https://www.pisavisionlab.org Research centre dedicated to frontier, interdisciplinary research of human perception Thu, 10 Sep 2026 09:09:42 +0000 en-US hourly 1 https://wordpress.org/?v=6.4.13 https://www.pisavisionlab.org/2023/11/15/serial-dependence-in-face-gender-classification-revealed-in-low-beta-frequency-eeg/ Wed, 15 Nov 2023 12:01:36 +0000 https://www.pisavisionlab.org/?p=4774 BMC Biology, 23(1), 203. Background Perception depends not only on current sensory input but is also heavily influenced by the immediate past perceptual experience, a phenomenon known as “serial dependence,” particularly robust in face perception. Results We measured discrimination of face-gender in participants to a sequence of intermingled male, female, and androgynous images, while recording EEG responses. The discriminations showed strong serial dependence (androgynous images biased towards male when preceded by male and female when preceded by female). The strength of the bias oscillated over time in the beta range, at 14 Hz for female prior stimuli, 18 Hz for male. Using classification techniques, we were able to successfully classify the previous stimulus from current EEG activity. Classification accuracy correlated well with the strength of serial dependence across individual participants, confirming that the neural signal from the past trial biased face perception. Bandpass filtering of the signal within the beta range showed that the most useful information to classify gender was around 14 Hz when the previous response was “female,” and around 18 Hz when it was “male,” reinforcing the psychophysical results showing serial dependence to be carried at those frequencies. Conclusions Overall, the results suggest that recent experience of face-gender is selectively represented in beta-frequency (14–20 Hz) spectral components of intrinsic neural oscillations. Significance statement The neurophysiological mechanisms of how past perceptual experience affects current perception are poorly understood. Using classification techniques, we demonstrate that the response to gender of the previous face image of a sequence can be decoded from the neural activity of the current EEG response, showing that relevant neural signals are maintained over trials. Classification accuracy was higher for participants with strong serial dependence, strongly implicating these signals as the neural substrate for serial dependence. The best information to classify gender was around 14 Hz for “female” faces, and around 18 Hz for “male,”, reinforcing the psychophysical results showing serial dependence to be carried at those beta -frequencies. Ranieri, G., Burr, D. C., Bell, J., & Morrone, M. C. https://www.pisavisionlab.org/2023/11/15/serial-dependence-in-face-gender-classification-revealed-in-low-beta-frequency-eeg/face-oscillations-bmc/https://doi.org/10.1186/s12915-025-02289-6 https://www.pisavisionlab.org/2025/02/18/reply-to-failure-to-replicate-a-superiority-effect-in-crowding/ Tue, 18 Feb 2025 09:29:12 +0000 https://www.pisavisionlab.org/?p=4999 Nature Communications, 16(1), 1638 replying to A. Ozkirli et al. Nature Communications https://doi.org/10.1038/s41467-025-56762-5 (2025) Cicchini, G. M., D’Errico, G., & Burr, D. C. https://www.pisavisionlab.org/2025/02/18/reply-to-failure-to-replicate-a-superiority-effect-in-crowding/s41467-025-56763-4/https://doi.org/10.1038/s41467-025-56763-4 https://www.pisavisionlab.org/2025/03/26/recent-but-not-long-term-priors-induce-behavioral-oscillations-in-peri-saccadic-vision/ Wed, 26 Mar 2025 11:16:18 +0000 https://www.pisavisionlab.org/?p=5004 Communications Psychology, 3(1), 1–11 Perception of a continuous world relies on our ability to integrate discontinuous sensory signals when we make saccadic eye movements, which abruptly change the retinal image. Here we investigate the role of oscillations in integrating pre-saccadic information with the current sensory signals. We presented to participants (N = 24) a brief pre-saccadic Gabor stimulus (termed the inducer) before voluntary 16° saccades, followed by a test Gabor stimulus at various times before or after saccadic onset. Orientation judgments of the test stimulus were biased towards the orientation of both the inducer and previous (1-back) test stimulus, consistent with serial dependence. In addition to the average