more salience either to distractors or the ground, the opposite of both human and computational salience. Together, our study suggests that the mechanisms in vision transformers perform perceptual organization based on feature similarity and not attention.

Abstract: Monetary value enhances visual perception and attention and boosts activity in the primary visual cortex, however, it is still unclear whether monetary value can modulate the conscious access to rewarding stimuli. Here we investigate this issue by employing a breaking continuous flash suppression (b-CFS) paradigm. We measured suppression durations of sinusoidal gratings having orthogonal orientations under CFS in adult volunteers before and after a short session of Pavlovian associative learning in which each orientation was arbitrarily associated either with high or low monetary reward. We found that monetary value accelerated the access to visual awareness during CFS. Specifically, after the associative learning, suppression durations of the visual stimulus associated with high monetary value were shorter compared to the visual stimulus associated with low monetary value. Critically, the effect was replicated in a second experiment using a detection task for b-CFS that was orthogonal to the reward associative learning. These results indicate that monetary reward facilitates the access to awareness of visual stimuli associated with monetary value probably by boosting their representation at the early stages of visual processing in the brain.

Abstract: Flicker light stimulation (FLS) uses stroboscopic light on closed eyes to induce transient visual hallucinatory phenomena, such as the perception of geometric patterns, motion, and colours. It remains an open question where the neural correlates of these hallucinatory experiences emerge along the visual pathway. To allow future testing of suggested underlying mechanisms (e.g., changes in functional connectivity, neural entrainment), we sought to systematically characterise the effects of frequency (3 Hz, 8 Hz, 10 Hz and 18 Hz) and rhythmicity (rhythmic and arrhythmic conditions) on flicker-induced subjective experiences. Using a novel questionnaire, we found that flicker frequency and rhythmicity significantly influenced the degree to which participants experienced simple visual hallucinations, particularly the perception of Klüver forms and dynamics (e.g., motion). Participants reported their experience of geometric patterns and dynamics was at highest intensity during 10 Hz rhythmic stimulation. Further, we found that frequency-matched arrhythmic FLS strongly reduced these subjective effects compared to equivalent rhythmic stimulation. Together, these results provide evidence that flicker rhythmicity critically contributes to the effects of FLS beyond the effects of frequency alone, indicating that neural entrainment may drive the induced phenomenal experience.

Abstract: Maintaining perceptual experiences in visual working memory (VWM) allows us to flexibly accomplish various tasks, but some tasks come at a price. For example, comparing VWM representations to novel perceptual inputs can induce inadvertent memory distortions. If these distortions can persist, they may explain why everyday memories often become unreliable after people perform perceptual comparisons (e.g., eyewitness testimony). Here, we conducted two experiments to assess the consequences of perceptual comparisons using real-world objects that were temporarily maintained in VWM (n = 32) or recalled from visual long-term memory back into VWM (n = 30). In each experiment, young adults reported systematic memory distortions following perceptual comparisons. These distortions increased in magnitude with the delay between encoding and comparisons and were preserved when memories were retrieved again a day later. These findings suggest that perceptual comparisons play a mechanistic role in everyday memory distortions, including situations where memory accuracy is vital. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Abstract: While 3D visual saliency aims to predict regional importance of 3D surfaces in agreement with human visual perception and has been well researched in computer vision and graphics, latest work with eye-tracking experiments shows that state-of-the-art 3D visual saliency methods remain poor at predicting human fixations. Cues emerging prominently from these experiments suggest that 3D visual saliency might associate with 2D image saliency. This paper proposes a framework that combines a Generative Adversarial Network and a Conditional Random Field for learning visual saliency of both a single 3D object and a scene composed of multiple 3D objects with image saliency ground truth to 1) investigate whether 3D visual saliency is an independent perceptual measure or just a derivative of image saliency and 2) provide a weakly supervised method for more accurately predicting 3D visual saliency. Through extensive experiments, we not only demonstrate that our method significantly outperforms the state-of-the-art approaches, but also manage to answer the interesting and worthy question proposed within the title of this paper.

