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van Ede, F.

Publications and source records attributed to van Ede, F..

At least 19 recordsLinked to original sources
bioRxiv2026

Distinct working-memory organisation for the colour and duration of visual objects

When holding information 'in mind', it is essential that individual objects in working memory remain separated and accessible for guiding behaviour. Space is a well-established organising principle for retaining various features of visual objects in working memory, but whether this spatial organisation is universally applied across all features of visual objects remains unclear. Here, we tested whether two inherently non-spatial features of a visual item, colour and duration, rely on the same spatial organisation of working memory. To track this spatial organisation implicitly, we measured directional biases in microsaccades while participants were cued to select one of two memorised visual items in order to report either its colour or its duration, depending on the session. Crucially, while the visual stimuli were identical between the colour-report and the duration-report sessions, accessing colour information led to a robust spatial microsaccade bias towards the item's original location, whereas this bias was absent when accessing duration. This was corroborated by a significant difference in the spatial bias between the colour and duration sessions. We conclude that the memory organisation for colour and duration is distinct, even when memory regards the exact same visual objects. This implies that the spatial organisation of working memory for visual features is not universal, but feature-dependent.

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bioRxiv2026

Externally driven attention to internal working memory content

To understand human thought and behaviour, it is vital to understand how internal representations in mind interface with external sensations in the outside world. It is well-established that representations in working memory can involuntarily draw attention towards objects in the outside world with corresponding visual features. Here, we establish that this interface involves a two-way stream by demonstrating that external sensations also involuntarily draw attention to corresponding internal representations in working memory. We demonstrate this across four dedicated experiments in which an unpredictive external stimulus selectively colour-matched working-memory contents, while being completely irrelevant to the working-memory task. We provide converging evidence for this "externally driven internal attention" from tracking attentional dynamics over time through spatial biases in microsaccades as well as from memory performance. We further highlight that engagement with the external stimulus critically shapes the strength of this attentional capture from perception to memory. Together, our findings delineate the properties and consequences of this underexplored attentional pathway, opening novel avenues for research at the interface of perception and memory, and their disorders.

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bioRxiv2026

Proactive visual and motor prioritization differentially scale with cue reliability

Environmental cues enable the brain to anticipate and prepare for upcoming behavior, such as by selectively prioritizing relevant visual representations and associated action plans in working memory in service of an imminent task. While it has been demonstrated that neural dynamics of visual and motor prioritization each scale with cue reliability, studies to date tracked either visual or motor prioritization in isolation. It therefore remains unknown whether visual and motor prioritization scale similarly or differently with cue reliability. To fill this gap, we manipulated cue reliability (100%, 80%, 60%) in a visual-motor working-memory task that uniquely enabled us to isolate the neural dynamics associated with visual and motor prioritization in anticipation of an imminent working-memory task. EEG measurements in male and female human volunteers revealed how cue reliability differentially drives visual and motor prioritization. While the strength and timing of visual prioritization were relatively stable across cue reliability levels, motor prioritization profoundly scaled with cue reliability and developed more gradually with lower certainty. These findings show that visual and motor prioritization in working memory are differentially susceptible to the certainty conveyed by environmental cues, and suggest that motor prioritization may be more cautious in nature. Significance StatementTo cope with the ever-changing world, the human brain continuously leverages environmental cues to anticipate upcoming behavior, such as by prioritizing relevant visual representations and action plans in mind. Yet, in a volatile world, environmental cues typically vary in the certainty they provide. Building on prior work studying visual or action prioritization in isolation, we uniquely studied how cue certainty shapes both visual and motor prioritization within the same task. We unveil how cue certainty distinctly drives visual and action prioritization, with action prioritization requiring more certainty before deployment, whilst also being deployed more gradually at lower certainty. Thus, prioritization of potential actions is distinct from--and more cautious than--prioritization of the visual representations that guide these actions.

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bioRxiv2026

Exogenously driven neural reactivation of spatially matching visual working-memory contents