bias, judgments oscillated in synchrony with saccadic onset at alpha frequencies (~9.5 Hz) towards the orientation of the inducer or 1-back stimulus. There was also a strong bias towards the mean orientation (central tendency): however, that bias was constant over time, not associated with saccade-synched oscillations. Perceptual oscillations in serial dependence (but not central tendency) suggest that alpha rhythms may be instrumental in communicating short-term (but not long-term) perceptual memory across saccades, helping to preserve stability during saccades. The distinction between the modes of communicating short- and long-term memory suggests that the two phenomena are mediated by distinct neuronal circuitry. Xie, X.-Y., Burr, D. C., & Morrone, M. C. https://www.pisavisionlab.org/2025/03/26/recent-but-not-long-term-priors-induce-behavioral-oscillations-in-peri-saccadic-vision/s44271-025-00224-7/https://doi.org/10.1038/s44271-025-00224-7 https://www.pisavisionlab.org/2025/03/26/the-visual-system-does-not-operate-like-a-camera/ Wed, 26 Mar 2025 11:23:03 +0000 https://www.pisavisionlab.org/?p=5007 Journal of Vision, 25(3), 2 We welcome the editors’ invitation to reply to Dr. Gur’s Perspective (Gur, 2024), in which he argues that visual perception is entirely driven by snapshot images resulting from saccade landings and against the idea that vision is a dynamic process that incorporates information present in the temporal transients delivered by all kinds of eye movements. In Gur’s Opinion, saccade landings act as image flashes and elicit neural responses that dominate the entire periods of fixation, so that, contrary to recent findings, the small eye movements that continually occur during fixation serve no perceptual function. Unfortunately, Gur’s Perspective is affected by numerous flaws, including the neglect of a large body of literature, misconceptions concerning proposed dynamic theories, inaccurate portrayals of eye movements and neural responses, arbitrary and unjustified assumptions on neural processing, erroneous interpretations, and multiple factual errors concerning previous experimental findings and procedures. Practically every point raised against dynamic theories, and almost every point raised in favor of saccade landing acting as an instantaneous flash, contains inaccuracies and/or misplaced assumptions. Once these errors are recognized, Gur’s proposal becomes baseless and illogical. This letter aims to clarify the major misconceptions present in Gur’s Perspective and correct the most glaring inaccuracies. In Gur’s defense, we acknowledge that his Perspective follows the traditional camera-like view of the visual system, the pervasive view based on explicit spatial processing and representations that match naïve introspection. Because many readers may only be familiar with this textbook view, we briefly summarize the concepts of dynamical vision before addressing Gur’s Perspective. Recognizing that vision relies on the dynamic signals provided by all kinds of eye (and body) movements opens up important new areas for experimental and theoretical studies, including the extent to which eye movements can be tuned and controlled to improve performance, how these control signals are naturally generated, and how planning, oculomotor, and visual signals interact. Rucci, M., Ahissar, E., Burr, D. C., Kagan, I., Poletti, M., & Victor, J. D. https://www.pisavisionlab.org/2025/03/26/the-visual-system-does-not-operate-like-a-camera/i1534-7362-25-3-2_1741083445-63362/https://doi.org/10.1167/jov.25.3.2 https://www.pisavisionlab.org/2025/04/22/pupil-size-as-a-biomarker-of-cognitive-dysfunctions-toward-a-physiologically-informed-screening-of-mental-states/ Tue, 22 Apr 2025 10:59:26 +0000 https://www.pisavisionlab.org/?p=5041 Acta Psychologica The objective assessment of cognitive processes is of critical importance to understanding the mechanisms underlying various mental functions and dysfunctions. In recent years, the technological innovations related to the eye-tracking industry made the time right to organically integrate pupillometry in the assessment of cognitive profiles. Here, we review evidence showing that pupillometry offers a uniquely sensitive biomarker of the functioning of several distinct networks, cognitive functions, emotional states, and individual