Abstract: Autism spectrum disorder (ASD) is associated with severe impairment in social functioning. Visual information processing provides nonverbal cues that support social interactions. ASD children exhibit abnormalities in visual orientation, continuous visual exploration, and visual–spatial perception, causing social dysfunction, and mechanisms underlying these abnormalities remain unclear. Transmission of visual information depends on the retina-lateral geniculate nucleus–visual cortex pathway. In ASD, developmental abnormalities occur in rapid expansion of the visual cortex surface area with constant thickness during early life, causing abnormal transmission of the peak of the visual evoked potential (P100). We hypothesized that abnormal visual perception in ASD are related to the abnormal visual information transmission and abnormal development of visual cortex in early life, what’s more, explored the mechanisms of abnormal visual symptoms to provide suggestions for future research.

Abstract: Abstract Parallel multisite recordings in the visual cortex of trained monkeys revealed that the responses of spatially distributed neurons to natural scenes are ordered in sequences. The rank order of these sequences is stimulus-specific and maintained even if the absolute timing of the responses is modified by manipulating stimulus parameters. The stimulus specificity of these sequences was highest when they were evoked by natural stimuli and deteriorated for stimulus versions in which certain statistical regularities were removed. This suggests that the response sequences result from a matching operation between sensory evidence and priors stored in the cortical network. Decoders trained on sequence order performed as well as decoders trained on rate vectors but the former could decode stimulus identity from considerably shorter response intervals than the latter. A simulated recurrent network reproduced similarly structured stimulus-specific response sequences, particularly once it was familiarized with the stimuli through non-supervised Hebbian learning. We propose that recurrent processing transforms signals from stationary visual scenes into sequential responses whose rank order is the result of a Bayesian matching operation. If this temporal code were used by the visual system it would allow for ultrafast processing of visual scenes.

Abstract: The neural underpinnings of enhanced locally oriented visual processing that are specific to autistics with a Wechsler's Block Design (BD) peak are largely unknown. Here, we investigated the brain correlates underlying visual segmentation associated with the well-established autistic superior visuospatial abilities in distinct subgroups using functional magnetic resonance imaging. This study included 31 male autistic adults (15 with (AUTp) and 16 without (AUTnp) a BD peak) and 28 male adults with typical development (TYP). Participants completed a computerized adapted BD task with models having low and high perceptual cohesiveness (PC). Despite similar behavioral performances, AUTp and AUTnp showed generally higher occipital activation compared with TYP participants. Compared with both AUTnp and TYP participants, the AUTp group showed enhanced task-related functional connectivity within posterior visuoperceptual regions and decreased functional connectivity between frontal and occipital-temporal regions. A diminished modulation in frontal and parietal regions in response to increased PC was also found in AUTp participants, suggesting heavier reliance on low-level processing of global figures. This study demonstrates that enhanced visual functioning is specific to a cognitive phenotypic subgroup of autistics with superior visuospatial abilities and reinforces the need to address autistic heterogeneity by good cognitive characterization of samples in future studies.

Abstract: The brain uses recent history when forming perceptual decisions. This results in carryover effects in perception. Although separate sensory and decisional carryover effects have been shown in many perceptual tasks, their existence and nature in temporal processing are unclear. Here, we investigated whether and how previous stimuli and previous choices affect subsequent duration perception, in vision and audition.In a series of three experiments, participants were asked to classify visual or auditory stimuli into "shorter" or "longer" duration categories. In experiment 1, visual and auditory stimuli were presented in separate blocks. Results showed that current duration estimates were repelled away from the previous trial's stimulus duration, but attracted towards the previous choice, in both vision and audition. In experiment 2, visual and auditory stimuli were pseudorandomly presented in one block. We found that sensory and decisional carryover effects occurred only when previous and current stimuli were from the same modality. Experiment 3 further investigated the stimulus dependence of carryover effects within each modality. In this experiment, visual stimuli with different shape topologies (or auditory stimuli with different audio frequencies) were pseudorandomly presented in one visual (or auditory) block. Results demonstrated sensory carryover (within each modality) despite task-irrelevant differences in visual shape topology or audio frequency. By contrast, decisional carryover was reduced (but still present) across different visual topologies and completely absent across different audio frequencies.These results suggest that serial dependence in duration perception is modality-specific. Moreover, repulsive sensory carryover effects generalize within each modality, whereas attractive decisional carryover effects are contingent on contextual details.

