Publications by authors named "Simoncelli E"

Objective: To assess the adherence to the vaccination campaign against SARS-CoV-2 in patients with immunoglobulin-G4-related disease (IgG4-RD) and to evaluate the development of local and systemic adverse events (AEs) following vaccination. Additionally, to investigate the rate and outcome of SARS-CoV-2 infection in IgG4-RD patients.

Methods: Patients with IgG4-RD in follow-up before the onset of the SARS-CoV-2 pandemic were contacted by telephone and asked to answer an ad hoc questionnaire regarding their vaccination status against SARS-CoV-2 and related AEs following vaccination.

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Fixational eye movements alter the number and timing of spikes transmitted from the retina to the brain, but whether these changes enhance or degrade the retinal signal is unclear. To quantify this, we developed a Bayesian method for reconstructing natural images from the recorded spikes of hundreds of retinal ganglion cells (RGCs) in the macaque retina (male), combining a likelihood model for RGC light responses with the natural image prior implicitly embedded in an artificial neural network optimized for denoising. The method matched or surpassed the performance of previous reconstruction algorithms, and provides an interpretable framework for characterizing the retinal signal.

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The visual world is richly adorned with texture, which can serve to delineate important elements of natural scenes. In anesthetized macaque monkeys, selectivity for the statistical features of natural texture is weak in V1, but substantial in V2, suggesting that neuronal activity in V2 might directly support texture perception. To test this, we investigated the relation between single cell activity in macaque V1 and V2 and simultaneously measured behavioral judgments of texture.

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Human ability to recognize complex visual patterns arises through transformations performed by successive areas in the ventral visual cortex. Deep neural networks trained end-to-end for object recognition approach human capabilities, and offer the best descriptions to date of neural responses in the late stages of the hierarchy. But these networks provide a poor account of the early stages, compared to traditional hand-engineered models, or models optimized for coding efficiency or prediction.

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The perception of sensory attributes is often quantified through measurements of sensitivity (the ability to detect small stimulus changes), as well as through direct judgments of appearance or intensity. Despite their ubiquity, the relationship between these two measurements remains controversial and unresolved. Here, we propose a framework in which they arise from different aspects of a common representation.

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We have measured the visually evoked activity of single neurons recorded in areas V1 and V2 of awake, fixating macaque monkeys, and captured their responses with a common computational model. We used a stimulus set composed of "droplets" of localized contrast, band-limited in orientation and spatial frequency; each brief stimulus contained a random superposition of droplets presented in and near the mapped receptive field. We accounted for neuronal responses with a 2-layer linear-nonlinear model, representing each receptive field by a combination of orientation- and scale-selective filters.

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Unlabelled: The visual world is richly adorned with texture, which can serve to delineate important elements of natural scenes. In anesthetized macaque monkeys, selectivity for the statistical features of natural texture is weak in V1, but substantial in V2, suggesting that neuronal activity in V2 might directly support texture perception. To test this, we investigated the relation between single cell activity in macaque V1 and V2 and simultaneously measured behavioral judgments of texture.

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The link between immune cell function and cell metabolic reprogramming is currently known under the term "immunometabolism". Similarly to the Warburg's effect described in cancer cells, in activated immune cells an up-regulation of specific metabolic pathways has been described and seems to be pathogenic in different inflammatory conditions.Sjӧgren's syndrome (SS) is a systemic autoimmune disease that affects the exocrine glands and is characterised by a progressive loss of secretory function.

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Sensory-guided behavior requires reliable encoding of stimulus information in neural populations, and flexible, task-specific readout. The former has been studied extensively, but the latter remains poorly understood. We introduce a theory for adaptive sensory processing based on functionally-targeted stochastic modulation.

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Article Synopsis
  • - The study investigates how environmental factors, specifically climate-related natural hazards, may affect the diagnosis and symptoms of Sjögren's syndrome across different countries, examining aspects like epidemiological profiles and sicca symptoms.
  • - Researchers analyzed data from 16,042 patients in 23 countries, determining that those in countries severely impacted by climate hazards (like extreme precipitation and flooding) were often diagnosed with Sjögren's syndrome earlier and exhibited varying symptom frequencies.
  • - Findings revealed statistically significant patterns, indicating lower occurrences of dry eyes and mouth in patients from countries facing specific climate threats, while showing that increased climate-related risks correlated with higher disease activity scores (ESSDAI).
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Fixational eye movements alter the number and timing of spikes transmitted from the retina to the brain, but whether these changes enhance or degrade the retinal signal is unclear. To quantify this, we developed a Bayesian method for reconstructing natural images from the recorded spikes of hundreds of retinal ganglion cells (RGCs) in the macaque retina (male), combining a likelihood model for RGC light responses with the natural image prior implicitly embedded in an artificial neural network optimized for denoising. The method matched or surpassed the performance of previous reconstruction algorithms, and provides an interpretable framework for characterizing the retinal signal.

