Biology subjects

Feredoes, E.

Publications and source records attributed to Feredoes, E..

5 recordsLinked to original sources

bioRxiv2026

The behaviour bends, the code holds: working-memory category information in the multiple-demand network across graded interruption

Protecting working memory (WM) from interference is essential for goal-directed behaviour, yet its neural mechanisms remain unclear. The multiple-demand (MD) network - a set of frontoparietal regions recruited by diverse cognitive demands - is a candidate system for maintaining WM content under interference. We examined how the MD network represents a memorandum when an unrelated task interrupts maintenance. Participants memorised an image of a tool or animal and, during the delay, performed a digit task whose difficulty was parametrically varied (passive, easy, hard), allowing us to test how task engagement and associated cognitive demands affected concurrently maintained information. Using fMRI and multivariate pattern analysis, we decoded the maintained category (tool vs. animal) from 13 MD regions and early visual cortex. Behaviourally, interruption reduced recall accuracy, while the most demanding interrupter slowed responses. Neurally, category information was present during the delay, most strongly in visual cortex and bilateral intraparietal sulcus. This information was unaffected by task engagement (active vs. passive), consistently across decoding accuracy and cross-validated Mahalanobis (crossnobis) distance, with Bayesian evidence supporting the null effect. Increasing the demand of the active interrupter, however, produced a modest, network-wide reduction in crossnobis distance that was not detectable in decoding accuracy. Together, these findings reveal a dissociation between the behavioural costs of interruption and the neural representation of maintained category information. Although interruption impaired recall, engaging in an interrupter did not measurably alter category-level information in the MD network or visual cortex. Increasing the demand of the interrupter produced only a modest, network-wide reduction in representational distance, without affecting decoding accuracy, suggesting that the behavioural costs of interruption may not be fully explained by changes in the categorical representation of the memorandum.

neuroscience↗

bioRxiv2026

Dose-dependent ultrasound neuromodulation of the human brain

Transcranial ultrasound stimulation (TUS) can noninvasively modulate deep brain structures, but the relationship between delivered dose and neuromodulatory response remains poorly characterized in humans. Here, we show that ultrasound-induced tissue displacement measured in vivo predicts local and downstream functional neuromodulation. In 24 healthy adults, we combined magnetic resonance acoustic radiation force imaging (MR-ARFI) with concurrent TUS-fMRI in a double-blind, counterbalanced, within-subject design. Relative to active control stimulation, targeting the lateral geniculate nucleus (LGN) increased visually evoked BOLD responses in the LGN and ipsilateral primary visual cortex, localized to the retinotopic projection zone of the stimulated LGN site. Displacement predicted effect magnitude in both regions across participants and covaried with voxelwise responses within participants. Simulated in situ intensity showed no significant association with displacement or neuromodulatory response. These findings link in vivo mechanical displacement to functional modulation of a human thalamocortical circuit, providing an empirical basis for individualized dosing in causal neuroscience and clinical intervention.

neuroscience↗

bioRxiv2025

Cognitive modes involved in emotion regulation identified using Constrained Principal Component Analysis for fMRI (fMRI-CPCA)

Meta-analyses of functional magnetic resonance imaging (fMRI) studies have identified networks of widely distributed brain regions supporting emotion regulation. These overlap with attentional or cognitive control brain networks. The literature is short on data speaking to specific neurocognitive functions of these broad brain networks in reappraisal - a key emotion regulatory strategy involving the reframing of an event according to a goal to increase or decrease experienced emotion. We address this gap by examining both the spatial configuration and temporal profile of event-related blood oxygenation level dependent (BOLD) responses during a task requiring reappraisal. We analysed fMRI datasets obtained from 84 participants (51% female) who were instructed to increase or decrease their emotional response to unpleasant images. We extracted spatial maps and their estimated temporal event-related BOLD signal changes of four components with the highest loadings. Neurocognitive functions were derived by mapping each component onto templates of previously identified task-based cognitive modes. This analysis yielded four cognitive modes: 1) "multiple demand" 2) "response", 3) "re-evaluation", and 4) "default mode". The temporal profiles showed particularly prominent patterns for the increase and decrease conditions in "multiple demand" (mode 1) and "re-evaluation" (mode 3) respectively. These findings highlight a central role for specific neurocognitive processes linked to attentional control ("multiple demand") and switching ("re-evaluation"), as part of the broad brain networks supporting reappraisal. Moreover, the level of neural engagement of these cognitive modes varies depending on the regulatory goal. These findings provide tangible targets for neurocognitive interventions such as neurostimulation when emotion regulation is compromised.

neuroscience↗

bioRxiv2025

A plastic attractor model of flexible rule-based selective attention

A defining feature of human cognition is the ability to select and respond to stimuli flexibly in different circumstances. Here we show that a recently proposed class of small associative neural network, plastic attractors, can perform such flexible cognitive functions through the rapid formation of task-based attractors. We simulated a rule-based selective attention paradigm, in which agents respond to one task-relevant feature of a visual stimulus, while ignoring another, irrelevant feature, and respond to the attended feature according to a predefined stimulus-response mapping rule. The model consists of a broadly tuned prefrontal population with rapidly changing recurrent connections to sensory neurons that compete via lateral inhibition. In this framework, the rules governing the focus of selective attention are not coded explicitly, but arise as an emergent property of temporary associations between stimulus features and motor responses. The model exhibited activation properties that embody cornerstone concepts in current attentional theory including mixed selectivity, adaptive coding and biased competition, and reproduced a number of classic behavioral and neural findings. A causal test of the model using non-invasive brain stimulation concurrent with functional magnetic resonance imaging (TMS-fMRI) in humans showed that network perturbation reproduced neural decoding and behavioural data. When features were task-relevant, they rapidly formed synaptic connections with frontal cortex binding them into an attracting state, which manifest as prioritized representation of attended information, but this state was readily corrupted by brain stimulation. The model shows mechanistically that rapid synaptic changes could explain flexible rule-based control of attention.

animal behavior and cognition↗

bioRxiv2020

Concurrent neuroimaging and neurostimulation reveals a causal role for dlPFC in coding of task-relevant information

The way in which the brain prioritises processing of information relevant for our current goals is widely contested. Many studies implicate the dorsolateral prefrontal cortex (dlPFC), and propose that it drives brain-wide focus by biasing processing in favour of relevant information. An alternative, however, is that dlPFC is involved in the inhibition of irrelevant information. Here, we address this longstanding debate using the inferentially powerful approach of applying transcranial magnetic stimulation during functional magnetic resonance imaging (concurrent TMS-fMRI) and testing for changes in information coding using multivariate pattern analysis (MVPA). We ask whether dlPFC plays a causal role in prioritising information processing, and whether this is through selection of relevant information or inhibition of irrelevant information. Participants attended to one object feature whilst ignoring another feature of the same object. We reasoned that, if dlPFC is necessary for selection, active (disruptive) TMS should decrease coding of attended information compared to the low intensity (control) condition. Conversely, if right dlPFC is crucial for inhibition, active TMS should increase coding of irrelevant information relative to the control condition. The results showed that active TMS decreased coding of relevant information throughout the frontoparietal multiple demand regions, and that this impact was significantly stronger than the effect of TMS on irrelevant information coding, which was not statistically detectable. These data provide causal evidence for a specific role of dlPFC in supporting the representation of task-relevant information and demonstrate the crucial insights into high level cognitive-neural mechanisms possible with the combination of TMS-fMRI and MVPA.

neuroscience↗