Biology subjects

Jensen, O.

Publications and source records attributed to Jensen, O..

At least 19 recordsLinked to original sources

bioRxiv2026

Older Adults Show Preserved Neural Signatures of Audiovisual Integration but Altered Links to Speech Comprehension

Older adults often experience difficulty understanding speech in noisy environments despite relatively preserved hearing. Although visual speech cues can improve speech perception, it remains unclear whether the neural mechanisms supporting audiovisual integration are preserved in healthy ageing. We addressed this question using magnetoencephalography (MEG) combined with Rapid Invisible Frequency Tagging (RIFT) during challenging audiovisual speech task. Forty younger and forty older adults attended to one of two competing speech streams while the speaker's lip movements were frequency tagged, with the visual modulation driven by either the attended or unattended speech envelope. Task-Relevant amplitude modulation of frequency tagging in visual speech improved speech comprehension in younger adults as previously reported for this cohort; this accuracy benefit was absent in older adults. Auditory and visual tagging responses were modulated by task relevance similarly across age groups, indicating largely preserved modality-specific sensory processing in older adults. Intermodulation responses, reflecting nonlinear interactions between auditory and visual speech signals, also remained sensitive to task relevance and did not differ in their condition-dependent modulation between age groups. Greater Task-Relevant versus Task-Irrelevant differences in intermodulation coherence were also associated with greater comprehension benefits in younger adults; no significant association was found in older adults, and this relationship differed significantly between age groups. These findings suggest that the absence of a comprehension benefit in older adults is linked to a change in the relationship between audiovisual intermodulation and behaviour, despite largely preserved task-sensitive brain responses.

neuroscience↗

bioRxiv2026

Cortico-cerebellar beta-band dynamics predict flexible motor timing

Flexible motor control requires that movements adapt to changing temporal contexts. Here, we test whether flexible timing is driven by context-dependent encoding across cortico-cerebellar circuits and how neural dynamics within these circuits enable accurate performance. To overcome the signal-to-noise limitations of conventional electro- and magnetoencephalography, we recorded whole-head neural dynamics using optically pumped magnetometer arrays (OPM-MEG). Participants learned a context-dependent task, executing manual button presses at time intervals 800 ms (T1) and 1,600 ms (T2), respectively, to avoid a periocular air puff, which was associated with an implicit conditioned eyeblink. We found that the motor cortex contralateral to the hand and bilateral cerebellar lobule VI dynamically encoded these intervals through beta-band (13-30 Hz) event-related desynchronisation (ERD) that precisely scaled with T1 and T2. The cerebellar trial-by-trial latency of the beta-band ERD predicted the timing of explicit manual actions. Finally, partial directed coherence revealed that baseline bidirectional beta-band coupling across the network transiently weakened from the ipsilateral cerebellum to the contralateral motor cortex during finger movement execution. Our findings show that cortico-cerebellar coupling functions as a gating mechanism and suggest that cerebellar circuits modulate cortical motor activity for flexible, accurate motor timing.

neuroscience↗

bioRxiv2026

Non-invasive tracking of ripple-like activity during human sleep using MEG

Hippocampal ripples are considered a key mechanism of sleep-dependent memory consolidation. In humans, however, their direct investigation has relied on invasive recordings from patients with epilepsy, because EEG provides limited access to fast activity from deep medial temporal structures. Here, we tested whether source-resolved magnetoencephalography can reveal physiologically meaningful ripple-like activity during NREM sleep in healthy humans. These events showed hallmarks expected of sleep ripples: they were most prominent in medial temporal regions and embedded within slow oscillation (SO)-spindle dynamics, occurring preferentially during SO up-states and spindle centers. To test mnemonic relevance, we combined sleep MEG with targeted memory reactivation, in which learning cues were replayed during sleep. TMR improved memory performance, and later remembered cues preferentially recruited medial temporal ripple-like events alongside cortical spindles. Ripple-like events also coincided with enhanced item-specific reactivation during successful TMR. Together, these findings establish MEG as a non-invasive window onto hippocampo-cortical memory dynamics during sleep.

