Biology subjects

Ruzzoli, M.

Publications and source records attributed to Ruzzoli, M..

6 recordsLinked to original sources

bioRxiv2023

Developmental changes in individual alpha frequency: Recording EEG data during public engagement events

Statistical power in cognitive neuroimaging experiments is often very low. Low sample size can reduce the likelihood of detecting real effects (false negatives) and increase the risk of detecting non-existing effects by chance (false positives). Here we document our experience of leveraging a relatively unexplored method of collecting a large sample size for simple electroencephalography (EEG) studies: by recording EEG in the community during public engagement and outreach events. We collected data from 346 participants (189 females, age range 6-76 years) over 6 days, totalling 29 hours, at local science festivals. Alpha activity (6-15 Hz) was filtered from 30 seconds of signal, recorded from a single electrode placed between the occipital midline (Oz) and inion (Iz) while participants rested with their eyes closed. A total of 289 good quality datasets were obtained. Using this community-based approach, we were able to replicate controlled, lab-based findings: IAF increased during childhood, reaching a peak frequency of 10.28 Hz at 28.1 years old, and slowed again in middle and older age. Total alpha power decreased linearly, but the aperiodic-adjusted alpha power did not change over the lifespan. Aperiodic slopes and intercepts were highest in the youngest participants. There were no associations between these EEG indexes and self-reported fatigue, measured by the Multidimensional Fatigue Inventory. Finally, we present a set of important considerations for researchers who wish to collect EEG data within public engagement and outreach environments.

neuroscience↗

bioRxiv2020

The phase of Theta oscillations modulates successful memory formation at encoding

Several past studies have shown that attention and perception can depend upon the phase of ongoing neural oscillations at stimulus onset. Here, we extend this idea to the memory domain. We tested the hypothesis that ongoing fluctuations in neural activity have an impact on memory encoding using a picture paired-associates task to gauge episodic memory performance. Experiment 1 capitalized on the principle of phase reset. We tested if subsequent memory performance fluctuates rhythmically, time-locked to a reset cue presented before the to-be-remembered pairs. We found indication that behavioral performance was periodically and selectively modulated at theta frequency ([~]4 Hz). In Experiment 2 we focused on prestimulus ongoing activity using scalp EEG recorded while participants performed the pair-associate task. We analyzed subsequent memory performance as a function of theta and alpha activity around the presentation of the to-be-remembered pairs. The results of the pre-registered analyses, using large electrode clusters and generic spectral ranges, returned null results of prestimulus phase-behavior correlation. However, we found that post-stimulus theta-power modulations in left frontal scalp predicted subsequent memory performance. This post-stimulus effect in theta power was used to guide a post-hoc prestimulus phase analysis, narrowed down to more precise scalp location and frequency. This analysis returned a correlation between prestimulus theta phase and subsequent memory. Altogether, these results suggest that the prestimulus theta activity at encoding has an impact on later memory performance.

neuroscience↗

bioRxiv2020

Can the occipital alpha-phase speed up visual detection through a real-time EEG-based brain-computer interface (BCI)?

Electrical brain oscillations reflect fluctuations in neural excitability. Fluctuations in the alpha band (, 8-12 Hz) in the occipito-parietal cortex are thought to regulate sensory responses, leading to cyclic variations in visual perception. Inspired by this theory, some past and recent studies have addressed the relationship between -phase from extra-cranial EEG and behavioural responses to visual stimuli in humans. The latest studies have used offline approaches to confirm -gated cyclic patterns. However, a particularly relevant implication is the possibility to use this principle online for real-time neurotechnology, whereby stimuli are time-locked to specific -phases leading to predictable outcomes in performance. Here we aimed at providing a proof-of-concept for such real-time neurotechnology. Participants performed a speeded response task to visual targets that were presented upon a real-time estimation of the -phase via an EEG closed-loop brain-computer interface (BCI). We predicted, according to the theory, a modulation of reaction times (RTs) along the -cycle. Our BCI system achieved reliable trial-to-trial phase-locking of stimuli to the phase of individual occipito-parietal -oscillations. Yet, the behavioural results did not support a consistent relation between RTs and the phase of the -cycle neither at group nor single participant levels. We must conclude that although the -phase might play a role in perceptual decisions from a theoretical perspective, its impact on EEG-based BCI application appears negligible.