differences in their instantiation. We outline why and how pupillometry can be effectively exploited to enrich current research and behavioral paradigms, including those designed for clinical testing. By making the cases of anxiety disorders (both generalized and specific - e.g., generalized anxiety vs. math anxiety) and substance use disorders, we then exemplify how pupillometry can be leveraged to obtain clinically meaningful variables. We finally conclude by arguing that measuring pupil size has the potential to complement more traditional, but coarse assessment methods, to return a more graded, objective, and physiologically informed picture of cognitive functioning. Serena Castellotti, Elisa Castaldi, Elvio Blini, & Roberto Arrighi https://www.pisavisionlab.org/2025/04/22/pupil-size-as-a-biomarker-of-cognitive-dysfunctions-toward-a-physiologically-informed-screening-of-mental-states/castellotti2025_pupilreview/ https://doi.org/10.1016/j.actpsy.2025.104720 https://www.pisavisionlab.org/2025/07/09/optimal-feature-encoding-in-early-vision/ Wed, 09 Jul 2025 12:47:12 +0000 https://www.pisavisionlab.org/?p=5081 Scientific Reports The human visual system processes a massive amount of visual information very rapidly, requiring efficient coding mechanisms to handle such data within physiological constraints. The biological foundations of these mechanisms remain poorly understood. One hypothesis suggests that the visual system prioritizes the encoding of specific features of natural scenes optimized to maximize information transfer while minimizing computational costs (constrained-maximum entropy criteria). This study aims to identify a possible neural marker of this prioritizing mechanism. Participants were briefly shown stimuli with varying proportions of such optimal features, while EEG visual evoked response was recorded. Analysis focused on the C1 component, the earliest visual evoked component commonly considered to mainly reflect the first cortical response in the primary visual cortex (V1). Results revealed that the C1 component peaks earlier when elicited by optimal features, with a proportional speed-up following the gradual increase of their number. This provides evidence for an early efficient selection of optimally informative visual features in humans. Serena Castellotti, Giacomo Mazzotta, Alessandro Benedetto, & Maria Del Viva https://www.pisavisionlab.org/2025/07/09/optimal-feature-encoding-in-early-vision/castellotti-2025_eeg/https://doi.org/10.1038/s41598-025-07644-9 https://www.pisavisionlab.org/2025/07/29/continuous-tracking-of-audiovisual-motion/ Tue, 29 Jul 2025 14:00:56 +0000 https://www.pisavisionlab.org/?p=5085 Journal of Vision (2025) 0(0):09256, 1–16 Multisensory processing is important for studying and understanding typical and atypical development; however, traditional paradigms involve numerous conditions and trials, making sessions long and tedious. A technique referred to as “continuous-tracking” has been introduced which can assess perceptual thresholds in a shorter time. We tested this technique in an audiovisual context by asking participants to track 1-minute audiovisual stimuli moving in a random walk. The stimuli could be visual, auditory, or audiovisual. In the last case, we had a congruent and incongruent condition with a spatiotemporal shift between the two stimuli, so either vision or audition led the walk by a given time. We further modulated the reliability of the visual stimulus to shift the weight toward the audio. We found a straightforward visual dominance regarding motion perception in audiovisual contexts. Regardless of its state, visual information interferes with auditory perception. Moreover, the continuous tracking yielded a new measurement of motion perception, the lag, giving information on the delay between visual and auditory information processing. Indeed, we observed that the tracking of auditory motion lagged relative to visual motion. Tonelli, A., Burr, D. C., Gori, Monica, M., & Alais, D. https://www.pisavisionlab.org/2025/07/29/continuous-tracking-of-audiovisual-motion/jov-09256-2024_lr/https://doi.org/10.1167/jov.0.0.09256 https://www.pisavisionlab.org/2025/07/29/multisensory-number-channels-derived-from-individual-differences/ Tue, 29 Jul 2025 14:08:45 +0000 https://www.pisavisionlab.org/?p=5088 Multisensory