Biology subjects

Kaiser, D.

Publications and source records attributed to Kaiser, D..

At least 19 recordsLinked to original sources

bioRxiv2026

Familiarity synchronizes brain rhythms during natural viewing

Our perception of the world is shaped not only by sensory information, but also by prior experience. However, how familiarity alters the coordination of neural representations across distributed brain networks remains unclear. Rhythmic neural activity provides a potential mechanism for coordinating information across sensory and higher-order brain regions in the light of previous experience. Here, we thus investigated whether familiarity alters the coordination of brain rhythms during naturalistic viewing. Participants who were either familiar or unfamiliar with the television series Game of Thrones viewed clips from the series while EEG or fMRI was recorded. We calculated the intersubject correlations of neural activity across EEG frequency bands and related this rhythmic activity to fMRI BOLD responses. Across participants, all brain rhythms showed reliable intersubject synchrony and related to activity across large-scale brain networks. Familiarity selectively enhanced intersubject synchronisation in beta and gamma rhythms, with these effects reflected in visual and default mode brain regions. Moreover, beta and gamma band activity were modulated by similar aspects of the movie, suggesting coordinated familiarity-related processing. These findings show that familiarity selectively shapes rhythmic neural dynamics across the cortex, providing a mechanism through which prior experience alters the coordination of neural representations during naturalistic perception.

neuroscience↗

bioRxiv2026

Disrupting the Right Inferior Frontal Gyrus Increases Social Brain Activity During Emotion Recognition

Neuroimaging studies have identified a specialised social brain network that supports emotion recognition and social cognition. This network performs a range of functions that include facial expression recognition and inferring the mental states of others. Studies of neuropsychological patients report that damage to the right inferior frontal gyrus (IFG), the top-down control area in this network, impairs facial expression recognition. To investigate how transient disruption of the right IFG affects the wider social brain we combined transcranial magnetic stimulation (TMS) with functional magnetic resonance imaging (fMRI). Participants (n=20) were scanned across two sessions while performing a delayed match-to-sample emotion recognition task in which happy or fearful expressions were preceded by a congruent or incongruent word cue. Prior to each scan, thetaburst TMS was delivered over the right IFG or over the vertex control site (session order was balanced across participants). A group whole-brain analysis revealed that TMS to the IFG increased neural activity in multiple regions of the social brain network. These included the bilateral temporal pole, precuneus and medial prefrontal cortex (mPFC). This pattern of results shows that the disruption of top-down control mechanisms localised in the IFG alters the neural processing in remote nodes of the social brain network. Our findings are discussed within the wider context of how we recognise and understand the emotions of other people.

neuroscience↗

bioRxiv2026

Acceleration of vision changes object representations from infancy to adulthood

While much of the neural and cognitive machinery for visual perception is in place within weeks from birth, we identified and quantified a fundamental difference between infant and adult vision: the temporal rate at which meaningful visual information can be reliably extracted. Using frequency-tagging electroencephalography with rapid serial visual presentation, we found that object categorization at 4 and 9 months is respectively seven times and two to three times slower than in adults. Using quantitative information from infants experiments, we created and presented accelerated visual streams to adults, to match infants perceptual experience. We used deep convolutional neural networks to identify object representations that match those elicited in adults when accelerating the information flow. Results show that acceleration compromises finer-grained object distinction while sparing broad, general object representations. We propose that slow vision is a design feature of early development for preserving and highlighting the most stable and general features of the world.

neuroscience↗

bioRxiv2026

Early EEG responses indicate liking for artworks presented in rapid visual streams

When we appreciate visual art, we often take our time: We visit museums or galleries and deliberately engage with artworks and their meaning. Yet, our liking might at least partly be shaped by incidental encoding of the artworks' visual features, a process initially independent from sustained engagement. Here, we show that liking for visual art can be predicted from rapid and automatic responses in the visual brain. We recorded EEG responses while participants viewed 999 artworks from the Vienna Art Picture System (VAPS), which features complex artworks that span different categories and art styles. Artworks were shown with a 300ms stimulus-onset-asynchrony (150ms on, 150 off), and participants responded to occasional target images. Using representational similarity analysis, we predicted the geometry of neural representations from the artworks' similarity in liking (based on ratings from a different group of observers), while simultaneously controlling for similarities in other properties (category, art style, valence, arousal, and familiarity). Crucially, neural responses emerging within the first 150ms were robustly connected to liking, even though the task did not afford any liking judgments. Strikingly, this early neural correlate of liking was also observed in a second experiment, in which we presented the same 999 artworks with a 50ms stimulus-onset-asynchrony. Our results show that even under ultra-fast presentation conditions, automatic neural responses rapidly indicate liking. While fully appreciating an artwork may still need deliberate and prolonged engagement, the perceptual basis of whether we like or dislike an artwork seems to be laid in a split second.