neuroscience↗

bioRxiv2019

Neural evidence of cognitive conflict during binocular rivalry

To make sense of ambiguous and, at times, incomplete sensory input, the brain relies on a process of active interpretation. At any given moment, only one of several possible perceptual outcomes prevails in our conscious experience. Our hypothesis is that the competition between alternative representations induces cognitive conflict, eventually leading to fluctuations between different perceptual interpretations. We used binocular rivalry, a popular protocol to probe changes in perceptual awareness [1-3] and drew on the conflict monitoring theory, which holds that cognitive control is invoked by the detection of conflict during information processing. We looked for an increase in power of fronto-medial theta oscillations (5-7 Hz), an established EEG marker of conflict detection [4-7]. Our results show that fm-theta power increases right before perceptual alternations and decreases thereafter, suggesting that conflict monitoring is related to perceptual competition. Furthermore, to investigate conflict resolution via attentional engagement, as held by the conflict monitoring theory [8], we also looked for changes in parieto-occipital alpha oscillations (8-12 Hz) associated to perceptual switches. These oscillations have been associated to attention allocation via functional inhibition in sensory cortices [9-12]. The power of parieto-occipital alpha was inversely related to that of fm-theta, reflecting periods of high inter-ocular inhibition during stable perception, and low inhibition around moments of perceptual change. Our findings validate a prediction made 20 years ago in the seminal paper formulating the conflict monitoring theory, and establish a previously unknown link between conflict mechanisms and the processes leading to perceptual awareness. HighlightsO_LIBinocular rivalry induces conflict between competing perceptual representations C_LIO_LIMid-frontal theta power increases around the resolution of perceptual conflict C_LIO_LIPosterior alpha decreases reflect neural excitability around perceptual switches C_LIO_LIThe results link cognitive conflict theory with perceptual inference C_LI

neuroscience↗

bioRxiv2019

From cognitive control to creativity: The conflict resolution of surrealistic imagery

Surrealistic imagery juxtaposes common visual elements to create un-ordinary associations with semantically conflicting representations. We hypothesize that these images engage the conflict processing network that has been described in cognitive neuroscience theories, and probed with laboratory protocols such as the Stroop or Flanker tasks. We addressed this hypothesis by measuring mid-frontal Theta power using EEG while participants watched surrealistic images through a social media-like interface. Surrealistic images, compared to controls, produced a significant Theta power increase, as predicted from cognitive conflict theory. We also found increased memory for surrealistic images one week after exposure, compared to the controls. These findings provide evidence for the surrealistic artistic strategy to effectively engage viewer s cognitive control and boost memorability. In these studies, we provide validation of cognitive theories in real-life scenarios and insights regarding the use of neural correlates as effectiveness metrics in creative communication, as well as the arts.

neuroscience↗

bioRxiv2019

Integrating When and What Information in the Left Parietal Lobe Allows Language Rule Generalization

A crucial aspect when learning a language is discovering the rules that govern how words are combined in order to convey meanings. Since rules are characterized by sequential co-occurrences between elements (e.g. These cupcakes are unbelievable), tracking the statistical relationships between these elements is fundamental. However, statistical learning alone cannot fully account for the ability to create abstract rule representations that can be generalized, a paramount requirement of linguistic rules. Here, we provide evidence that, after the statistical relations between words have been extracted, the engagement of goal-directed attention is key to enable rule generalization. Incidental learning performance during a rule-learning task on an artificial language revealed a progressive shift from statistical learning to goal-directed attention. In addition, and consistent with the recruitment of attention, fMRI analyses of late learning stages showed left parietal activity within a broad bilateral dorsal fronto-parietal network. Critically, rTMS on participants peak of activation within the left parietal cortex impaired their ability to generalize learned rules to a structurally analogous new language. No stimulation or rTMS on a non-relevant brain region did not have the same interfering effect on generalization. Performance on an additional attentional task showed that rTMS on the same parietal site hindered participants ability to integrate what (stimulus identity) and when (stimulus timing) information about an expected target. The present findings suggest that learning rules from speech is a two-stage process: following statistical learning, goal-directed attention -involving left parietal regions- integrates what and when stimulus information to facilitate rapid rule generalization.

neuroscience↗