Selective attention is often divided into voluntary (goal-directed) and involuntary (stimulus-driven) forms, a distinction extensively studied for attention to external sensory input. In contrast, internal selective attention--directed toward representations held in working memory (WM)--has been considered primarily for voluntary influences. Recent behavioral evidence suggests that task-irrelevant external stimuli can also influence internal selection of feature-matching WM representations involuntarily, yet the neural mechanisms underlying these effects remain unclear. Here, we tested whether an uninformative exogenous spatial retro-cue presented during a WM delay can act as a selective "ping" and reactivate spatially matching WM content at the level of its representational category. Male and female human participants memorized complex contents presented at distinct locations, followed by unpredictive and task-irrelevant spatial retro-cues that conveyed no category information. Using temporally resolved multivariate EEG decoding, we observed category-specific reactivation of spatially matching WM representations following these cues, providing direct neural evidence for stimulus-driven, involuntary attentional selection within WM, ahead of the memory test. Moreover, neural responses to the subsequent memory-probe were also modulated by cue congruency, consistent with the notion that exogenous influences begin early during sensory processing while also shaping later decision-related processes. Finally, drift-diffusion model analyses revealed that this involuntary cueing effect was primarily driven by increased evidence accumulation. Together, these findings illuminate the mechanisms by which external events can automatically and involuntarily penetrate the internal cognitive workspace. Significance StatementThe processes underlying involuntary attentional selection of internal information held in our working-memory system have been largely overlooked. Our study shows that external stimuli can automatically select information that is temporarily held in our mind. We found that uninformative, task-irrelevant visual cues can selectively "ping" and reactivate specific working-memory contents, despite carrying only spatial information. We demonstrate that these cues trigger category-specific neural reactivation and shape later decision-making by accelerating evidence accumulation. This extends current knowledge on how the outside world can transiently interact with our internal cognitive workspace.

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bioRxiv2025

Transcranial magnetic stimulation induced pupil dilations can serve as a cortical excitability measure

The application of non-invasive brain stimulation (NIBS) often relies on proxy estimates of cortical excitability (CE), such as the resting motor threshold (rMT), measured through transcranial magnetic stimulation (TMS). However, estimating the rMT is not always possible, as it requires an intact corticospinal pathway for neural signals to travel from the cortex to the periphery. To broaden the application of NIBS there is a need for additional CE measures. In three experiments combining TMS, transcranial direct current stimulation (tDCS), and eye-tracking, we measured TMS-induced pupil dilations as a potential CE proxy. We present Bayesian evidence (Experiment 1: BF > 9; Experiment 2: BF > 46; Experiment 3: BFs > 6) that TMS-induced pupil dilations serve as an objective CE proxy, with larger pupil size reflecting higher CE. We also show that these effects are not due to auditory, muscle, or sensory confounds. The introduction of this novel measure paves the way for a deeper understanding of CE by enabling objective NIBS measures beyond the motor cortex. Moving away from the reliance on the motor cortex would allow NIBS research and therapy to become more inclusive, allowing access to populations that are affected by damage along the corticospinal pathway.

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bioRxiv2025

Microsaccades track shifting but not necessarily maintaining covert visual-spatial attention

Covert attention enables the brain to prioritise relevant visual information without directly looking at it. Ample studies have linked covert visual-spatial attention to the direction of small fixational eye movements called microsaccades, offering researchers and clinicians a potential non-invasive tool to track internal states of covert attention. However, other studies have reported only a weak link or no link at all. We now show that the link between covert visual-spatial attention and microsaccades critically depends on the stage of attentional deployment. Across two experiments--each employing a distinct but widely adopted approach to fixational control--we show that spatial microsaccade biases were more pronounced (Experiment 1) or even exclusively present (Experiment 2) during the initial stage of shifting covert spatial attention, even when covert attention was subsequently maintained as testified by enhanced visual discrimination. This shows that the involvement of the brains oculomotor system in covert visual-spatial attention qualitatively changes over the course of attentional deployment, and how its peripheral fingerprint in the form of microsaccades reliably indexes shifting but not necessarily maintaining covert visual-spatial attention. Significance statementCovert attention is essential for efficient processing of information from our surroundings. Several studies have linked covert attention to the direction of miniscule eye-movements known as microsaccades. Other recent studies have questioned this link. We now explain this discrepancy by treating attention not as a single static construct but as a dynamic process. We show that the link between microsaccades and covert attention critically depends on the stage of attention--with microsaccades robustly tracking shifting but not maintaining covert attention. This reveals how the contribution of the brains oculomotor system to attention changes dynamically over time. These findings have implications for the use of microsaccades as an accessible marker of attentional (mal)function across psychological and neurological conditions.

