Biology subjects

Ciria, L. F.

Publications and source records attributed to Ciria, L. F..

10 recordsLinked to original sources

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.

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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.

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bioRxiv2024

Proactive selective attention across competition contexts

Selective attention is a cognitive function that helps filter out unwanted information. Theories such as the biased competition model (Desimone & Duncan, 1995) explain how attentional templates bias processing towards targets in contexts where multiple stimuli compete for resources. However, it is unclear how the anticipation of different levels of competition influences the nature of attentional templates, in a proactive fashion. In this study, we used EEG to investigate how the anticipated demands of attentional selection (either high or low stimuli competition contexts) modulate target-specific preparatory brain activity and its relationship with task performance. To do so, participants performed a sex judgement task in a cue-target paradigm where, depending on the block, target and distractor stimuli appeared simultaneously (high competition) or sequentially (low competition). Multivariate Pattern Analysis (MVPA) showed that, in both competition contexts, there was a preactivation of the target category to select with a ramping-up profile at the end of the preparatory interval. However, cross-classification showed no generalization across competition conditions, suggesting different preparatory formats. Notably, time-frequency analyses showed differences between anticipated competition demands, reflecting higher theta band power for high than low competition, which mediated the impact of subsequent stimuli competition on behavioral performance. Overall, our results show that, whereas preactivation of the internal templates associated with the category to select are engaged in advance in both competition contexts, their underlying neural patterns differ. In addition, these codes could not be associated with theta power, suggesting different preparatory processes. The implications of these findings are crucial to increase our understanding of the nature of top-down processes across different contexts.

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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.

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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.

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bioRxiv2022

A call to rethink the cognitive benefits of physical exercise: An umbrella review of randomized controlled trials

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here, we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias, and large variation in combinations of preprocessing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% CI [0.16, 0.28]) that became substantially smaller after accounting for key moderators (i.e., active control and baseline differences; d = 0.13, 95% CI [0.07, 0.20), and negligible after correcting for publication bias (d = 0.05, 95% CrI [-0.09, 0.14]). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

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bioRxiv2021

Different underlying mechanisms for high and low arousal in probabilistic learning in humans

Humans are uniquely capable of adapting to highly changing environments by updating relevant information and adjusting ongoing behaviour accordingly. Here we show how this ability --termed cognitive flexibility-- is differentially modulated by high and low arousal fluctuations. We implemented a probabilistic reversal learning paradigm in healthy participants as they transitioned towards sleep or physical extenuation. The results revealed, in line with our pre-registered hypotheses, that low arousal leads to diminished behavioural performance through increased decision volatility, while performance decline under high arousal was attributed to increased perseverative behaviour. These findings provide evidence for distinct patterns of maladaptive decision-making on each side of the arousal inverted u-shaped curve, differentially affecting participants ability to generate stable evidence-based strategies, and introduces wake-sleep and physical exercise transitions as complementary experimental models for investigating neural and cognitive dynamics.

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bioRxiv2018

tDCS over the left prefrontal cortex does not affect time-trial self-paced cycling performance: Evidence from oscillatory brain activity and power output.

ObjectivesTo test the hypothesis that transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) influences performance in a 20-min time-trial self-paced exercise and electroencephalographic (EEG) oscillatory brain activity in a group of trained male cyclists.\n\nDesignThe study consisted of a pre-registered (https://osf.io/rf95j/), randomised, sham-controlled, single-blind, within-subject design experiment.\n\nMethods36 trained male cyclists, age 27 (6.8) years, weight 70.1 (9.5) Kg; VO2max: 54 (6.13) ml.min-1.kg-1, Maximal Power output: 4.77 (0.6) W/kg completed a 20-min time-trial self-paced exercise in three separate sessions, corresponding to three stimulation conditions: anodal, cathodal and sham. tDCS was administered before each test during 20-min at a current intensity of 2.0 mA. The anode electrode was placed over the DLPFC and the cathode in the contralateral shoulder. In each session, power output, heart rate, sRPE and EEG (at baseline and during exercise) was measured.\n\nResultsThere were no differences (F = 0.31, p > 0.05) in power output between the stimulation conditions: anodal (235 W [95%CI 222 - 249 W]; cathodal (235 W [95%CI 222 - 248 W] and sham (234 W [95%CI 220 - 248 W]. Neither heart rate, sRPE nor EEG activity were affected by tDCS (all Ps > 0.05).\n\nConclusiontDCS over the left DLFC did not affect self-paced exercise performance in trained cyclists. Moreover, tDCS did not elicit any change on oscillatory brain activity either at baseline or during exercise. Our data suggest that the effects of tDCS on endurance performance should be taken with caution.

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bioRxiv2017

Tonic and transient oscillatory brain activity during acute exercise

The physiological changes that occur in the main body systems and organs during physical exercise are well described in the literature. Despite the key role of brain in processing afferent and efferent information from organ systems to coordinate and optimize their functioning, little is known about how the brain works during exercise. The present study investigated tonic and transient oscillatory brain activity during a single bout of aerobic exercise. Twenty young males (19-32 years old) were recruited for two experimental sessions on separate days. Electroencephalographic (EEG) activity was recorded during a session of cycling at 80% (moderate-to-high intensity) of VO2max (maximum aerobic capacity) while performing an oddball task where participants had to detect infrequent targets presented among frequent non-targets. This was compared to a (baseline) light intensity session (30% VO2max). The light intensity session was included to control for any potential effect of dual-tasking (i.e., pedaling and performing the oddball task). A warm-up and cool down periods were completed before and after exercise, respectively. A cluster-based nonparametric permutations test showed an increase in power across the entire frequency spectrum during the moderate-to-high intensity exercise, with respect to light intensity. Further, we found that the more salient target lead to lower increase in (stimulus-evoked) theta power in the 80% VO2max with respect to the light intensity condition. On the contrary, higher decrease alpha and lower beta power was found for standard trials in the moderate-to-high exercise condition than in the light exercise condition. The present study unveils, for the first time, a complex brain activity pattern during acute exercise (at 80% of maximum aerobic capacity). These findings might help to elucidate the nature of changes that occur in the brain during physical exertion.

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bioRxiv2017

Neural Responses to Heartbeats of Physically Trained and Sedentary Young Adults

Regular physical exercise has a positive impact on brain function and cognitive performance. However, it is not yet clear whether the physiological and behavioral benefits associated to physical exercise are caused exclusively by changes in cardiovascular fitness. Here, we explore the relation between regular physical exercise and transient electroencephalographic responses to afferent cardiac signals. We find differences in the neural processing of heartbeats between individuals who exercise regularly and their sedentary counterparts. These differences, localised at two distinct spatio-temporal clusters, occur before the presentation of a target stimulus and correlate with behavioral performance only in the high-fit group. We hypothesise that the different neural processing of afferent cardiac activity by physically trained individuals reflects enhanced interoceptive sensitivity, which contributes to improved sustained attention. Our results are in line with recent research highlighting the role of neural monitoring of visceral signals in perceptual processing and even the generation of the sense of self.

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