Percorrer por autor "Silveira, Celeste"
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- Abnormal habituation of the auditory event-related potential P2 component in patients with schizophreniaPublication . Mazer, Prune; Macedo, Inês; Paiva, Tiago O.; Ferreira-Santos, Fernando; Paison, Rita; Barbosa, Fernando; Almeida, Pedro; Silveira, Celeste; Cunha-Reis, Cassilda; Marques-Teixeira, JoãoAuditory event-related potentials (ERP) may serve as diagnostic tools for schizophrenia and inform on the susceptibility for this condition.Particularly, the examination of N1 and P2 components of the auditory ERP may shed light on the impairments of information processing streams in schizophrenia. However, the habituation properties (i.e., decreasing amplitude with the repeated presentation of an auditory stimulus) of these components remain poorly studied compared to other auditory ERPs.
- Autistic traits and event-related potentials in the general population: A scoping review and meta-analysisPublication . Mazer, Prune; Garcez, Helena; Macedo, Inês; Pasion, Rita; Silveira, Celeste; Sempf, Frederieke; Ferreira-Santos, FernandoDifferences in short and long-latency Event-Related Potentials (ERPs) can help us infer abnormalities in brain processing, considering early and later stages of stimuli processing across tasks and conditions. In autism research, the adult population remains largely understudied compared to samples at early stages of development. In this context, this scoping review briefly summarises what has been described in community and subclinical adult samples of autism. The current scoping review and meta-analysis includes 50 records (N = 1652) and comprehensively explores short and long-latency ERP amplitudes and their relationship with autistic traits in adult community samples. This meta-analysis identified, with small to medium effect sizes, distinctive patterns in late ERP amplitudes, indicating enhanced responses to visual stimuli and the opposite patterns to auditory tasks in the included sample. Additionally, a pattern of higher amplitudes was also found for the component P3b in autistic traits. Differential effects in visual and auditory domains are explored in light of the predictive processing framework for Autism. It remains possible that different brain mechanisms operate to explain symptoms related with different sensory modalities. P3b is discussed as a possible component of interest in future studies as it revealed a more robust effect for differentiating severity in the expression of autistic traits in adulthood
- Systematic review and meta-analysis of the visual mismatch negativity in schizophreniaPublication . Mazer, Prune; Carneiro, Fabio; Domingo, Juan; Pasion, Rita; Silveira, Celeste; Ferreira-Santos, FernandoMismatch negativity (MMN) is an event-related potential component automatically elicited by events that violate predictions based on prior events. To elicit this component, researchers use stimulus repetition to induce predictions, and the MMN is obtained by subtracting the brain response to rare or unpredicted stimuli from that of frequent stimuli. Under the Predictive Processing framework, one increasingly popular interpretation of the mismatch response postulates that MMN represents a prediction error. In this context, the reduced MMN amplitude to auditory stimuli has been considered a potential biomarker of Schizophrenia, representing a reduced prediction error and the inability to update the mental model of the world based on the sensory signals. It is unclear, however, whether this amplitude reduction is specific for auditory events or if the visual MMN reveals a similar pattern in schizophrenia spectrum disorder. This review and meta-analysis aimed to summarise the available literature on the vMMN in schizophrenia. A systematic literature search resulted in 10 eligible studies that resulted in a combined effect size of g = −.63, CI [−.86, −.41], reflecting lower vMMN amplitudes in patients. These results are in line with the findings in the auditory domain. This component offers certain advantages, such as less susceptibility to overlap with components generated by attentional demands. Future studies should use vMMN to explore abnormalities in the Predictive Processing framework in different stages and groups of the SSD and increase the knowledge in the search for biomarkers in schizophrenia.
- Task demand effects on Visual and Auditory MMN across autistic and schizotypal traitsPublication . Mazer, Prune; Pasion, Rita; Rao, Zohra Kamran; Silveira, Celeste; Santos, Fernando Ferreira; Mazer, PruneMismatch negativity (MMN) is an event-related potential component automatically elicited by violations of sensory predictions and is widely interpreted, within the Predictive Processing framework, as a neural correlate of prediction error. Disruptions in prediction error signaling have been proposed as a potential mechanism underlying the diverse cognitive and perceptual profiles observed in autism and schizophrenia spectrum conditions. In this study, 122 community participants completed auditory and visual oddball tasks with two levels of target detection difficulty while undergoing EEG recording, alongside self-report measures of autistic and schizotypal traits. We found that increased task difficulty significantly reduced MMN amplitude in both modalities, with large effect sizes for auditory (d = 1.826) and visual (d = 1.005) MMN, indicating robust modulation by perceptual load. Although associations between MMN amplitude and trait dimensions were limited, emerging patterns suggest a potential dissociation between social and non-social autistic traits. These findings address key gaps in the literature, particularly the underrepresentation of visual MMN, and highlight the importance of multidimensional, cross-modal approaches to investigating prediction error mechanisms in neurodiverse populations.