Abstract: Visual inputs are far from ideal in everyday situations such as in the fog where the contrasts of input stimuli are low. However, human perception remains relatively robust to contrast variations. To provide insights about the underlying mechanisms of contrast invariance, we addressed two questions. Do contrast effects disappear along the visual hierarchy? Do later stages of the visual hierarchy contribute to contrast invariance? We ran a behavioral experiment where we manipulated the level of stimulus contrast and the involvement of higher-level visual areas through immediate and delayed backward masking of the stimulus. Backward masking led to significant drop in performance in our visual categorization task, supporting the role of higher-level visual areas in contrast invariance. To obtain mechanistic insights, we ran the same categorization task on three state-of the-art computational models of human vision each with a different depth in visual hierarchy. We found contrast effects all along the visual hierarchy, no matter how far into the hierarchy. Moreover, that final layers of deeper hierarchical models, which had been shown to be best models of final stages of the visual system, coped with contrast effects more effectively. These results suggest that, while contrast effects reach the final stages of the hierarchy, those stages play a significant role in compensating for contrast variations in the visual system.

Abstract: Different individuals experience varying degrees of vividness in their visual mental images. The distribution of these variations across different imagery domains, such as object shape, color, written words, faces, and spatial relationships, remains unknown. To address this issue, we conducted a study with 117 healthy participants who reported different levels of imagery vividness. Of these participants, 44 reported experiencing absent or nearly absent visual imagery, a condition known as "aphantasia". These individuals were compared to those with typical (N = 42) or unusually vivid (N = 31) imagery ability. We used an online version of the French-language Battérie Imagination-Perception (eBIP), which consists of tasks tapping each of the above-mentioned domains, both in visual imagery and in visual perception. We recorded the accuracy and response times (RTs) of participants' responses. Aphantasic participants reached similar levels of accuracy on all tasks compared to the other groups (Bayesian repeated measures ANOVA, BF = 0.02). However, their RTs were slower in both imagery and perceptual tasks (BF = 266), and they had lower confidence in their responses on perceptual tasks (BF = 7.78e5). A Bayesian regression analysis revealed that there was an inverse correlation between subjective vividness and RTs for the entire participant group: higher levels of vividness were associated with faster RTs. The pattern was similar in all the explored domains. The findings suggest that individuals with congenital aphantasia experience a slowing in processing visual information in both imagery and perception, but the precision of their processing remains unaffected. The observed performance pattern lends support to the hypotheses that congenital aphantasia is primarily a deficit of phenomenal consciousness, or that it employs alternative strategies other than visualization to access preserved visual information.

Abstract: A large body of work has linked neural oscillations in the alpha-band (8–13 Hz) to visual perceptual outcomes. In particular, studies have found that alpha phase prior to stimulus onset predicts stimulus detection, and sensory responses and that the frequency of alpha can predict temporal properties of perception. These findings have bolstered the idea that alpha-band oscillations reflect rhythmic sampling of visual information, however the mechanisms of this are unclear. Recently two contrasting hypotheses have been proposed. According to the rhythmic perception account, alpha oscillations impose phasic inhibition on perceptual processing and primarily modulate the amplitude or strength of visual responses and thus the likelihood of stimulus detection. On the other hand, the discrete perception account proposes that alpha activity discretizes perceptual inputs thereby reorganizing the timing (not only the strength) of perceptual and neural processes. In this paper, we sought neural evidence for the discrete perception account by assessing the correlation between individual alpha frequencies (IAF) and the latency of early visual evoked event-related potential (ERP) components. If alpha cycles were responsible for shifting neural events in time, then we may expect higher alpha frequencies to be associated with earlier afferent visual ERPs. Participants viewed large checkerboard stimuli presented to either the upper or lower visual field that were designed to elicit a large C1 ERP response (thought to index feedforward primary visual cortex activation). We found no reliable correlation between IAF and the C1 latency, or subsequent ERP component latencies, suggesting that the timing of these visual-evoked potentials was not modulated by alpha frequency. Our results thus fail to find evidence for discrete perception at the level of early visual responses but leave open the possibility of rhythmic perception.