neuroscience↗

bioRxiv2026

Laterality of subcortical structures predicts spontaneous brain dynamics

Subcortical structures play a key role in shaping cortical computation through distributed cortico-subcortical networks, yet it remains unclear whether individual differences in subcortical anatomy are reflected in resting-state cortical oscillations. We analysed resting-state magnetoencephalography (MEG) and structural MRI from 533 healthy adults in the Cambridge Centre for Ageing and Neuroscience (CamCAN) cohort to test whether hemispheric asymmetries in subcortical volume predict asymmetries in cortical oscillatory power. Lateralisation indices were calculated for subcortical volumes and for oscillatory power across homologous MEG sensor pairs. Cluster-based permutation testing revealed frequency-specific associations between subcortical anatomy and cortical activity. Globus pallidus asymmetry was positively associated with posterior alpha-band power lateralisation, putamen and caudate asymmetries were associated with beta-band lateralisation, and hippocampal asymmetry was negatively associated with delta-band lateralisation. These findings extend previous task-based observations linking pallidal anatomy with alpha oscillations to the resting state and demonstrate that distinct subcortical structures are associated with specific cortical frequency bands. Our results suggest that resting-state MEG captures functional signatures of cortico-subcortical organisation and provides a non-invasive framework for studying healthy ageing and disorders involving subcortical degeneration.

neuroscience↗

bioRxiv2026

Augmenting Speech Comprehension using Rapid Frequency Tagging

Speech comprehension under adverse listening conditions benefits from visual speech, but whether visual input can be modulated to improve listening remains unclear. Here we used rapid frequency tagging, a non-invasive sensory stimulation technique, in which the visual tag at 55 Hz over the mouth region of a talking face was amplitude-modulated by the envelope of either the task-relevant or task-irrelevant speech stream. When the visual modulation followed the task-relevant speech envelope, comprehension improved relative to task-irrelevant modulation and to an unmodulated tagging control. MEG responses showed enhanced 55 Hz visual tagging, altered 40 Hz auditory tagging and a non-linear 15 Hz intermodulation. Individual comprehension gains were associated with intermodulation responses in left inferior frontal cortex, linking behavioural benefit to audiovisual interaction. These findings show that task-relevant visual stimulation can improve comprehension by strengthening audiovisual interaction, establishing amplitude-modulated frequency tagging as a tool for probing and supporting comprehension in challenging environments.

neuroscience↗

bioRxiv2026

A Candida glabrata adhesin-like effector drives fitness and immunogenicity in the gut

Candida glabrata is a leading cause of invasive candidiasis. The gut serves as its primary reservoir, yet factors governing colonization and pathogenic potential remain poorly defined. Here, we identify immunoglobulin A (IgA) as a key regulator of C. glabrata within the intestinal microbiome. We found that C. glabrata induces an IgA response in a strain-specific manner. Comparative transcriptional and proteomic analyses of IgA-inducing and non-inducing strains identified a putative adhesin, Awp11, whose expression correlated with IgA induction. Awp11 is directly targeted by IgA and is required for inducing C. glabrata-specific IgA and Th17 responses in vivo. Functionally, Awp11 promotes colonization of a complex intestinal microbiome, and intestinal IgA limits this advantage. In most strains, AWP11 transcription is dynamic and limited by IgA in the gut. This identifies Awp11 as a key determinant of strain-dependent immunogenicity and gut colonization that C. glabrata may dynamically regulate to balance colonization and immune evasion.

immunology↗

bioRxiv2026

Transformed reactivation of latent working memory enables hierarchical language processing

Human language comprehension requires tracking words across intervening material to construct grammatical structures, yet two fundamental questions remain unresolved: whether maintenance of earlier words relies on sustained neural activity or activity-silent working memory mechanisms, and whether memory retrieval during integration engages domain-general or language-selective networks. Using magnetoencephalography with time-resolved decoding, we tracked main-clause subjects as participants heard sentences with embedded clauses (e.g., "The dog, who chases the cat, jumps over the mud."). The subject representation ("dog") decayed to baseline during the embedded clause but reactivated after the main-clause verb ("jumps"), with transformed rather than reinstated neural codes. Critically, reactivation emerged first in right dorsolateral prefrontal cortex before engaging frontotemporal language regions, and reactivation strength was modulated by syntactic structure and predicted comprehension accuracy. These findings demonstrate activity-silent working memory maintenance, structure-dependent retrieval, and cooperative function of domain-general and language-selective networks during hierarchical language processing.