Research Recently, analysis of differences in individual performance has provided evidence to support the existence of sensorimotor number mechanisms. The individual difference technique assumes that performance for stimuli processed by the same mechanism should be more correlated between individuals than are stimuli processed by different mechanisms. Here we replicated this finding and generalized the results to other sensory modalities. We measured performance for the same participants on three different numerical tasks: a sensorimotor task (series of actions), a temporal numerosity task (series of flashes) and a spatial numerosity task (array of dots). We then searched for tuning selectivity within each task and between task pairs by analysing patterns of correlation between tested numerosities. Correlation within each task showed tuning selectivity in all the three cases, with high positive correlations for nearby target numbers that decreased with numerical distance, providing psychophysical and physiological evidence for the existence of multisensory numerosity channels. Cross-task correlations also suggested a shared tuning between the sensorimotor and temporal visual numerosity, which points to channels responsible for performance in both visual and motor temporal number tasks. However, no shared tuning emerged between spatial visual numerosity and the other two tasks, suggesting partially different patterns of encoding for temporal and spatial numerosity. Taken together our results provide evidence for a similar functional architecture for the three tasks tested here, but also imply that there is no full overlap of shared resources between numerosity domains, suggesting at least partially separated mechanisms of encoding. Petrizzo, I., Cicchini, G. M., Burr, D. C., & Anobile, G. https://www.pisavisionlab.org/2025/07/29/multisensory-number-channels-derived-from-individual-differences/msr-article-10-1163-22134808-bja10154/https://doi.org/10.1163/22134808-bja10154 https://www.pisavisionlab.org/2025/07/29/the-speed-of-visual-discrimination-differs-between-foveola-and-perifovea-a-combined-eeg-and-behavioral-investigation/ Tue, 29 Jul 2025 14:12:41 +0000 https://www.pisavisionlab.org/?p=5091 eNeuro Despite the vivid experience of homogeneous vision, our visual system is inherently endowed with highly inhomogeneous structures. Although the temporal characteristics of visual responses vary with eccentricity, the connection between this variation, the speed of visual processing, and its underlying neurophysiological mechanisms remains a topic of debate. Here, we performed simultaneous recordings of high-precision gaze positions and EEG activity to investigate how foveal and perifoveal stimulation impact reaction times (RTs) and visual evoked potentials (VEPs). Volunteers discriminated the position and orientation of a U-shaped figure with the aperture facing either upward or downward. Stimuli were presented briefly (50ms) either in the foveola (0.33°) or perifovea (6.5°), to the right or left of the fixation point. Stimulus size in the perifovea condition was adjusted according to the cortical magnification factor (stimulus size: 0.2° and 0.75° for the foveola and perifovea condition, respectively). When stimuli were equated for sensitivity and cortical area of stimulation, we observed faster RTs in the perifovea condition (16.8 ± 4ms) compared to the foveola. The analysis of the VEP revealed a similar effect for the N1 response (11.0 ± 4ms), a parieto-occipital component associated with discriminative processing and influenced by spatial attention. Overall, our findings suggest that visual discrimination speeds vary across eccentricities, with faster processing and shorter latency of early visual responses in the perifovea compared to the foveola. Significant Statement This study investigates how visual processing speeds vary with eccentricity. By recording high-precision gaze positions and EEG activity, we asked volunteers to discriminate the orientation of a U-shaped figure briefly presented foveally or perifoveally. We found that visual stimuli presented perifoveally led to faster reaction times and shorter visual evoked potentials compared to a foveal presentation. In particular, reaction times for perifoveal stimuli were faster by 16.8 ± 4ms, with similar