Biology subjects

Alameda, C.

Publications and source records attributed to Alameda, C..

6 recordsLinked to original sources

bioRxiv2026

Neural dynamics track the approach to physical exhaustion

Physical exhaustion has long been described through its cardiorespiratory and metabolic cost, while the neural dynamics of its approach remain largely unexplored. Here we recorded high-density electroencephalography in 28 trained cyclists during a maximal incremental test to characterise how neural dynamics change towards exhaustion. As physiological strain rose, oscillatory power shifted to lower frequencies, neural activity became more regular and predictable, and functional coupling extended to longer timescales. Participant-specific models built on neural dynamics tracked proximity to exhaustion with accuracy comparable to cardiorespiratory measures. Over the final minutes, neural features remained informative while cardiorespiratory measures lost accuracy. Models trained across participants still tracked proximity to exhaustion, but less precisely. The approach to exhaustion thus follows a common neural path, tuned to each individual.

neuroscience↗

bioRxiv2026

Multisensory perceptual decision-making persists as alertness fades, even in the absence of an overt response

Momentary declines in alertness are common in everyday life, yet we must continue to make rapid and accurate decisions from multiple sensory signals that may converge or conflict. Here we investigated multisensory perceptual decision-making across the wake-sleep transition. Participants performed an audio-tactile spatial localisation task while electroencephalography tracked spontaneous fluctuations in alertness. Although drowsiness slowed responses and increased omissions, participants remained largely accurate, and the behavioural influence of congruent and conflicting tactile information persisted. Behavioural modelling revealed slower evidence accumulation and increased decision boundaries. Stimulus- and response-related neural patterns remained robustly decodable across alertness states, despite changes in their temporal dynamics but multisensory congruency was no longer reliably decoded during drowsiness. Brain signatures of lateralized motor preparation persisted during behavioural omissions and, under multisensory conflict, might even favour the competing response. Declining alertness does not uniformly degrade multisensory perceptual decision-making but selectively alters the processes linking sensory information to action.

neuroscience↗

bioRxiv2026

When the heart and the brain meet: Cardiac-neural coupling in feature integration

In contemporary Cognitive Neuroscience, increasing attention is devoted to brain-body interactions, as an expanding body of literature suggests that processing the external world may not emerge from the brain in isolation but rather from the coordinated contribution of multiple bodily systems. These interactions have been extensively studied in the context of interoception. However, evidence linking them to visual perception remains scarce. To address this gap, the present study examines heart-brain interactions during a visual feature integration task. The task of the participants required shape and color integration of features to identify a target while inhibiting distractor-related information. Cardiac and neural activity were simultaneously recorded, enabling the assessment of the heart rate (HR), heart-evoked potentials (HEP), and, albeit seldom reported previously, heart-evoked oscillations (HEO). Pre-stimulus cardiac-related neural activity differed between correctly and incorrectly integrated features. HEO analysis revealed alpha and low beta band modulations before target onset, which vanished when cardiac time-locking was removed, indicating that they were specifically driven by brain-heart coupling rather than by ongoing brain activity alone. These findings provide the first evidence that HEO dynamics contribute to successful perceptual integration and extend previous work on HEPs from stimulus detection to higher-level perceptual processes. More broadly, they suggest that cardiac signals shape early brain states that bias perception, supporting theoretical frameworks proposing an active role for bodily signals in perceptual processing. HighlightsO_LIPre-stimulus heart-evoked potentials differ between correct and incorrect feature integration. C_LIO_LIHeartbeat-locked alpha and low beta activity increase before correct feature integration C_LIO_LIPre-stimulus oscillatory effects vanish without cardiac activity, revealing HEO contribution. C_LIO_LIBrain-heart coupling biases perceptual outcomes. C_LI

neuroscience↗

bioRxiv2026

Drowsiness alters the neural dynamics but not the core computations of multisensory integration

Fluctuations in alertness shape perception and behaviour, yet how they affect the brains ability to integrate information across senses remains poorly understood. Here we investigated whether multisensory integration is preserved as humans transition from wakefulness to sleep. Participants (18 females, 8 males) performed an audio-tactile detection task while electroencephalography tracked spontaneous declines in alertness. Behaviourally, multisensory stimulation continued to facilitate responses during drowsiness, despite slowing and increased omissions. Although race-model predictions were consistent with preserved evidence for multisensory integration, event-related signatures of multisensory interactions were attenuated or no longer detectable during drowsiness. Crucially, multivariate decoding showed that multisensory neural representations remained detectable, although less temporally stable, and early cross-state generalization revealed shared representational structure across alertness levels, indicating preserved core multisensory computations. These findings show that multisensory integration remains functional but dynamically altered as alertness declines, revealing how the brain maintains adaptive behaviour during the wake-to-sleep transition. Significance StatementMultisensory integration has often been described as a stable and automatic perceptual process. However, growing evidence indicates that it can be modulated by ongoing brain states and cognitive demands. Here, we ask whether this computation remains invariant as alertness declines. We show that multisensory integration is neither abolished nor fully invariant during drowsiness. Instead, behavioural benefits are maintained despite less stable neural dynamics. Although event-related responses are attenuated, core multisensory representations remain shared across levels of alertness. These findings indicate that multisensory integration is preserved across fluctuations in alertness, while their neural dynamics are flexibly altered as alertness decreases.

neuroscience↗

bioRxiv2023

High arousal disrupts the neural signatures of conflict processing but not behavioural performance

Physical activation fluctuates throughout the day. Previous studies have shown that during periods of reduced activation, cognitive control remains resilient due to neural compensatory mechanisms. In this study, we in-vestigated the effects of high physical activation on both behavioural and neural markers of cognitive control. We hypothesized that while behavioural measures of cognitive control would remain intact during periods of high activation, there would be observable changes in neural correlates. In our electroencephalography study, we manipulated levels of physical activation through physical exercise. Although we observed no significant impact on behavioural measures of cognitive conflict, both univariate and multivariate time-frequency markers proved unreliable under conditions of high activation. Moreover, there was no modulation of whole-brain connectivity measures by physical activation. We suggest that this dissociation between behavioural and neural measures indicates that the human cognitive control system remains resilient even at high activation, possibly due to underlying neural compensatory mechanisms.

neuroscience↗

bioRxiv2023

Staying in control: characterising the mechanisms underlying cognitive control in high and low arousal states

Throughout the day, humans show natural fluctuations in arousal that impact cognitive function. To study the behavioural dynamics of cognitive control during high and low arousal states, healthy participants performed an auditory conflict task during high-intensity physical exercise (N = 39) or drowsiness (N = 33). In line with the pre-registered hypotheses, conflict and conflict adaptation effects were preserved during both altered arousal states. Overall task performance was markedly poorer during low arousal, but not for high arousal. Modelling behavioural dynamics with drift-diffusion analysis revealed evidence accumulation and non-decision time decelerated, and decisional boundaries became wider during low arousal, whereas high arousal was unexpectedly associated with a decrease in the interference of task-irrelevant information processing. These findings show how arousal differentially modulates cognitive control at both sides of normal alertness, and further validates drowsiness and physical exercise as key experimental models to disentangle the interaction between physiological fluctuations on cognitive dynamics.

neuroscience↗