Biology subjects

Aboitiz, F.

Publications and source records attributed to Aboitiz, F..

4 recordsLinked to original sources

bioRxiv2026

Global Neural Oscillations Underlie Performance Variability and Attentional State Fluctuations in Humans

Fluctuations in attentional states, such as mind-wandering (MW), are associated with critical variability in task performance. While fMRI studies highlight the opposing roles of task-positive (e.g., dorsal attention network) and task-negative (e.g., default mode network) systems, the electrophysiological mechanisms underlying these dynamics remain poorly understood. Using intracranial electrocorticography in humans performing a sustained attention task, we identified global oscillatory dynamics linked to attentional shifts. MW was characterized by (i) reduced theta ({theta}) and alpha ({square}) power, (ii) decreased aperiodic signal components, indicating a shift toward cortical inhibition, (iii) enhanced phase synchronization across networks, and (iv) strengthened {theta} phase-behavior correlations ({rho}). These features support a non-network-specific framework in which low-frequency {theta} dynamics--captured by both {theta} power and {rho}--are associated with attentional fluctuations, while aperiodic offset relates to attentional state indirectly through its association with {rho} (Structural Equation Modeling: power[->]state {beta} = -0.118, p = 0.002; {rho}[->]state {beta} = 0.246, p < 0.001; offset[->]{rho} {beta} = -0.222, p < 0.001). Our study provides a unified neurophysiological framework for understanding how spontaneous neural activity can drive attentional fluctuations and performance variability, with implications for research on attention, learning, and neuropsychiatric disorders.

neuroscience↗

bioRxiv2020

Pupil-linked arousal is sensitive to subconscious processing of auditory novelty

Detection of novel stimuli that violate statistical regularities in the sensory scene is of paramount importance for the survival of biological organisms. Event-related potentials, phasic increases in pupil size, and evoked changes in oscillatory power in the theta (4-8 Hz) frequency range have been proposed as markers of sensory novelty detection. However, how conscious access to novelty modulates these different brain responses is not well understood. Here, we studied the neural responses to sensory novelty in the auditory modality with and without conscious access. We identified individual thresholds for conscious auditory discrimination and presented to our participants sequences of tones, where the last stimulus could be another standard, a subthreshold target or a suprathreshold target. Participants were instructed to report whether the last tone of each sequence was the same or different from those preceding it. Results indicate that stimulus evaluation and overt decision-making mechanisms, indexed by the P3 event-related response and reaction times, best predict whether a novel stimulus will be consciously accessed or not. In contrast, increased pupil size does not predict conscious access to novelty but reflects unexpected sensory uncertainty. These results highlight the interplay between bottom-up and top-down mechanisms and how the brain weights neural responses to novelty and uncertainty during perception and goal-directed behavior.

neuroscience↗

bioRxiv2020

Agency improves working memory and accelerates visual and attentional processing

Agency, understood as the ability of an organism to control stimuli onset, modulates perceptual and attentional functions. Since stimulus encoding is an essential component of working memory (WM), we conjectured that the perceptual processs agency would positively modulate WM. To corroborate this proposition, we tested twenty-five healthy subjects in a modified-Sternberg WM task under three stimuli presentation conditions: an unpredictable presentation of encoding stimulus, self-initiated presentation of the stimulus, and self-initiation presentation with random-delay stimulus onset. Concurrently, we recorded the subjects electroencephalographic signals during WM encoding. We found that the self-initiation condition was associated with better WM accuracy, and earlier latencies of N100 and P200 evoked potential components representing visual and attentional processes, respectively. Our work demonstrates that agency enhances WM performance and accelerates early visual and attentional processes deployed during WM encoding. We also found that self-initiation presentation correlates with an increased attentional state compared to the other two conditions, suggesting a role for temporal stimuli predictability. Our study remarks on the relevance of agency in sensory and attentional processing for WM.

neuroscience↗

bioRxiv2019

Loss of interplay: Frontoparietal dynamics underlie working memory deficits in multiple sclerosis

Working Memory (WM) impairment is the most common cognitive deficit of Multiple Sclerosis (MS) patients. However, evidence of its neurobiological mechanisms is scarce. Here we recorded electroencephalographic activity of twenty patients with relapsing-remitting MS and minimal cognitive deficit, and 20 healthy control (HC) subjects while they solved a WM task. In spite of similar performance, the HC group demonstrated both a correlation between temporoparietal theta activity and memory load, and a correlation between medial frontal theta activity and successful memory performances. MS patients did not show theses correlations leading significant differences between groups. Moreover, cortical connectivity analyses using granger causality and phase-amplitude coupling between theta and gamma revealed that HC group, but not MS group, presented a load-modulated progression of the frontal-to-parietal connectivity. This connectivity correlated with working memory capacity in MS groups. This early alterations in the oscillatory dynamics underlaying working memory could be useful for plan therapeutic interventions

neuroscience↗