Biology subjects

Koevoet, D.

Publications and source records attributed to Koevoet, D..

7 recordsLinked to original sources

bioRxiv2026

Neural Encoding Geometry of Human Voluntary Visual Selection

Selecting relevant targets from competing alternatives is a core cognitive function. While human visual selection can be tracked with high spatiotemporal precision, it remains unsolved how selected targets and non-selected alternatives are neurally encoded to effectively separate them. Building on recent work revealing the neural encoding geometry underlying target selection in animals, we here examined how the representational format of selected targets and non-selected alternatives evolve over time during human voluntary selection. Initially, selected and non-selected objects showed equal spatially selective neural activity, yet the selected target was represented more strongly after 300-350 ms. Using cross-decoding, we found that selected and non-selected objects are encoded along a shared sensory axis, whereas selected targets are encoded along an additional spatially selective axis. This encoding geometry effectively separates selected targets from non-selected alternatives in neural space. Our results generalized across selection conditions: we found comparable results in instructed and free-choice selection, as well as in delayed oculomotor and covert visual selection. Together, we demonstrate that the human brain selectively encodes targets, but not distractors, along an additional axis, revealing a neural mechanism through which voluntary selection prioritizes behaviorally relevant information.

neuroscience↗

bioRxiv2026

Attentional selection is a neuroeconomic decision

Sensorimotor decisions require balancing extrinsic rewards against intrinsic action costs. How these signals are integrated during rapid eye-movement choices remains unclear. We show that human saccade selection follows cost-benefit computations consistent with neuroeconomic decision-making. Across two experiments, participants maximized rewards and minimized effort-costs. Reward titration revealed that more effortful saccades required higher monetary rewards to be chosen equally often. While effort-costs affected choices linearly, small reward differences shifted choices more than equally-sized larger ones. Furthermore, effort-cost (but not reward) differences regulated decision engagement: Deliberation was extended only when cost differences were large. Together, costs and rewards play dissociable roles in saccade selection, positioning eye movements as a tractable model system for economic decision-making.

neuroscience↗

bioRxiv2026

Frontal P3 Potential as a Supramodal Marker of Imminent Attentional Lapses

Focusing on an organisms task at hand is instrumental for intelligent and goal-driven behavior. However, humans and other animals often fail to pay sustained attention across long time intervals. Failing to stay on-task may cause one to miss crucial task-relevant signals, leading to impaired performance, which can have serious consequences. Therefore, it is important to understand the neural basis of attentional lapses. One promising neural marker of attentional lapses is the frontal P3 (fP3) EEG component, which has been suggested to reflect the susceptibility to incoming sensory input. Following this, we hypothesized that the fP3 1) predicts imminent lapses of attention, and 2) that it should predict upcoming lapses of attention across modalities. In two experiments, we found that the fP3 reliably tracked lapses of attention of sustained attention already seconds preceding the crucial visual signal. We further extended this to the auditory domain: Already 1.5s ahead of the incoming auditory target, the fP3 revealed whether that target was detected or not. Detailed topographic analyses did, however, reveal a slight dissociation between modalities in underlying intracranial source configurations. In sum, this work revealed a supramodal neural signature of susceptibility, which tracks lapses of sustained attention seconds ahead of the critical incoming sensory input.

neuroscience↗

bioRxiv2025

Visual working memory precision is under voluntary control

Visual working memory allows us to guide behavior based on recently seen information. Most research builds on the assumption that people always try to store visual information as precisely as possible, regardless of what the upcoming action requires. In everyday life, however, different (memory-guided) actions demand different levels of precision. Here we asked whether people flexibly adjust how deeply they encode, how much effort they put in maintaining visual information based on the task demands. Across three experiments participants memorized up to four colors, while we manipulated the required precision for a delayed report to be considered correct. We found that when required precision was higher, reports became slower and (in some cases) more precise. Crucially, we found that higher precision demands led to (1) stronger pupil constriction during encoding, indicating deeper encoding, and (2) larger pupil dilation during maintenance, indicating greater cognitive effort. Moreover, this adaptive increase in maintenance effort occurred not only when precision demands were known before encoding (Experiments 1 and 2), but even when they were revealed only after encoding (Experiment 3). Thus, the maintenance of visual information can be flexibly tuned in response to changing task demands. Yet, this flexibility had limitations: with increasing precision requirements, participants increased effort even when it no longer improved performance. Together, these findings show that visual working memory is not a passive store that is always maximally loaded. Instead, how visual information is encoded, maintained, and used is tuned to the demands of upcoming behavior.

neuroscience↗

bioRxiv2025

Population-Level Activity Dissociates Preparatory Overt from Covert Attention

The neural signatures of preparing overt eye movements and directing covert spatial attention overlap as they recruit the same brain areas. Yet, these neural signatures are dissociable at the single-cell level: Specific cells within visuo-oculomotor areas are exclusively involved in motor preparation or covert attention. Nevertheless, it has been proposed that many cells in visuo-oculomotor areas are involved in both motor preparation and covert attention, and consequently their neural signatures should functionally overlap to a large degree. Here, we directly tested this proposal: we combined human (both sexes) EEG with sensitive decoding techniques to investigate whether the neural signatures of preparatory overt and covert attention are dissociable across large-scale neuronal populations. We found that neural decoding reliably discerned whether overt or covert attention was shifted well before saccade initiation. Further, inverted encoding modeling revealed earlier and sharper spatially-tuned activity in preparatory overt than in covert attention. We then asked whether preparatory overt attention achieved sharper spatially-tuned activity by using more-of-the-same covert attention, or by recruiting additional spatially selective neural processing. Cross-decoding results demonstrated that preparatory overt attention recruited at least one additional, frontal process. This additional spatially selective process emerged early and likely reflects motor preparation or predictive remapping. To summarize, we found that the neural signatures of overt and covert attention overlap, yet diverge rapidly, in part because overt attention employs an additional spatially selective neural process. Extending beyond a dissociation on the single-cell level, our findings demonstrate that population-level neural activity dissociates preparatory overt from covert attention. Significance statementThe world provides much more visual input than the brain can process simultaneously. Spatial visual attention allows for the selective processing of only the most important parts of this input. Spatial attention shifts either overtly (with an eye movement) or covertly (without an accompanying eye movement). The neural signatures underlying these types of spatial attention have long thought to overlap to a large degree. This strong overlap was thought to only break down at the level of single neurons. In our EEG study, we instead demonstrate that large populations of neurons dissociate overt from covert attention. Our results show that the neural signatures of overt and covert attention differ on a much broader scale than previously thought.

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↗