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bioRxiv2025

Anticipated action goals structure spatial organisation in visual working memory following self-movement

Working memory enables the retention of relevant visual information in service of anticipated behaviour. Consequently, the goal for which information is retained may crucially sculpt the way we retain and organise information in visual working memory. Here, we investigated how anticipated action goals structure the spatial organisation used for visual working memory following self movement. Participants encoded two tilted objects (left and right) in working memory, then turned around 180 degrees before being cued to either reproduce the tilt of the cued object from memory (report session) or manually reach back to it (reach session). The 180-degree self-movement uniquely enabled us to oppose and disentangle two potential spatial frames for immersive working memory in moving participants: the native spatial frame of how the objects were registered during encoding and an updated spatial frame keeping track where the objects are in the external world behind the participant after self-movement. Behavioural memory reports and spatial biases in gaze converged on the use of distinct spatial frames in the two tasks. This reveals how a foundational aspect of working memory in behaving humans - the spatial frame used to organise memories following self movement - is critically sculpted by anticipated action goals.

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bioRxiv2025

Concurrent selection of internal goals and external sensations during visual search

Flexible goal-directed behaviour relies on the selective processing of internal goal representations and external sensations. Yet, internal and external selection processes have classically been studied in isolation, leaving us in the dark how internal and external selection processes are coordinated in time to support behaviour. To address this, we developed a novel visual-search task in which we could simultaneously track selection among internal search goals held in working memory and external search targets in the environment. Capitalising on sensitive gaze and neural markers of internal and external visual selection, we provide proof-of-principle evidence in humans that internal and external selection processes do not necessarily take turns in a strictly serial manner, but can develop concurrently. We further show how concurrent internal and external selection processes are associated with largely non-overlapping neural activity patterns in the human brain, and how these processes can be performed effectively even when engaging opposite spatial locations in working memory and perception. These findings challenge views portraying brain states as being either internally or externally focused and bring new insight into how internal and external selection processes work together to yield efficient search behaviour.

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bioRxiv2024

Neural dynamics of reselecting visual and motor contents in working memory after external interference

In everyday tasks, we must often shift our focus away from internal representations held in working memory to engage with perceptual events in the external world. Here, we investigated how our internal focus is reestablished following an interrupting task by tracking the reselection of visual representations and their associated action plans in working memory. Specifically, we ask whether reselection occurs for both visual and motor memory attributes and when this reselection occurs. We developed a visual-motor working-memory task in which participants were retrospectively cued to select one of two memory items before being interrupted by a perceptual discrimination task. To determine what information was reselected, the memory items had distinct visual and motor attributes. To determine when internal representations were reselected, the interrupting task was presented at one of three distinct time points following the retro-cue. We employed electroencephalography time-frequency analyses to track the initial selection and later reselection of visual and motor representations, as operationalized through modulations of posterior alpha (8-12 Hz) activity relative to the memorized item location (visual) and of central beta (13-30 Hz) activity relative to the required response hand (motor). Our results showed that internal visual and motor contents were concurrently reselected immediately after completing the interrupting task, rather than only when internal information was required for memory-guided behavior. Thus, following interruption, we swiftly resume our internal focus in working memory through the simultaneous reselection of memorized visual representations and their associated action plans, thereby restoring internal contents to a ready-to-use state. Significance statementA key challenge for working memory is to maintain past visual representations and their associated actions while engaging with the external environment. Our cognitive system must, therefore, often juggle multiple tasks within a common time frame. Despite the ubiquity of multi-task situations in everyday life, working memory has predominantly been studied devoid of additional perceptual, attentional, and response demands during the retention interval. Here, we investigate the neural dynamics of returning to internal contents following task-relevant interruptions. Particularly, we identify which attributes of internal representations are reselected and when this reselection occurs. Our findings demonstrate that both visual and motor contents are reselected immediately and in tandem after completion of an external, interrupting task.

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bioRxiv2024

Dynamic prioritisation of sensory and motor contents in working memory

Internal selective attention prioritises both sensory and motor contents in working memory to guide prospective behaviour. Prior research has shown how attention modulation of sensory contents is flexible and temporally tuned depending on access requirements, but whether the prioritisation of motor contents follows similar flexible dynamics remains elusive. Also uncharted is the degree of co-dependence of sensory and motor modulation, which gets at the nature of both working-memory representations and internal attention functions. To address these questions, we independently tracked the prioritisation of sensory and motor working-memory contents as a function of dynamically evolving temporal expectations. The design orthogonally manipulated when an item location (left vs right side) and associated prospective action (left vs right hand) would be relevant. Contralateral modulation of posterior alpha (8-12 Hz) activity in electroencephalography (EEG) tracked prioritisation of the item location, while contralateral modulation of central mu/beta (8-30 Hz) activity tracked response prioritisation. Proactive and dynamic alpha and mu/beta modulation confirmed the flexible and temporally structured prioritisation of sensory and motor contents alike. Intriguingly, the prioritisation of sensory and motor contents was temporally uncoupled, showing dissociable patterns of modulation. The findings reveal multiple modulatory functions of internal attention operating in tandem to prepare relevant aspects of internal representations for adaptive behaviour.