effects observed in the N1 VEP component (11.0 ± 4ms). These findings suggest that early visual processing is quicker in the perifovea, highlighting the presence of effective temporal inhomogeneities across the retina. Benedetto, A., Jenks, S. K., Mishra, M. V., Giesbrecht, B., & Poletti, M. https://www.pisavisionlab.org/2025/07/29/the-speed-of-visual-discrimination-differs-between-foveola-and-perifovea-a-combined-eeg-and-behavioral-investigation/eneuro-0078-25-2025-full/https://doi.org/10.1523/ENEURO.0078-25.2025 https://www.pisavisionlab.org/2025/08/01/pupillometric-signature-of-implicit-learning-of-statistical-regularities/ Fri, 01 Aug 2025 13:19:39 +0000 https://www.pisavisionlab.org/?p=5094

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Current Biology Animals learn about the statistical regularities of their environment by a process of implicit learning, a power- ful mechanism that may operate by mere exposure.1 Implicit learning supports processes such as speech acquisition but also learning about the spatial and temporal structure of the world more generally, which is essential for effective interaction.2 Here, we used a frequency-tagging technique to demonstrate a pupillo- metric signature of the learning of the temporal structure (pairing of numerosities) of sequential arrays. Although the numerosity pairings were unnoticed by all participants, the pupil responded clearly to their repe- tition frequency (1 Hz). Pupillometry allowed us to track the learning as it unfolded (the response became sig- nificant after less than 3 min of passive viewing), without ever directing attention to the temporal structure of the stimuli. Diverting attention away from the numerosity feature did not prevent learning, but it did affect the dynamics of the response acquisition. A clear pupillometric response was also elicited by pairing dyads of digits. In all our stimuli, the local features were randomized, implying that learning successfully generalized across stimuli that were locally different and only acquired a temporal structure once their global statistics (overall shape or numerosity) were extracted. Binda P., Terzo C., Turi M., & Burr D.C. https://www.pisavisionlab.org/2025/08/01/pupillometric-signature-of-implicit-learning-of-statistical-regularities/1-s2-0-s0960982225001459-main/https://doi.org/10.1016/j.cub.2025.02.011 https://www.pisavisionlab.org/2025/08/22/continuous-tracking-of-audiovisual-motion-2/ Fri, 22 Aug 2025 08:10:21 +0000 https://www.pisavisionlab.org/?p=5164 Journal of Vision, 25(10), 10. Multisensory processing is important for studying and understanding typical and atypical development; however, traditional paradigms involve numerous conditions and trials, making sessions long and tedious. A technique referred to as “continuous-tracking” has been introduced which can assess perceptual thresholds in a shorter time. We tested this technique in an audiovisual context by asking participants to track 1-minute audiovisual stimuli moving in a random walk. The stimuli could be visual, auditory, or audiovisual. In the last case, we had a congruent and incongruent condition with a spatiotemporal shift between the two stimuli, so either vision or audition led the walk by a given time. We further modulated the reliability of the visual stimulus to shift the weight toward the audio. We found a straightforward visual dominance regarding motion perception in audiovisual contexts. Regardless of its state, visual information interferes with auditory perception. Moreover, the continuous tracking yielded a new measurement of motion perception, the lag, giving information on the delay between visual and auditory information processing. Indeed, we observed that the tracking of auditory motion lagged relative to visual motion. Tonelli, A., Burr, D., Gori, M., & Alais, D. https://www.pisavisionlab.org/2025/08/22/continuous-tracking-of-audiovisual-motion-2/i1534-7362-25-10-10_1755613426-65435/https://doi.org/10.1167/jov.25.10.10 https://www.pisavisionlab.org/2025/11/05/acute-supplementation-of-beta-hydroxybutyrateincreasesvisual-cortical-excitability-in-humans-a-combinedelectro-encephalographyand-magnetic-resonancespectroscopy-study/ Wed, 05 Nov 2025 14:20:26 +0000 https://www.pisavisionlab.org/?p=5213 European Journal of Neuroscience Increasing plasma levels of ketone