Biology subjects

van Harmelen, A. M.

Publications and source records attributed to van Harmelen, A. M..

3 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.

neuroscience↗

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.

neuroscience↗

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.

neuroscience↗