neuroscience↗

bioRxiv2026

A neuro-computational approximation of the qualities of mental images

Mental images are challenging to study, given that our conscious experience is notoriously hard to access. The currently prevalent introspective methods are inherently subjective and can thus only provide limited access to their qualities. Here, we developed a neuro-computational approach that approximates and assesses the properties of mental images without the need for introspection. To enable this approach, we collected a large-scale EEG dataset (10 participants, 10 sessions each, 43,200 trials total) of participants imagining 16 scenes based on text prompts. We employed AI image generation to create candidate image sets that approximate the content of mental images (based on the imagined text prompts), computationally simulated visual cortex responses to these images and then assessed their representational alignment with rhythmic EEG responses during imagery. In line with previous reports, mid- to high-level features of the AI-generated candidate images yielded reliable alignment with human alpha activity. By manipulating the qualities of the candidate images, we then tested which qualities predisposed higher representational alignment with cortical imagery representations. We found an increased representational alignment for spatially blurred and low contrast images, providing evidence for the prevalent notion of a reduced sensory quality of mental images. We further found that mental imagery may be characterized by a psychedelic image style, which envelops the images in visual flows that distort the image proportions. These results show that our approach can objectively capture qualities of mental images without the need of introspection, providing a hypothesis-based alternative to emerging reconstruction approaches.

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bioRxiv2026

Cortical alpha rhythms predictively track occluded motion trajectories

Objects in the real world frequently move along complex, non-linear trajectories shaped by their environment. As they do, they often pass temporarily out of sight, occluded by the surrounding environment. Yet humans can maintain representations of object position and motion even when objects are no longer visible. Here, we investigate the neural basis of tracking objects undergoing non-linear, environmentally constrained motion during occlusion. We recorded EEG while participants mentally tracked the position of a ball falling through differently curved pipes (Pipe condition). The pipe condition was compared to conditions in which only the ball trajectory was visible (Ball-only condition) or in which the pipe was completely covered by an occluder (Occluder condition). On occasional probe trials, the video was terminated at randomized time points and participants had to indicate the ball's last position using the mouse cursor. Behaviorally, participants systematically reported the ball ahead of its true position, with the strongest forward displacement in the occluded conditions. Neurally, multivariate decoding analysis on the EEG data revealed that alpha-band activity carried direction-specific motion information within and across conditions. Critically, cross-condition decoding revealed shared representations between perceived (Ball-only) and mentally tracked (Occluder) motion with representations in the occluder condition anticipating later representations in the ball-only condition. Together, our behavioral and neural findings provide convergent evidence that during non-linear motion tracking under occlusion, the brain codes object motion ahead of its current position, an 'ahead of time' strategy that may underlie temporal precision when tracking objects in a dynamically changing world.

neuroscience↗

bioRxiv2026

Distinct spatiotemporal representations of image beauty and image quality

Humans rapidly assess the beauty of natural scene images. Previous EEG work suggests neural representations of beauty emerge early and are temporally sustained. Complementary fMRI work pinpoints the neural correlates of beauty to visual, frontal, and default-mode network areas. An integrated view of the spatiotemporal dynamics that give rise to the perception of beauty, however, is lacking. Beyond the beauty of the depicted scene, the quality of the image itself influences its perceived beauty, and it is unknown how the brain separates these two factors. To address these questions, we recorded EEG (N = 52) and fMRI (N = 29) data while participants rated the beauty of 100 natural scene photographs. Another group of participants (N = 46) rated the image quality of the same photographs. Separate representational similarity analyses on the EEG and fMRI data revealed early and sustained beauty-related representations across widespread cortical areas. In contrast, representations of image quality emerged earlier, had markedly different representational dynamics, and were predominantly localized to visual cortex. In a model-based EEG-fMRI fusion analysis, we investigated how the correspondence between temporally resolved EEG signals and spatially resolved fMRI signals is explained by beauty ratings. Our results suggest that beauty-related representations emerge early (from around 165ms and peaking at 275ms post-onset), are long-lasting, and primarily originate from high-level visual cortex. This spatiotemporal signature persisted when controlling for image-quality ratings. Our findings emphasize the importance of perceptual processing for perceived beauty and suggest that the brain represents aesthetic appeal independently of image quality.