bodies via supplementation has been recently found to modulate the neurometabolic profilein the healthy human brain. Here, we aimed to explore the physiological consequences of these neurometabolic changes by as-sessing visual cortical function. Ten young adult human volunteers (mean age 27 years, range 23–34) were orally administereda single dose of a β-hydroxybutyrate (βHB) ester (one of the main ketone bodies), and we measured neurometabolic changeafter supplementation. We used Electroencephalography (EEG) to assess cortical responsivity to visual stimuli and endogenousrhythms, and magnetic resonance spectroscopy (MRS) to quantify glutamate and GABA+ concentrations in the occipital cortex.βHB supplementation increased the amplitude of steady-state visual evoked potentials and increased resting-state EEG alphapower (8–13 Hz). These electrophysiological changes were paralleled by an increase in glutamate (but not GABA+) concentrationin the occipital cortex. The glutamate increase was correlated with the increased steady-state visual evoked potentials amplitude.This suggests that acute βHB supplementation increases the excitability of the brain cortex, as assessed neurometabolically andelectrophysiologically. We discuss how these effects of acute supplementation may differ from the long-term effects of chronicinterventions in healthy or pathological brains. Cecilia Steinwurzel, Maria Concetta Morrone, Ele Ferrannini, Francesca Frijia, Domenico Montanaro, Giuseppe Daniele, Paola Binda https://www.pisavisionlab.org/2025/11/05/acute-supplementation-of-beta-hydroxybutyrateincreasesvisual-cortical-excitability-in-humans-a-combinedelectro-encephalographyand-magnetic-resonancespectroscopy-study/eur-j-of-neuroscience-2025-steinwurzel-acute-supplementation-of-beta%e2%80%90hydroxybutyrate-increases-visual-cortical-2/https://doi.org/10.1111/ejn.70270 https://www.pisavisionlab.org/2025/11/05/short-term-monocular-deprivation-in-adult-humans-ameta-analysis-and-new-perspectives/ Wed, 05 Nov 2025 14:36:06 +0000 https://www.pisavisionlab.org/?p=5216 ["talk"] Vision Sciences Society Few hours of monocular deprivation in adult humans results in a transient shift of ocular dominance in favor of the deprived eye. This robust phenomenon has been investigated with several methodologies in 75 studies since 2011. We compiled a metaanalysis of these studies, structured following the PRISMA checklist and selectively including studies on healthy humans. Each study includes multiple experiments (approximately 180); for each, we computed a standardized effect size and, where possible, we quantified the decay rate of the effect. In the majority of studies, deprivation was achieved by covering one eye with an opaque or a translucent patch, with comparable outcomes (two-sample t(108) = -0.02, p = 0.98). Deprivation effects were mainly measured with three types of tasks: binocular cooperation, binocular competition, and monocular thresholds. Effects are larger when measured with binocular cooperation compared to binocular competition (two-sample t(100) = 4.66, p = 0.001), possibly reflecting different time windows used to report the average effects. Longer periods of deprivation induce larger (r(107) = 0.32, p = 0.001) and longer lasting effects (r(38) = 0.38, p = 0.020). Patching either eye (dominant or nondominant) does not significantly affect the outcome (two-sample t(98) = -0.74, p = 0.46). Effects are seen for both eyes; however, pooling data across studies, we find that opaque patching primarily triggers a suppression of the non-deprived eye, while translucent patching primarily boosts the deprived one (paired t(31) = 2.99, p = 0.005). A growing number of studies show that monocular deprivation effects can be mimicked by manipulations that do not impact the strength of the monocular signal, including degradation of image quality (pink noise, kaleidoscope), image inversion in space or time, or monocular delay. We conclude that the observed shift in eye dominance results from a complex interplay between bottom-up visual stimulation and top-down signals. 