Abstract: Dynamic visual experience is the most common way for people to perceive a cityscape. Previous research reviews on cityscapes have mainly focused on spatial planning, social culture, economic development, ecological protection, etc., with little consideration of the impact of dynamic visual perception on the formation of cityscapes, which hinders the provision of references for the practice of people-centered urban design concepts. Therefore, this article selected 94 works in the relevant literature from 1940 to 2022 to conduct a critical review. First, we conceptualized the cityscape in light of earlier substantial discussions on the intimate relationship between dynamic visual perception and the cityscape. Then, we divided the relevant research from the past century and a half into three periods and summarized theoretical and practical research on the cityscape in these different periods from the perspective of dynamic visual perception. Among these, the refined research on interdisciplinary methods, including Visual Quality Assessment based on dynamic visual perception and visibility analysis algorithms based on digital technology, is emphatically described and discussed. Based on a comprehensive review, this article concludes that the main application scenarios for the existing research on dynamic visual perception are cityscape assessment and decision making. Finally, three avenues for future research are proposed.

Abstract: Previous studies have indicated that crossmodal visual predictions are instrumental in controlling early visual cortex activity. The exact time course and spatial precision of such crossmodal top-down influences on the visual cortex have been unknown. In the present study, participants were exposed to audiovisual combinations comprising one of two sounds and a Gabor patch either in the top left or in the bottom right visual field. Event-related potentials (ERPs) were recorded to these frequent crossmodal combinations (standards) as well as to trials in which the visual stimulus was omitted (omissions) or the visual and auditory stimuli were recombined (deviants). Standards and deviants elicited an ERP between 50 and 100 ms of opposite polarity known as the C1 effect commonly associated with retinotopic processing in early visual cortex. By contrast, a C1 effect was not observed in omission trials. Spatially specific omission and mismatch effects (deviants minus standards) started only later with a latency of 230 ms and 170 ms, respectively. These results suggest that crossmodal visual predictions control visual cortex activity in a spatially specific manner. However, visual predictions do not modulate visual cortex activity with the same timing as visual stimulation activates these areas but rather seem to involve distinct neural mechanisms. This article is part of the theme issue 'Decision and control processes in multisensory perception'.

Abstract: Aesthetics has been characterized as a triadic interaction of perceptual, emotional, and conceptual neural systems (e.g., Chatterjee & Vartanian, 2014). There has been much empirical effort to identify the visual features that contribute to the perceptual component of this triad (e.g., Mather, 2020). Here, we measured infants' visual preferences and adults' aesthetic preferences for 40 of van Gogh's landscape paintings and investigated the contribution of the chromatic and spatial image statistics of the art to infants' and adults' responses. We found that infants' and adults' responses were significantly related: infants looked longer at the art that the adults found more pleasant. We also found that our combination of chromatic and spatial image statistics could account for around two thirds of the variance in infant looking and adult pleasantness ratings. The amount of variation in the luminance and saturation of the art's pixels contributed to both infants' visual preferences and adults' aesthetic preferences, potentially identifying two "perceptual primitives" of aesthetics that can be traced back to early sensory biases in infancy. We also identified important differences in the types of image statistics that predict infants' and adults' responses. We discuss the findings in relation to theories of aesthetics, natural scene statistics, and infant vision and perception.

Abstract: Sensory perception is dramatically influenced by the context. Models of contextual neural surround effects in vision have mostly accounted for Primary Visual Cortex (V1) data, via nonlinear computations such as divisive normalization. However, surround effects are not well understood within a hierarchy, for neurons with more complex stimulus selectivity beyond V1. We utilized feedforward deep convolutional neural networks and developed a gradient-based technique to visualize the most suppressive and excitatory surround. We found that deep neural networks exhibited a key signature of surround effects in V1, highlighting center stimuli that visually stand out from the surround and suppressing responses when the surround stimulus is similar to the center. We found that in some neurons, especially in late layers, when the center stimulus was altered, the most suppressive surround surprisingly can follow the change. Through the visualization approach, we generalized previous understanding of surround effects to more complex stimuli, in ways that have not been revealed in visual cortices. In contrast, the suppression based on center surround similarity was not observed in an untrained network. We identified further successes and mismatches of the feedforward CNNs to the biology. Our results provide a testable hypothesis of surround effects in higher visual cortices, and the visualization approach could be adopted in future biological experimental designs.