neuroscience↗

bioRxiv2026

OPM-FLUX: A Pipeline for OPM MEG Data Analysis

Optically pumped magnetometer-based magnetoencephalography (OPM-MEG) has recently emerged as a powerful neuroimaging approach in cognitive neuroscience, extending beyond the limitations of conventional cryogenic systems with greater experimental flexibility and wearable recording. Despite these advantages, standardised data analysis frameworks specifically tailored to OPM technology are still lacking, leading to variability in processing choices and reduced reproducibility across laboratories and hardware platforms. We introduce OPM-FLUX, a comprehensive and fully documented end-to-end analysis pipeline developed for OPM-MEG data. The pipeline defines a clear sequence of preprocessing, noise suppression, artifact handling, spectral analysis, evoked response analysis along with recommended parameter settings. It also includes source reconstruction to identify where in the brain the signals originate. In addition, OPM-FLUX supports multivariate pattern analysis (MVPA), enabling time-resolved decoding of cognitive processes from sensor level data. OPM-FLUX is implemented in MNE-Python and distributed as interactive Jupyter Notebooks that combine executable code with detailed methodological explanations and graphical outputs. The pipeline further provides standardized reporting templates and a data acquisition Standard Operating Procedure to facilitate preregistration, consistent documentation, and standard practices across research sites. The workflow is demonstrated using openly available datasets acquired from both Cerca/QuSpin and FieldLine OPM systems during a visuospatial attention paradigm that modulates alpha, beta, and gamma oscillations and elicits event-related responses. By supporting multiple OPM platforms and promoting consistent methodological choices, OPM-FLUX enhances transparency, comparability, and replication in OPM-MEG research. The pipeline also serves as an educational resource for students and researchers entering the field and is designed to evolve alongside ongoing technological and methodological advances in OPM-based brain imaging.

neuroscience↗

bioRxiv2025

Rhythmic light stimulation elicits multiple concurrent neural responses that separably shape human perception

Rhythmic light stimulation offers solutions to innumerable cognitive and neurological disorders. However, like any neuromodulatory technique, responses to rhythmic light stimulation are highly variable, producing challenges in replicating lab-based studies and translating findings to the clinic. Across three MEG/EEG experiments, we show that this variability can, in part, be attributed to rhythmic light stimulation eliciting multiple, coexisting neural responses which have separable impacts on cognition. Specifically, we find that rhythmic light stimulation produces distinct neural responses at the fundamental (f) and second harmonic (2f) frequencies, and that these responses are differentially shaped by endogenous oscillatory dynamics that vary across participants. Importantly, these responses separably contribute to perception, with harmonic gamma-band responses supporting the representation of stimulus-specific information, and the phase of harmonic alpha-band responses causally contributing to near-threshold visual perception. We reproduce these effects across datasets, paradigms, and oscillatory bands, suggesting that the multiplex oscillatory responses elicited by rhythmic light stimulation are a robust and pervasive phenomenon. We propose that the complexity of neural responses to rhythmic stimulation can explain why there is substantial variability between studies using these techniques, and that understanding these complex responses may help advance neuromodulatory technologies for both fundamental and clinical neuroscience. Supplementary MaterialAll supplementary material can be found at the end of this document.

neuroscience↗

bioRxiv2025

Decoding with multivariate pattern analysis is superior for optically pumped magnetometer-based magnetoencephalography compared to superconducting quantum interference device-based systems

