Biology subjects

Naber, M.

Publications and source records attributed to Naber, M..

5 recordsLinked to original sources

bioRxiv2026

Visual Attention doesnt Travel, it Teleports

Attention forms a key, yet elusive component of visual processing. We shift attention constantly across the visual field to enhance processing of relevant locations or stimuli in service of goal-directed behavior. Here, we investigate a fundamental property of attentional shifts: when covertly shifting from one location to another, does visual attention "travel" (enhance processing at intermediate locations) or "teleport" (not interact with intermediate locations)? While most shifts of information or movement "travel" (e.g., eye and body movements, neuronal signalling), for attentional shifts such intermediate processing enhancement might not be necessary, nor functional. To answer this question while tackling the difficulty of tracking covert attentional dynamics, we conducted an EEG-eyetracking experiment (n=24) paired with Rapid Invisible Frequency Tagging (RIFT). This let us track attentional enhancement during covert attentional shifts with high temporal and spatial precision. We successfully registered covert shifts, but found no evidence for any attentional modulation in-between the start and end-point of an attentional shift. Additional insilico modelling of attentional shifts confirmed that our method was sensitive enough to pick up on these modulations had they been present. Our results support a "teleporting" model of attention, suggesting that attention is implemented in a fundamentally different manner compared to overt visual behaviours such as eye movements.

neuroscience↗

bioRxiv2026

Luminance-corrected Pupillometry for Reliable Effort-tracking in Dynamic Environments

Pupillometry provides an objective way to index effort across domains. However, pupil size is strongly affected by luminance changes, which can obscure effort-related effects, and limit its use in most applied scenarios with dynamic visual input. We here introduce and validate a method to overcome this problem. To this end, participants performed an auditory n-back task of differing difficulty while viewing either constant visual input or dynamic driving movie clips. Effort was assessed physiologically (pupil size), behaviorally (accuracy), and subjectively (NASA-TLX). Accuracy, questionnaire scores, and pupil size were analyzed at the session level, while pupillometry additionally provided continuous time-resolved information. As expected, pupillometry tracked differences in effort, but its discriminability was substantially reduced under dynamic visual input. Correcting for the effects of overall luminance and moment-to-moment luminance changes using a dynamic, explainable, and open-source modeling procedure (Open-DPSM) considerably improved effort discriminability on both aggregate and time-resolved levels. At the aggregate level, luminance-corrected pupillometry slightly outperformed accuracy and NASA-TLX. Combining all three measures yielded the highest classification performance (AUC = 0.98), supporting the view that effort is multifaceted and best captured multimodally. These findings establish a practical basis for fine-grained physiological tracking of effort and arousal in both fundamental and applied research using complex, dynamic stimuli. A tutorial section guides researchers in applying luminance correction to their own pupillometric data in dynamic viewing environments using the here validated approach.

neuroscience↗

bioRxiv2024

Effort Drives Saccade Selection

What determines where to move the eyes? We recently showed that pupil size, a well-established marker of effort, also reflects the effort associated with making a saccade (saccade costs). Here we demonstrate saccade costs to critically drive saccade selection: when choosing between any two saccade directions, the least costly direction was consistently preferred. Strikingly, this principle even held during search in natural scenes in two additional experiments. When increasing cognitive demand experimentally through an auditory counting task, participants made fewer saccades and especially cut costly directions. This suggests that the eye-movement system and other cognitive operations consume similar resources that are flexibly allocated among each other as cognitive demand changes. Together, we argue that eye-movement behavior is tuned to adaptively minimize saccade-inherent effort.

neuroscience↗

bioRxiv2024

Sensory Input Matching Visual Working Memory Guides Internal Prioritization

Adaptive behavior necessitates the prioritization of the most relevant information in the environment (external) and in memory (internal). Internal prioritization is known to guide the selection of external sensory input, but the reverse may also be possible: Does the environment guide the prioritization of memorized material? Here we addressed whether reappearing sensory input can facilitate the prioritization of other non-reappearing memorized items held in visual working memory (VWM). Participants (total n = 96) memorized three orientations. Crucially some, but not all, items maintained in VWM were made available again in the environment. These reappearing items never had to be reproduced later. Experiment 1 showed that the reappearance of all but one memory item benefited accuracy and speed to the same extent as a spatial retro cue. This shows that reappearing items allow for the dynamic prioritization of another non-reappearing memorized item. What aspects of the reappearing sensory input drive this effect? Experiments 2-4 demonstrated that prioritization was facilitated most if reappearing items matched VWM content in terms of both location and orientation. Sensory input fully matching VWM is possibly processed more efficiently and/or protects against interference, ultimately leading to stronger prioritization of other memory content. We propose that the link between sensory processing and VWM is bidirectional: internal representations guide the processing of sensory input, which in turn facilitates the prioritization of other VWM content to subserve adaptive behavior. All data and analysis scripts are available here: https://osf.io/qzvkc/.

neuroscience↗

bioRxiv2019

Adaptation to transients disrupts spatial coherence in binocular rivalry

When the two eyes are presented with incompatible images, the visual system fails to create a single, fused, coherent percept. Instead, it creates an ongoing alternation between each eyes image; a phenomenon dubbed binocular rivalry (BR). Such alternations in awareness are separated by brief, intermediate states during which a spatially mixed (incoherent) pattern of both images is perceived. A recent study proposed that the precedence of mixed percepts positively correlates with the degree of adaptation to conflict between the eyes. However, it neglected the role of visual transients, which covaried with the degree of conflict in the stimulus design. We here study whether the presence of visual transients drive adaptation to interocular conflict and explain incidence rates of spatially incoherent BR. Across three experiments we created several adaptation conditions in which we systematically varied the frequency of transients and the degree of conflict between the eyes. Transients consisted of grating orientation reversals, blanks, and plaids. The results showed that the pattern of variations in the fractions mixed percepts across conditions was best explained by variations in the frequency of visual transients, rather than the degree of conflict between the eyes. We propose that the prolonged presentation of transients to both eyes evokes a chain of events consisting of (1) the exogenous allocation of attention to both images, (2) the increase in perceptual dominance of both rivalling images, (3) the speed up of adaptation of interocular suppression, and eventually (4) the facilitation of mixed perception during BR after adaptation. Author summaryWhen one eye is presented with an image that is distinct from the image presented to the other eye, the eyes start to rival and suppress each others image. Binocular rivalry leads to perceptual alternations between the images of each eye, during which only one of the images is perceived at a time. However, when the eyes exert weak and shallow mutual suppression, observers tend to perceive both images intermixed more often. Here we designed an experiment and a model to investigate how stereoscopic stimuli can be designed to alter the degree of interocular suppression. We find that prolonged and repeated observations of strong visual transients, such as sudden changes in contrast, can facilitate the adaptation to suppression between the eyes, resulting in that observers report more mixed percepts. This novel finding is relevant to virtual- and augmented reality for which it is crucial to design stereoscopic environments in which binocular rivalry is limited.

neuroscience↗