neuroscience↗

bioRxiv2026

Benefits and costs of contextual associations between real-world objects in the attentional blink

The attentional blink is a well-known phenomenon illustrating the limitations of human attention: When two visual targets are presented in rapid succession, identification of the second target is often impaired. While the attentional blink is known to attenuate when targets share perceptual features or category membership, real-world objects are also linked through contextual associations, shaped by objects typically occurring within the same environments. Here, we devised an attentional blink experiment in which we orthogonally manipulated contextual and categorical relationships between the two targets while controlling for their perceptual similarity. As the key result, contextual associations facilitated identification of the second target but impaired identification of the first target. These findings suggest that contextual associations yield distinct benefits and costs for visual cognition, where enhanced attentional access to subsequent targets is traded off against increased interference between targets.

neuroscience↗

bioRxiv2026

Primate visual cortex spontaneously computes the beauty of objects

During everyday vision, beauty is a spontaneous experience. Perceived beauty varies substantially across object categories: We find puppies more beautiful than moths and roses more beautiful than potatoes. Here, we provide evidence that early processing in human and non-human primate visual cortex already reflects perceived beauty, even without deliberate judgments of beauty. First, in a combined EEG-fMRI analysis, we show that beauty ratings for hundreds of object categories from the THINGS database are predicted from neural responses measured in separate groups of human participants viewing the same images without explicit beauty judgments. Beauty-related representations emerged in occipital visual cortex within 100ms and peaked around 130ms. Second, multi-unit activity in macaque visual cortex also predicted human beauty judgments, despite the animals highly limited knowledge of the objects. These results indicate a perceptual basis for the beauty of visual categories, which may underlie spontaneous preference formation in everyday situations. TeaserEarly visual areas in both human and non-human primates rapidly compute the beauty of real-world objects

neuroscience↗

bioRxiv2026

From pixels to pleasure: visual features explain dynamic aesthetic experiences across distinct movie content

Aesthetic experiences in everyday life unfold under continuously changing visual input. Although these experiences clearly depend on the observer and context, they are partly explained by the visual features of the input. Here, we investigated how well a combination of visual features predicts dynamic aesthetic experiences during naturalistic and artistic movie watching. In two experiments, participants continuously rated the aesthetic appeal of either the nature documentary Home or the animated art-style movie Loving Vincent. We modeled moment-to-moment ratings using image-computable visual features extracted from each movie frame, including visual fluency, color and motion statistics, and symmetry. Linear models trained on these features reliably predicted aesthetic ratings for new movie parts, both within and across observers, pointing to shared perceptual influences on aesthetic experiences. Model comparisons showed that visual fluency and color-related features were most informative for predicting aesthetic experience in both movies. Critically, models trained on one movie could reliably predict aesthetic appeal ratings in the other movie, despite the movies remarkably different content and styles. Color features were most informative for cross-movie prediction. We conclude that visual features shape dynamic and naturalistic aesthetic experiences, and that the mapping of visual features onto aesthetic appeal is stable across observers and different movie content.

neuroscience↗

bioRxiv2026

Can Individual Internal Models Predict Idiosyncratic Scene Exploration?

Each individual person looks at natural scenes in their own unique way, resulting in a distinct perceptual experience of the world. However, little is known about why such differences in gaze emerge. Here, we test the hypothesis that idiosyncrasies in gaze behavior are predicted by inter-subject variations in internal models--expectations about how scenes typically look. In two experiments, we first characterized participants personal internal models by asking them to draw typical bathroom and kitchen scenes. Individual differences in these drawings were quantified using an objective deep learning pipeline and, in turn, related to individual differences in gaze behavior. In Experiment 1, where participants freely viewed a set of kitchen and bathroom photographs, inter-subject similarities in internal models did not predict inter-subject similarities in gaze. In Experiment 2, we encouraged strategic exploration through gaze-contingent viewing and a memory task. Here, inter-subject similarities in internal models predicted similarities in fixation frequency and the sequence in which different object categories were inspected. These findings suggest that the influence of internal models on visual exploration is stronger under increased sensory uncertainty and when expectation-guided sampling of the environment is encouraged. Together, our results provide new insights into how individual expectations shape gaze behavior and help explain why people differ in how they explore the visual world.