BackgroundMultivariate pattern analysis (MVPA) has become an increasingly important method for decoding distributed brain activity from neural electrophysiological recordings by leveraging both temporal and spatial features. These multivariate approaches have proven important for both cognitive neuroscience and brain-computer interfaces. MVPA might benefit from magnetoencephalography (MEG) systems based on optically pumped magnetometers (OPMs), as these sensors can be placed closer to the scalp, providing higher spatial resolution compared to conventional MEG systems that rely on superconducting quantum interference devices (SQUIDs). As OPM-based MEG systems become available at more institutions, it is essential to experimentally compare their performance with traditional SQUID-based systems using MVPA. MethodsWe adapted a visual object-word paradigm from a previous study, originally implemented on a TRIUX MEGIN SQUID system, to the FieldLine HEDscan OPM system. Participants were recruited and we recorded their ingoing brain activity while did the same task in both systems. Visual stimuli of different objects were presented alternately in two modalities: pictures and the corresponding written words. For each modality, MVPA was used to classify the objects from OPM and SQUID magnetometers data respectively. To further investigate the advantages of OPM, we evaluated the effect classification accuracy of two spatial factors by controlling the number of sensors included and the spatial frequency content of the sensor data. ResultsWe found higher time-resolved decoding accuracy for the OPM compared to the SQUID data. Moreover, OPMs show higher classification performance compared to SQUIDs when controlling for the same number of sensors; consistently, the OPM system required fewer sensors to reach the performance limit of the SQUID system. Our analysis considering the spatial frequency content of the signal revealed that decoding accuracy plateaued for the SQUID system at lower spatial frequencies while the performance of the OPM system continued to improve when higher-order spatial components were included. ConclusionOur OPM-MEG system outperformed the SQUID-MEG system on MVPA on decoding of visual processing. This advantage of OPM is driven by its higher spatial resolution, resulting from the sensors being positioned closer to the head and thus able to capture higher spatial frequency components of the brain signal. OPM may facilitate cognitive neuroscience research as well as brain-computer interfaces by providing higher sensitivity when employing paradigms using multi-variate data analysis.

neuroscience↗

bioRxiv2025

Hemispheric laterality of the putamen predicts pseudoneglect

Healthy individuals tend to exhibit a subtle leftward attentional bias, a phenomenon termed pseudoneglect. While this bias is thought to reflect a right-hemisphere dominance when allocating spatial attention, the contribution of subcortical structures remains poorly understood. Although lesion and neuroimaging studies in clinical populations have implicated asymmetries in the basal ganglia and thalamus to dysfunction in spatial attention, it remains unclear whether naturally occurring subcortical asymmetries in healthy individuals predict behavioural biases in spatial attention. In this study, we investigated whether volumetric asymmetries in subcortical structures are associated with biases in spatial attention in a non-clinical population. This was achieved by using the landmark task to assess spatial biases, alongside acquiring T1-weighted MRI data from 44 healthy participants. The subcortical regions were segmented using the FIRST algorithm to estimate the volumetric asymmetry of specific regions. We found that variability in pseudoneglect was predicted by the degree of leftward lateralisation of putamen volume, indicating that the putamen contributes to the magnitude of spatial attention biases. This also suggests that the left putamen may support right-hemisphere neocortical dominance through the indirect pathway. These findings bridge anatomical and behavioural measures, highlighting the functional relevance of subcortical asymmetry in shaping attentional processes in the healthy brain. Our findings pave the way for early diagnosis of neurological disorders associated with subcortical atrophies including Parkinsons Disease and dementia. Significance StatementHemispheric dominance in cortical networks shape attentional biases, but the role of subcortical structures remains poorly understood. Here we show that natural variability in the lateralisation of the putamen predicts individual differences in pseudoneglect--a subtle leftward bias in spatial attention observed in healthy adults. Using MRI and psychophysics, we demonstrate that greater leftward putamen asymmetry is associated with stronger leftward bias, independent of eye dominance and microsaccadic behaviour, and moderated by handedness. These findings reveal a structural subcortical basis for attentional asymmetries and suggest that simple behavioural measures could serve as non-invasive markers of early subcortical changes relevant to disorders such as Parkinsons disease, Alzheimers disease, and ADHD.