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Objectives: Data on the safety of anti-SARS-CoV-2 vaccines in patients with rare rheumatic diseases, such as systemic vasculitis (SV), are limited. The aim of this study was to evaluate the occurrence of a disease flare and the appearance of adverse events (AEs) following administration of anti-SARS-CoV-2 vaccine in a multicentre cohort of patients with SV.

Methods: Patients with SV and healthy controls (HC) from two different Italian rheumatology centres were asked to complete a questionnaire assessing disease flares occurrence, defined as new onset of clinical manifestations related to vasculitis needing an implementation of therapy, and local/systemic AEs appearance following anti SARS-CoV-2 vaccination.

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Neuroscience has long been an essential driver of progress in artificial intelligence (AI). We propose that to accelerate progress in AI, we must invest in fundamental research in NeuroAI. A core component of this is the embodied Turing test, which challenges AI animal models to interact with the sensorimotor world at skill levels akin to their living counterparts.

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Neurons in primate visual cortex (area V1) are tuned for spatial frequency, in a manner that depends on their position in the visual field. Several studies have examined this dependency using functional magnetic resonance imaging (fMRI), reporting preferred spatial frequencies (tuning curve peaks) of V1 voxels as a function of eccentricity, but their results differ by as much as two octaves, presumably owing to differences in stimuli, measurements, and analysis methodology. Here, we characterize spatial frequency tuning at a millimeter resolution within the human primary visual cortex, across stimulus orientation and visual field locations.

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Many sensory-driven behaviors rely on predictions about future states of the environment. Visual input typically evolves along complex temporal trajectories that are difficult to extrapolate. We test the hypothesis that spatial processing mechanisms in the early visual system facilitate prediction by constructing neural representations that follow straighter temporal trajectories.

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Sensory processing necessitates discarding some information in service of preserving and reformatting more behaviorally relevant information. Sensory neurons seem to achieve this by responding selectively to particular combinations of features in their inputs, while averaging over or ignoring irrelevant combinations. Here, we expose the perceptual implications of this tradeoff between selectivity and invariance, using stimuli and tasks that explicitly reveal their opposing effects on discrimination performance.

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Memories of the images that we have seen are thought to be reflected in the reduction of neural responses in high-level visual areas such as inferotemporal (IT) cortex, a phenomenon known as repetition suppression (RS). We challenged this hypothesis with a task that required rhesus monkeys to report whether images were novel or repeated while ignoring variations in contrast, a stimulus attribute that is also known to modulate the overall IT response. The monkeys' behavior was largely contrast invariant, contrary to the predictions of an RS-inspired decoder, which could not distinguish responses to images that are repeated from those that are of lower contrast.

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The performance of objective image quality assessment (IQA) models has been evaluated primarily by comparing model predictions to human quality judgments. Perceptual datasets gathered for this purpose have provided useful benchmarks for improving IQA methods, but their heavy use creates a risk of overfitting. Here, we perform a large-scale comparison of IQA models in terms of their use as objectives for the optimization of image processing algorithms.

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Objective measures of image quality generally operate by comparing pixels of a "degraded" image to those of the original. Relative to human observers, these measures are overly sensitive to resampling of texture regions (e.g.

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Responses of sensory neurons are often modeled using a weighted combination of rectified linear subunits. Since these subunits often cannot be measured directly, a flexible method is needed to infer their properties from the responses of downstream neurons. We present a method for maximum likelihood estimation of subunits by soft-clustering spike-triggered stimuli, and demonstrate its effectiveness in visual neurons.

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Motion selectivity in primary visual cortex (V1) is approximately separable in orientation, spatial frequency, and temporal frequency ("frequency-separable"). Models for area MT neurons posit that their selectivity arises by combining direction-selective V1 afferents whose tuning is organized around a tilted plane in the frequency domain, specifying a particular direction and speed ("velocity-separable"). This construction explains "pattern direction-selective" MT neurons, which are velocity-selective but relatively invariant to spatial structure, including spatial frequency, texture and shape.

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Purpose: To investigate the use of a cold atmospheric plasma (CAP) source in a clinically realistic endodontic procedure to enhance the bond strength of a dental adhesive in root canal restoration.

Materials And Methods: CAP was generated by a handheld DBD-jet prototype specifically designed for biomedical applications. Extracted monoradicular teeth were standardized through crown sectioning and root canal shaping before being embedded in epoxy resin cylinders using a custom molding procedure designed to ensure the accurate alignment of the specimens.

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The original and corrected figures are shown in the accompanying Author Correction.

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Many behaviors rely on predictions derived from recent visual input, but the temporal evolution of those inputs is generally complex and difficult to extrapolate. We propose that the visual system transforms these inputs to follow straighter temporal trajectories. To test this 'temporal straightening' hypothesis, we develop a methodology for estimating the curvature of an internal trajectory from human perceptual judgments.

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Sensory neurons represent stimulus information with sequences of action potentials that differ across repeated measurements. This variability limits the information that can be extracted from momentary observations of a neuron's response. It is often assumed that integrating responses over time mitigates this limitation.

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