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bioRxiv2026

Visual search is constrained by the variability of object-category templates

Real-world visual search is often performed at the category level: we search for shoes or bags without knowing their exact features in advance. This requires categorical search templates that accommodate the inherent variability within the target category. Here, we examine how the variability in search templates across categories constrains visual search performance. We quantify template variability by measuring variability in object drawings from a large online dataset (Experiment 1) and from a controlled lab-based drawing task (Experiment 2) and in turn relate this variability to performance in categorical search. Across both experiments, higher category variability, and thus broader search templates, were associated with slower responses. Moreover, the observers most prioritized object template predicted their search performance better than other observers templates, indicating that individual differences in template variability shape visual search. Together, our findings demonstrate that naturalistic visual search is governed by structured variability across both object categories and observers.

neuroscience↗

bioRxiv2026

Shared gaze reflects shared aesthetic experiences

When individuals view the same visual input, they often differ in their aesthetic appeal judgments, yet why people differ remains largely unclear. Here, we tested whether individual differences in aesthetic experience are linked to differences in visual exploration. In two experiments, participants watched the documentary "Home" while their eye movements were recorded. In Experiment 1, participants continuously rated aesthetic experience throughout the movie, whereas in Experiment 2, they watched the first half without a task and rated aesthetic experience only during the second half. Inter-individual similarity in gaze patterns, assessed using fixation heatmaps across time, predicted similarity in aesthetic appeal judgments in both experiments. Notably, in Experiment 2, gaze similarity during free viewing in the first half of the movie predicted similarity in aesthetic ratings during the second half, indicating that incidental eye movement patterns predict aesthetic experiences. Together, these results show that shared gaze patterns are linked to shared aesthetic experiences under naturalistic, dynamic viewing conditions.

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bioRxiv2026

Prior Scene Context Shapes the Neural Dynamics of Face Detection

Detecting faces in our surroundings typically only takes a fraction of a second. How can such a rapid perceptual process still be influenced by prior expectations? Here, we used electroencephalography (EEG) to investigate how prior scene context modulates the temporal dynamics of neural face representations. Participants viewed natural scenes containing a single face (left or right), each preceded by either a faceless version of the same scene (preview condition) or a gray screen (no-preview condition), while performing a face detection task. Using multivariate decoding, we found that face location could be decoded shortly after target onset. Critically, decoding accuracy was higher in the preview condition at early stages, whereas the no-preview condition showed higher decoding at later time points, suggesting rapid facilitation by prior context followed by compensatory processing when contextual information was absent. In contrast, time-frequency decoding revealed a sustained preview advantage across alpha, beta, and gamma bands, even during time periods when evoked responses favored the no-preview condition. This dissociation between evoked and induced neural signals indicates that prior scene context engages distinct neural processes: early evoked activity reflects rapid contextual facilitation of sensory representations, while induced oscillatory activity may support prolonged context-dependent modulation. Together, these results show how prior scene context and sensory-driven processing jointly shape rapid face perception through temporally and spectrally distinct neural dynamics. Significance StatementScientists studying perception have long investigated how the brain combines incoming sensory input with prior knowledge and expectations. Very fast perceptual decisions, however, are often assumed to rely primarily on sensory input alone. Here, we show that prior scene context shapes the neural processing of faces even during rapid face detection. When observers had prior information about a scene, neural representations of face location emerged earlier and followed a different temporal profile than when no contextual information was available. These findings demonstrate that even rapid face detection reflects an interaction between sensory-driven and context-dependent processes, and that prior knowledge influences perception through multiple, temporally distinct neural mechanisms.

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bioRxiv2026

Temporal Dynamics of EEG Decoding for Continuously Changing Visual Stimuli

Multivariate analyses of M/EEG data are typically performed on neural responses time-locked to discrete stimulus onsets. Such designs usually reveal high decoding performance during the initial transient response (0-500 ms), which subsequently drops to a lower, sustained level. Here, we examined time-resolved EEG decoding of natural scene processing when scenes gradually enter the visual field without a clear onset. We created video sequences in which one scene category (e.g., a beach) smoothly transitioned into another category (e.g., a forest) by blending images from two categories into a single composite panorama and moving a square aperture across it. We then compared EEG decoding for the first scenes within the transitions, which appeared with a sudden onset, to the second scenes, which emerged gradually as the videos progressed. For the first scenes, we observed robust category decoding from 60 ms after onset with a clear peak structure. For the second scene, category decoding was markedly weaker and showed no discernable peak structure. Realigning the appearance of category-diagnostic content for the second scene using deep neural networks did not enhance decoding or recover a peak structure. Further, classifiers trained on the first scene generalized to the second, but with a broad, temporally diffuse pattern, indicating that the second scene did not engage the same hierarchical temporal cascade as the first. Together, these results demonstrate that sudden versus gradual onsets produce distinct temporal decoding dynamics. Insights from onset-based decoding studies, therefore, do not straightforwardly extend to continuous and free-flowing natural stimulation.