neuroscience↗

bioRxiv2025

Infant Brains Tick at 4Hz - Resonance Properties of the Developing Visual System

Neural rhythms of the infant brain are not well understood. Testing the rhythmic properties of the adult visual system with periodic or broadband visual stimulation elicited neural resonance phenomena at [~]10Hz alpha rhythm. To investigate the rhythmic properties of the infant brain upon visual stimulation, eight-month-olds (N = 42) were presented with visual stimuli flickering at discrete frequencies (2, 4, 6, 8, 10, 15, 20, and 30Hz) and broadband (i.e., aperiodic) stimulation, while recording a high-density electroencephalogram (EEG). Infants visual system entrained to the harmonics of the periodic stimulation frequencies (first to third). Crucially, a 4Hz rhythm emerged independent of stimulation frequency and the impulse response function (IRF) of the broadband sequence revealed a perceptual echo, reverberating visual information at 4Hz. This echo lasted for about 1 second, extended into frontal sensors, and selectively resonated the 4Hz component of the input signal. In a complementary adult sample, we confirm an alpha response upon periodic and broadband stimulation. To conclude, perturbing the infant visual system elicited a neural response and resonant activity at the 4Hz theta rhythm, which contrasts with the 10Hz alpha rhythm found in the adult visual system. Neural processing dynamics are thus essential to understand early brain development in full. Significance StatementThis study tested resonance properties of the infant visual system upon perturbation. For the visual stimulation at discrete frequencies between 2 and 30Hz, the infant brain responded at 4Hz independent of the stimulation frequency. Following broadband stimulation, a perceptual echo at 4Hz emerged - resonating the 4Hz component of visual information over several cycles. These findings reveal that the 4Hz theta rhythm is an inherent processing dynamic of the infant visual system, contrasting with the 10Hz rhythm found in adults. The processing dynamics of the human visual system undergo fundamental changes from infancy into adulthood.

neuroscience↗

bioRxiv2025

Higher baseline alpha power is associated with faster responses in visual search

Visual search models have long emphasised that task-relevant items must be prioritized for optimal performance. While it is known that search efficiency also benefits from active distractor inhibition, the underlying neuronal mechanisms are debated. Neuronal alpha oscillations (7-14 Hz) have been associated with functional inhibition of cortical excitability, as well as distractor suppression in spatial attention and visual working memory tasks. We therefore hypothesised that alpha oscillations similarly support the deselection of distractors in visual search. Using Magnetoencephalography (MEG), we here show that high alpha power before the onset of a complex search display is associated with faster search performance. Crucially, we used a General Linear Model (GLM) approach to control for confounds between alpha power and task duration, ruling out that this result was merely driven by practice effects paired with increased fatigue over time. In addition to spontaneous oscillatory activity, we quantified the cortical excitability to colours of the search stimuli based on Rapid Invisible Frequency Tagging (RIFT) responses. In contrast to our initial hypothesis, increased pre-search alpha power did not correlate with the RIFT response, providing no direct evidence for feature-specific inhibition of distracting stimuli by alpha. Our findings challenge the traditional view of alpha oscillations reducing visual processing, showing instead that increased occipital alpha power can enhance performance in a visual task. We propose that the increase in alpha power may reflect increased top-down control supporting visual search

neuroscience↗

bioRxiv2025

Parallel and dynamic attention allocation during natural reading

During natural reading, attention constantly shifts across words, yet how linguistic properties (e.g., lexical frequency) impact the allocation of attention remains unclear. In this study, we co-registered MEG data and eye movements while participants read one-line sentences containing target words of either low or high lexical frequency. Using rapid invisible frequency tagging (RIFT), we simultaneously tracked attention to target and post-target words by flickering them at different frequencies. First, we provide neural evidence that attention was allocated simultaneously to both foveal target and parafoveal post-target words. Second, we found an early parafoveal lexical effect, whereby lower frequency targets demanded more attention prior to fixation, and, additionally, a foveal load effect whereby lower frequency targets reduced the amount of attention allocated to post-targets. Furthermore, flexibility in attention shifts between foveal and parafoveal processing correlated with individual reading speed. These results suggest attention is distributed across multiple words and is flexibly adjusted during reading.

neuroscience↗

bioRxiv2025

Neural Sharpening of Object Categories Through Parafoveal Priming

During natural vision, humans make saccades approximately every 250 - 300 ms to fixate on important objects in a scene. Given this rapid succession of eye movements, it has been proposed that visual processing begins in the parafovea, prior to fixation. Such parafoveal previewing may serve as a form of priming, facilitating subsequent processing at fixation. In this study, we investigated whether parafoveal priming leads to both a reduced neural response - akin to repetition suppression - and a more selective neural representation, consistent with neuronal sharpening. Participants performed a visual exploration task involving natural object images that were either parafoveally previewed or not, while magnetoencephalographic (MEG) data were recorded. Event-related fields revealed a reduced neural response when an image had been parafoveally presented 250 ms earlier. Moreover, multivariate pattern analysis showed enhanced decoding of object category following parafoveal priming, suggesting increased neural specificity. These findings support the idea that parafoveal previewing contributes to neural sharpening, potentially aiding evidence accumulation by forming sparse and precise representations of objects during visual scene exploration.

