Biology subjects

Cuomo, M.

Publications and source records attributed to Cuomo, M..

3 recordsLinked to original sources

bioRxiv2025

The Influence of Spatial Frequencies, Orientation and Familiarity on Face Stimuli Integration

When we observe an object, our visual system identifies its shape and integrates it with specific details to form a coherent representation. This coarse-to-fine approach involves rapid processing of low spatial frequency (LSF) content to generate a basic template, which aids the integration of the more detailed high spatial frequency (HSF) information. Here we explore with two experiments how the contribution of LSF and HSF integration extends to face processing. To do so, we leveraged the face inversion effect, whereby inverted faces are more difficult to recognize than upright ones. In Experiment 1, ten participants matched two familiar faces displayed in rapid succession (template and probe face, respectively). The template and the probe shared either the same SF (congruent) or had complementary SF (incongruent). In congruent conditions, HSF templates yielded better matching accuracy than LSF templates. However, in incongruent conditions, mapping LSF probes onto HSF templates was more effective, but only for upright faces. We propose that, depending on the task, holistic processing may be facilitated by detailed information. In Experiment 2, twelve participants performed the same task with both familiar and unfamiliar faces. While for familiar faces the effects were the same as Experiment 1, for unfamiliar faces the overall accuracy was better for congruent than incongruent conditions, and, crucially, it was independent of the template SF. Our results challenge the view that LSF content provides a foundational template for integrating HSF information, and instead suggest a flexible encoding of SF information, that depends on image contingencies.

neuroscience↗

bioRxiv2024

Contributions of temporal and spatial masking signals in perception of sequential visual events

Accurate perception of time and space is essential for moment-to-moment interactions with our surroundings. This process requires flexibility, as it integrates information from our actions and the external context. Probing the visual system during the updating process reveals spatiotemporal distortions, where sequential stimuli appear closer in time and space than they are. These effects occur perisaccadically or when a visual mask follows the stimuli. The study investigated whether non-overlapping visual masks could influence temporal inversion judgments (TOJs), suggesting that a temporal signal might act as an anchor during updating. In Experiment 1, participants judged the temporal order of two stimuli under three conditions: no mask, a full-field mask, or a partial mask avoiding stimulis locations. Compared to no mask, both masks triggered TOJs when presented within 30 milliseconds of the second stimulus. In a control experiment, delaying mask onset by 30 milliseconds eliminated the inversion effect. In Experiment 2, TOJs were observed for both ipsilateral and contralateral masks, suggesting that long range inhibitory signals might also contribute to the effect. Together, these findings indicate that temporal inversions can occur with non-overlapping stimuli masks configuration, pointing to a non-spatial signal related to mask timing as the underlying mechanism.

neuroscience↗

bioRxiv2022

MC profiling: a novel approach to analyze DNA methylation heterogeneity in genome-wide bisulfite sequencing data

DNA methylation is an epigenetic mark implicated in crucial biological processes. Most of the knowledge about DNA methylation is based on bulk experiments, in which DNA methylation of genomic regions is reported as average methylation. However, average methylation does not inform on how methylated cytosines are distributed in each single DNA molecule. Here, we propose Methylation Class (MC) profiling as a genome-wide approach to the study of DNA methylation heterogeneity from bulk bisulfite sequencing experiments. The proposed approach is built on the concept of MCs, groups of DNA molecules sharing the same number of methylated cytosines. The relative abundances of MCs from sequencing reads incorporates the information on the average methylation, and directly informs on the methylation level of each molecule. By applying our approach to publicly available bisulfite-sequencing datasets, we individuated cell-to-cell differences as the prevalent contributor to methylation heterogeneity. Moreover, we individuated signatures of loci undergoing imprinting and X-inactivation, and highlighted differences between the two processes. When applying MC profiling to compare different conditions, we identified methylation changes occurring in regions with almost constant average methylation. Altogether, our results indicate that MC profiling can provide useful insights on the epigenetic status and its evolution at multiple genomic regions.

bioinformatics↗