Abstract: The basic computations performed in the human early visual cortex are the foundation for visual perception. While we know a lot about these computations from work in non-human animals, a key missing piece is how the coding of visual features relates to our perceptual experience. To investigate visual feature coding, interactions, and their relationship to human perception, we investigated neural responses and perceptual similarity judgements to a large set of visual stimuli that varied parametrically along four feature dimensions. We measured neural responses using electroencephalography (N=16) to 256 grating stimuli that varied in orientation, spatial frequency, contrast, and colour. We then mapped the response profiles of the neural coding of each visual feature and their interactions, and related these to independently obtained behavioural judgements of stimulus similarity. The results confirmed fundamental principles of feature coding in the visual system, such that all four features were processed simultaneously but differed in their dynamics, and there was distinctive conjunction coding for different combinations of features in the neural responses. Importantly, modelling of the behaviour revealed that every feature contributed to perceptual experience, despite the untargeted nature of the behavioural task. Further, the relationship between neural coding and behaviour was evident from initial processing stages, signifying that the fundamental features, not just their interactions, are crucial for perceptual experience. This study highlights the importance of understanding how feature coding progresses through the visual hierarchy and the relationship between different stages of processing and perception.

Abstract: Neurons in the inferotemporal (IT) cortex respond selectively to complex visual features, implying their role in object perception. However, perception is subjective and cannot be read out from neural responses; thus, bridging the causal gap between neural activity and perception demands independent characterization of perception. Historically though, the complexity of the perceptual alterations induced by artificial stimulation of IT cortex has rendered them impossible to quantify. Here we addressed this old problem by combining machine learning with high-throughput behavioral optogenetics in macaque monkeys. In closed-loop experiments, we generated complex and highly specific images that the animal could not discriminate from the state of being cortically stimulated. These images, named “perceptograms” for the first time, reveal and depict the contents of the complex hallucinatory percepts induced by local neural perturbation in IT cortex. Furthermore, we found that the nature and magnitude of these hallucinations highly depend on concurrent visual input, stimulation location, and intensity. Objective characterization of stimulation-induced perceptual events opens the door to developing a mechanistic theory of visual perception. Further, it enables us to make better visual prosthetic devices and gain a greater understanding of visual hallucinations in mental disorders. One-Sentence Summary Combining state-of-the-art AI with high-throughput closed-loop brain stimulation experiments, for the first time, we took “pictures” of the complex and subjective visual hallucinations induced by local stimulation in the inferior temporal cortex, a cortical area associated with object recognition.

Abstract: Abstract Visual perception and mental imagery have been shown to share a hierarchical topological visual structure of neural representation, despite the existence of dissociation of neural substrate between them in function and structure. However, we have limited knowledge about how the visual hierarchical cortex is involved in visual perception and visual imagery in a unique and shared fashion. In this study, a data set including a visual perception and an imagery experiment with human participants was used to train 2 types of voxel-wise encoding models. These models were based on Gabor features and voxel activity patterns of high-level visual cortex (i.e., fusiform face area, parahippocampal place area, and lateral occipital complex) to predict activity in the early visual cortex (EVC, i.e., V1, V2, V3) during perception, and then tested with respect to the generalization of these models to mental imagery. Our results showed that during perception and imagery, activities in the EVC could be independently predicted by the Gabor features and activity of high-level visual cortex via voxel-wise encoding models, which suggested that perception and imagery might share neural representation in the EVC. We further found Gabor-specific and non-Gabor-specific patterns of neural response to stimuli in the EVC, which were shared by perception and imagery. These findings provide insight into the mechanisms of how visual perception and imagery share representation in the EVC.