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bioRxiv2024

Looking into working memory to verify potential targets during search

Finding what you are looking for is a ubiquitous task in everyday life that relies on a two-way comparison between what is currently viewed and internal search goals held in memory. Yet, despite a wealth of studies tracking visual verification behavior among the external contents of perception, complementary processes associated with visual verification among internal contents of memory remain elusive. Building on a recently established gaze marker of internal visual focusing in working memory, we tracked the internal-inspection process associated with confirming or dismissing potential targets during search. We show how we look back into memory when faced with external stimuli that are perceived as potential targets and link such internal inspection to the time required for visual verification. A direct comparison between visual verification among the contents of working memory or perception further revealed how verification in both domains engages frontal theta activity in scalp EEG, but also how mnemonic verification is slower to deploy than perceptual verification. This establishes internal verification behavior as an integral component of visual search, and provides new ways to look into this underexplored component of human search behavior.

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bioRxiv2024

Microsaccades strongly modulate but do not cause the N2pc EEG marker of spatial attention

The N2pc is a popular human-neuroscience marker of covert and internal spatial attention that occurs 200-300 ms after being prompted to shift attention - a time window also characterised by the spatial biasing of microsaccades. Here we show how co-occurring microsaccades profoundly modulate N2pc amplitude during the top-down deployment of spatial attention in both perception and working memory. At the same time, we show that a significant - even if severely weakened - N2pc can still be established in the absence of co-occurring microsaccades. Thus, while microsaccade presence and direction strongly modulate N2pc amplitude, microsaccades are not strictly a prerequisite for the N2pc to be observed.

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bioRxiv2024

Dynamics of attentional re-orienting in visual working memory following expected and unexpected memory tests

A classic distinction from the domain of external attention is that between anticipatory orienting and subsequent re-orienting of attention to unexpected events. Whether and how humans also re-orient attention in mind following expected and unexpected working-memory tests remains elusive. We leveraged spatial modulations in neural activity and gaze to isolate re-orienting within the spatial layout of visual working memory following central memory tests of certain, expected, or unexpected mnemonic content. Besides internal orienting after predictive cues, we unveil a second stage of internal attentional deployment following both expected and unexpected memory tests. Following expected tests, internal attentional deployment was not contingent on prior orienting, suggesting an additional verification - "double checking" - in memory. Following unexpected tests, re-focusing of alternative memory content was prolonged. This brings attentional re-orienting to the domain of working memory and underscores how memory tests can invoke either a verification or a revision of our internal focus.

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bioRxiv2024

Tracking how attentional focusing in working memory benefits long-term memory

Working memory serves as a key gateway to the formation of lasting memories. While it is established how attentional focusing during working memory prioritizes internal representations for imminent tasks, the dynamic processes by which such internal focusing affects subsequent long-term memory remain underexplored. We developed a two-stage visual working-memory/long-term-memory task in which we cued visual objects during working memory and tracked the dynamics of attentional deployment through a recently uncovered gaze marker of internal focusing. Across two experiments, we found that attentional focusing during working memory benefits subsequent long-term memory for internally attended objects without a cost to unattended objects. Gaze biases associated with internal focusing revealed how this benefit was supported by the speed of attentional deployment, with faster attentional deployment predicting better subsequent memory. These results highlight how attentional focusing in working memory benefits long-term memory, and uncover the dynamic processes that instill such lasting benefits.

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bioRxiv2024

Memory load influences our preparedness to act on visual representations in working memory without affecting their accessibility

It is well established that when we hold more content in working memory, we are slower to act upon specific content when it becomes relevant for behavior. Here, we asked whether slower responses with higher working-memory load can be accounted for by slower access to sensory representations held in working memory (according to a serial internal search), or by a lower preparedness to act upon them. To address this, we designed a visual-motor working-memory task in which participants memorized the orientation of two or four colored bars, of which one was cued for reproduction. We independently tracked the selection of visual (cued item location) and motor (relevant manual action) information from the EEG time-frequency signal, and compared their latencies between our memory-load conditions. We confirm slower memory-guided behavior with higher working-memory load and show that this is associated with delayed motor selection, but find no evidence for a concomitant delay in the latency of visual selection. Moreover, we show that variability in decision times within each memory-load condition is associated with corresponding changes in the latency of motor, but not visual selection. These results reveal how memory load affects our preparedness to act on, without necessarily changing the ability to access, sensory representations in working memory. This posits action readiness is a key factor that shapes the speed of memory-guided behavior and that underlies delayed responses with higher working-memory load.