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bioRxiv2025

Contextual associations impact visual search across multiple processing stages

Growing evidence indicates that visual search is influenced not only by perceptual but also by semantic information. Among such semantic influences, categorical effects have been extensively studied. By contrast, the influence of contextual associations, that is, how objects commonly co-occur within specific scene contexts, remains less understood. Here, we orthogonally manipulated contextual and categorical relationships between target and distractor objects in a visual search task, while controlling for perceptual target-distractor similarity. By applying linear regression analyses, we modelled behavioral responses and event-related potentials (ERPs) from contextual, categorical, and perceptual target-distractor similarity. We found that contextual associations guide attention by interacting with categorical information (modulating the N2pc) and ultimately shape behavioral search performance jointly with perceptual and categorical similarity. These findings demonstrate that contextual object associations can guide attention, thereby supporting efficient search in complex visual environments.

neuroscience↗

bioRxiv2025

Clinical development of gene edited tacrolimus-resistant Treg (FKBP12KO-Treg) to enable simultaneous immunosuppression and support of immune regulation

Background: Unwanted immune responses play a central role in the pathogenesis of solid organ allograft rejection. These are managed by life-long immunosuppression with considerable burden for the patient and society. Adoptive therapy with regulatory T-cells (Treg) is a promising approach to restore sustainable immune balance and avoid long-term adverse effects of immunosuppression. While Treg effectively inhibit activation of unwanted immune responses, they are less effective in controlling pre-existing/activated memory effector T-cells (Teff). Thus, co-administration of Treg with immunosuppressants is required to achieve a sustainable organ acceptance. Calcineurin inhibitors (CNI) are powerful in controlling de novo generated and preformed Teff. However, CNI also dampen Treg immunoregulatory function. Thus, we hypothesize improved results of adoptive Treg therapy in immunosuppressed patients applying tacrolimus-resistant Treg. Methods: While retaining CNI modulation of Teff with tacrolimus, we knocked-out FKBP12 in Treg (FKBP12KO-Treg) by gene-editing using ribonucleoprotein-based CRISPR/Cas9 technology to generate tacrolimus-resistant Treg and characterised them using flow cytometry, functional assays and in-depth phenotyping. Results: This detailed in vitro analysis showed FKBP12KO-Treg were comparable to non-gene edited Treg and impervious to tacrolimus while maintaining immunoregulatory function and sensitivity to alternative CNIs raising no safety concerns. Furthermore, we aligned our methodology to achieve GMP compliance laying the basis for a manufacturing license in preparation of a clinical trial. Conclusion: Based on the presented preclinical dataset implying safety and efficacy of FKBP12KO-Treg, we are now seeking to undertake a proof-of-concept clinical trial to evaluate the co-administrationof FKBP12KO-Treg and tacrolimus to enhance the management of living donor kidney transplant recipients.

immunology↗

bioRxiv2025

Distinct Mechanisms of Surround Modulation for Dynamic Natural Scenes in Motion- and Scene-Selective Cortex

Surround modulation refers to changes in neural responses to a central stimulus induced by its surrounding context, which can manifest as either suppression or facilitation. Although this phenomenon is well established for simple stimuli, its underlying neural mechanism during natural scene perception remains unclear. Using fMRI, we examined how motion congruence and categorical similarity between central and surrounding scenes shape surround modulation across the visual hierarchy. Central and surrounding scenes systematically varied in categorical similarity (identical exemplar, different exemplar of the same basic-level category, different basic-level category, or different superordinate category) and in motion direction (same or opposite direction). Neural responses were measured in primary visual cortex (V1), motion-selective cortex (hMT+), and scene-selective occipital and parahippocampal place areas (OPA and PPA). hMT+ showed robust motion-dependent surround suppression, which was stronger for same-direction motion. In contrast, V1 showed surround facilitation across all conditions, which was reduced when center and surround were identical and moved in the same direction, consistent with sensitivity to physical similarity. OPA and PPA primarily exhibited facilitation. Multivariate decoding between center-only and center-surround conditions complemented these findings, revealing motion-dependent surround modulation in hMT+, and category-dependent surround modulation in OPA and PPA. Across the visual hierarchy, surrounding scene context thus systematically attenuates redundant input or enhances informative differences: from low-level facilitation in V1 to motion-dependent suppression in hMT+ and category-dependent modulation in scene-selective regions.

neuroscience↗