neuroscience↗

bioRxiv2025

Statistical learning drives anticipatory micro-saccades toward suppressed distractor locations

Statistical learning enables individuals to suppress locations associated with salient distractors, yet the mechanisms underlying this suppression remain unclear. Proactive accounts propose that suppression operates without prior attentional allocation to distractor locations, whereas reactive accounts suggest that suppression requires covert attention to the distractor location before it can be engaged. To address this ongoing debate, the current study recorded micro-saccades--an index of covert attention--during the pre-stimulus interval, alongside electroencephalogram (EEG) data collected during a visual search task. Participants were instructed to ignore a salient distractor that occurred more frequently at a specific location. Statistical learning reduced attentional capture for distractors presented at this high-probability location, and this effect was accompanied by oculomotor markers: micro-saccade rates decreased before stimulus onset relative to a control condition. Strikingly, these anticipatory micro-saccades were more often directed toward high-probability distractor locations than away from them, consistent with a reactive suppression mechanism. In parallel, alpha-band activity (8-14 Hz) carried decodable representations of high-probability distractor locations, indicating preparatory neural tuning. Overall, these findings provide evidence that the oculomotor system is closely involved in encoding and responding to learned spatial regularities.

neuroscience↗

bioRxiv2025

Predictive distractor processing relies on integrated proactive and reactive attentional mechanisms

Visual attention is shaped by statistical regularities in the environment, with spatially predictable distractors being proactively suppressed. The neural mechanisms underpinning this suppression remain poorly understood. In this study, we employed magnetoencephalography (MEG) and multivariate decoding analysis to investigate how predicted distractor locations are proactively processed in the human brain. Male and female human participants engaged in a statistical learning visual search task that required them to identify a target stimulus while ignoring a colour-singleton distractor. Critically, the distractor appeared more frequently on one side of the visual field, creating an implicit spatial prediction. Our results revealed that distractor locations were encoded in temporo-occipital brain regions prior to the presentation of the search array, supporting the hypothesis that proactive suppression guides visual attention away from predictable distractors. The neural activity patterns corresponding to this pre-search distractor processing extended to post-search activity during late attentional stages ([~]200 ms), suggesting an integrated suppressive mechanism. Notably, this generalization from pre- to post- search phases was absent in the early sensory processing stages ([~]100 ms), suggesting that post-search distractor processing is not merely a continuation of sustained proactive processing, but involves re-engagement of the same mechanism at distinct stages. These findings establish a mechanistic link between proactive and reactive processing of predictable distractors, demonstrating both shared and unique contributions to attentional selection.

neuroscience↗

bioRxiv2024

Guided Visual Search is associated with a feature-based priority map in early visual cortex

Visual search models have long emphasised that task-relevant items must be prioritised for optimal performance. While it is known that search efficiency also benefits from active distractor inhibition, the underlying neuronal mechanisms are debated. Here, we used MEG in combination with Rapid Invisible Frequency Tagging (RIFT) to probe how neuronal excitability in early visual cortex is modulated during feature-guided visual search. Participants were instructed to indicate the presence or absence of a letter "T" presented amongst 16 and 32 "L"s. In the guided search condition, participants were informed about the colour of the "T" and could infer the colour of the irrelevant distractors. In the unguided search condition, the target colour was unknown. We found that guided search was associated with enhanced RIFT responses to the target colour, and decreased responses to the distractor colour compared to unguided search. These results conceptually replicated using both a conventional coherence approach, as well as with a General Linear Model approach based on a single-trial measure of the RIFT response. The present findings expand on previous reports based on electrophysiology and fMRI in humans and non-human primates by revealing that feature-guidance in visual search affects neuronal excitability as early as primary visual cortex.

neuroscience↗