Abstract: Visual orthographic deficits have been reported as one of the core deficits in reading disability (RD), however, whether the deficits are orthographic-specific or domain general in all visual processing is still in debate. Hereby, we conducted an fMRI and an EEG study to examine visual orthographic deficits in Chinese adults with RD. In the fMRI study, we found that there was reduced brain activation in the left inferior temporal gyrus and right cuneus gyrus in orthographic processing (lexical minus perceptual), but not in visual perceptual processing (perceptual minus null) in adults with RD, suggesting orthographic-specific deficits. In the EEG study, adults with RD showed typical visual binding as indicated by intermodulation SSVEPs (steady-state visual-evoked potentials) for both real and pseudo characters, suggesting normal neural phase locking in the visual modality. These results consistently suggest orthographic specific deficits but normal visual perceptual processing in adults with RD, deepening our understanding of the underlying deficits associated with RD.

Abstract: People with multiple sclerosis (pwMS) report many different visual complaints, but not all of them are well understood. Decline in visual, visuoperceptual and cognitive functions do occur in pwMS, but it is unclear to what extend those help us understand visual complaints. The purpose of this cross-sectional study was to explore the relation between visual complaints and decline in visual, visuoperceptual and cognitive functions, to optimize care for pwMS. Visual, visuoperceptual and cognitive functions of 68 pwMS with visual complaints and 37 pwMS with no or minimal visual complaints were assessed. The frequency of functional decline was compared between the two groups and correlations were calculated between visual complaints and the assessed functions. Decline in several functions occurred more frequently in pwMS with visual complaints. Visual complaints may be an indication of declined visual or cognitive functioning. However, as most correlations were not significant or weak, we cannot infer that visual complaints are directly related to functions. The relationship may be indirect and more complex. Future research could focus on the overarching cognitive capacity that may contribute to visual complaints. Further research into these and other explanations for visual complaints could help us to provide appropriate care for pwMS.

Abstract: In natural environments objects comprise multiple features from the same or different sensory modalities but it is not known how perception of an object is affected by the value associations of its constituent parts. The present study compares intra- and cross-modal value-driven effects on behavioral and electrophysiological correlates of perception. Human participants first learned the reward associations of visual and auditory cues. Subsequently, they performed a visual discrimination task in the presence of previously rewarded, task-irrelevant visual or auditory cues (intra- and cross-modal cues, respectively). During the conditioning phase, when reward associations were learned and reward cues were the target of the task, high value stimuli of both modalities enhanced the electrophysiological correlates of sensory processing in posterior electrodes. During the post-conditioning phase, when reward delivery was halted and previously rewarded stimuli were task-irrelevant, cross-modal value significantly enhanced the behavioral measures of visual sensitivity, whereas intra-modal value produced only an insignificant decrement. Analysis of the simultaneously recorded event-related potentials (ERPs) of posterior electrodes revealed similar findings. We found an early (90–120 ms) suppression of ERPs evoked by high-value, intra-modal stimuli. Cross-modal stimuli led to a later value-driven modulation, with an enhancement of response positivity for high- compared to low-value stimuli starting at the N1 window (180–250 ms) and extending to the P3 (300–600 ms) responses. These results indicate that sensory processing of a compound stimulus comprising a visual target and task-irrelevant visual or auditory cues is modulated by the reward value of both sensory modalities, but such modulations rely on distinct underlying mechanisms.

Abstract: Alpha is the strongest electrophysiological rhythm in awake humans at rest. Despite its predominance in the EEG signal, large variations can be observed in alpha properties during development, with an increase of alpha frequency over childhood and adulthood. Here we tested the hypothesis that these changes of alpha rhythm are related to the maturation of visual white matter pathways. We capitalized on a large dMRI-EEG dataset (dMRI n=2,747, EEG n=2,561) of children and adolescents of either sex (age range: 5-21 years old) and showed that maturation of the optic radiation specifically accounts for developmental changes of alpha frequency. Behavioral analyses also confirmed that variations of alpha frequency are related to maturational changes in visual perception. The present findings demonstrate the close link between developmental variations in white matter tissue properties, electrophysiological responses, and behavior. Significance statement The present work shows that the maturation of visual white matter pathways (optic radiations) specifically accounts for the developmental increase of brain oscillations frequency (alpha), which is ultimately related to an enhancement of visual perception during childhood and adolescence. The present findings are an example of how relating white matter properties to functional aspects of the brain can help us reach a more complete understanding of the link between development of brain connectivity, changes in electrophysiology, and visual perception.