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bioRxiv2024

Neural dynamics of shifting attention between perception and working-memory contents

In everyday tasks, our focus of attention shifts seamlessly between contents in the sensory environment and internal memory representations. Yet, research has mainly considered external and internal attention in isolation. We used magnetoencephalography to compare the neural dynamics of shifting attention to visual contents within vs. between the external and internal domains. Participants performed a combined perception and working-memory task in which two sequential cues guided attention to upcoming (external) or memorised (internal) sensory information. Critically, the second cue could redirect attention to visual content within the same or alternative domain as the first cue. Multivariate decoding unveiled distinct patterns of human brain activity when shifting attention within vs. between domains. Brain activity distinguishing within- from between-domain shifts was broadly distributed and highly dynamic. Intriguingly, crossing domains did not invoke an additional stage prior to shifting. Alpha lateralisation, a canonical marker of shifting spatial attention, showed no delay when cues redirected attention to the same vs. alternative domain. Instead, evidence suggested that neural states associated with a given domain linger and influence subsequent shifts of attention within vs. between domains. Our findings provide the first insights into the neural dynamics that govern attentional shifts between perception and working memory. Significance StatementDuring almost every natural behaviour, our attention regularly shifts between sensory and memory contents. Although the systems and mechanisms of attentional control and modulation within the external and internal domains have been heavily studied in isolation, how attention crosses between these domains remains uncharted territory. Here, we provide the first study to investigate brain dynamics associated with shifting attention between contents in the sensory environment and memory representations. Using a novel experimental design, we isolated the patterns and dynamics of brain activity associated with shifting attention within vs. between the external and internal domains. Our findings reveal early, dynamic, and distributed patterns of activity that distinguish within- from between-domain shifts, offering fascinating initial insights, and opening new questions for investigation.

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bioRxiv2023

Neural signatures of competition between voluntary and involuntary influences over the focus of attention in visual working memory

Adaptive behaviour relies on the selection and prioritisation of relevant sensory inputs from the external environment as well as from among internal sensory representations held in working memory. Recent behavioural evidence suggests that the classic distinction between voluntary (goal-driven) and involuntary (stimulus-driven) influences over attentional allocation also applies to the selection of internal representations held in working memory. In the current EEG study, we set out to investigate the neural dynamics associated with the competition between voluntary and involuntary control over the focus of attention in visual working memory. We show that when voluntary and involuntary factors compete for the internal focus of attention, prioritisation of the appropriate item is delayed - as reflected both in delayed gaze biases that track internal selection and in delayed neural beta (15-25 Hz) dynamics that track the planning for the upcoming memory-guided manual action. We further show how this competition is paralleled - possibly resolved - by an increase in frontal midline theta (4-8 Hz) activity that, moreover, predicts the speed of ensuing memory-guided behaviour. Finally, because theta increased following retrocues that effectively reduced working-memory load, our data unveil how frontal theta activity during internal attentional focusing tracks demands on cognitive control over and above working-memory load. Together, these data yield new insight into the neural dynamics that govern the focus of attention in visual working memory, and disentangles the contributions of frontal midline theta activity to the processes of control versus retention in working memory.

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bioRxiv2023

Attention and microsaccades: do attention shifts trigger new microsaccades or only bias ongoing microsaccades?

Brain circuitry that controls where we look also contributes to attentional focusing of visual contents outside of current fixation or contents held within the spatial layout of working memory. A behavioural manifestation of the contribution of oculomotor brain circuitry to selective attention comes from modulations in microsaccade direction that accompany attention shifts. Here, we address whether such modulations come about because attention itself triggers new microsaccades or whether, instead, shifts in attention only bias the direction of ongoing microsaccades - i.e., naturally occurring microsaccades that would have been made whether or not attention was also shifted. We utilised an internal-selective-attention task that has recently been shown to yield clear spatial microsaccade modulations and compared microsaccade rates following colour retrocues that were matched for sensory input, but differed in whether they invited an attention shift or not. If shifts in attention trigger new microsaccades then we would expect more microsaccades following attention-directing cues than following neutral cues. In contrast, we found no evidence for an increase in overall microsaccade rate following attention-directing cues, despite observing robust modulations in microsaccade direction. This implies that shifting attention biases the direction of ongoing microsaccades without changing the probability that a microsaccade will occur. These findings provide relevant context for complementary and future work delineating the links between attention, microsaccades, and upstream oculomotor brain circuitry, such as by helping to explain why microsaccades and attention shifts are often correlated but not obligatorily linked.

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