20/05/2025 20/05/2025 Cecilia Steinwurzel, Giacomo Pennella , Claudia Lunghi , Paola Binda https://www.pisavisionlab.org/2025/11/05/short-term-monocular-deprivation-in-adult-humans-ameta-analysis-and-new-perspectives/talk_vss-presentation/ https://www.pisavisionlab.org/2025/11/05/short-term-monocular-deprivation-changes-thalamo-cortical-connectivity-measured-with-ultra-high-field-fmriduring-visual-stimulation/ Wed, 05 Nov 2025 14:44:39 +0000 https://www.pisavisionlab.org/?p=5221 ["poster"] Vision Sciences Society In adult humans, brief periods of monocular deprivation induce ocular dominance plasticity, transiently enhancing responses to stimuli in the deprived eye in the primary visual cortex V1 (Binda et al., 2018) and the ventral pulvinar (Kurzawski et al., 2022). Prior work (Acquafredda et al., VSS2023) suggests that these changes are accompanied by a functional reorganization of visual processing circuits, particularly cortico-pulvino-cortical loops, measured in resting-state. Here we investigated how thalamocortical connectivity is modulated by visual stimulation of either eye, before and after deprivation. We acquired ultra-high-field 7T fMRI EPI sequences from 22 normally sighted adults, pre- and post-2 hours of monocular deprivation. Participants were presented with monocular band-pass noise stimuli with five contrast levels. BOLD responses were analyzed for three regions of interest: V1, lateral geniculate nucleus, and pulvinar. Their effective connectivity was assessed by Dynamic Causal Modeling (Tapas toolbox, Frassle et al., 2017). Post-deprivation, V1 evoked responses increased for the deprived eye and decreased for the non-deprived eye, and the modulation was stronger for higher contrast stimuli, consistent with a response gain change. During deprived eye stimulation, pulvinar-to-V1 effective connectivity decreased post-deprivation (like in the resting state) while the V1-pulvinar connectivity remained constant. During stimulation of the non-deprived eye, the opposite connectivity changes were observed. These results suggest that monocular deprivation produces a disconnection between pulvinar and V1, probably decreasing V1 top-down modulation. The mirror-symmetric effect for the non-deprived eye recapitulates the symmetric modulation observed psychophysically. Overall, resting state and visual-evoked results suggest that brief periods of monocular deprivation produce changes in visual processing that extend beyond local V1 processes and may reflect a reorganization of top-down visual influence in V1. 17/05/2025 17/05/2025 Miriam Acquafredda , Cecilia Barachini , Laura Biagi , Michela Tosetti , Maria Concetta Morrone , Paola Binda https://www.pisavisionlab.org/2025/11/05/short-term-monocular-deprivation-changes-thalamo-cortical-connectivity-measured-with-ultra-high-field-fmriduring-visual-stimulation/poster_vss-presentation/ https://www.pisavisionlab.org/2025/11/18/monocular-delay-during-visually-guided-actions-is-as-effective-as-monocular-deprivation-in-driving-ocular-dominance-plasticity/ Tue, 18 Nov 2025 10:37:22 +0000 https://www.pisavisionlab.org/?p=5236 Scientific Reports In normally sighted adult volunteers, applying a monocular patch for a few hours produces a short-term shift of ocular dominance in favor of the deprived eye—a phenomenon often interpreted as a form of homeostatic plasticity. We recently showed that the same effect can be elicited without eye-patching, by delaying the image in one eye (by 333 ms) over a 1 h period, during which participants engaged in a visuomotor coordination task; at the end of this period, ocular dominance shifted in favor of the delayed eye. Here we extended these findings, showing that passive exposure to the dichoptic replay of the same video with the same monocular delay did not affect ocular dominance. Moreover, we showed that the ocular dominance shift elicited by monocular delay during goal-directed actions had the same size as the effect of monocular deprivation, achieved by replacing the delayed image with a homogeneous gray screen, and that the two effects were correlated across participants. These results suggest that homeostatic plasticity is gated by a mismatch between vision in one eye and its multimodal context, and it is not necessarily linked with visual deprivation. Cecilia Steinwurzel, Giacomo Pennella, Maria Concetta Morrone, Giulio Sandini, Paola Binda https://www.pisavisionlab.org/2025/11/18/monocular-delay-during-visually-guided-actions-is-as-effective-as-monocular-deprivation-in-driving-ocular-dominance-plasticity/monocular_delay_during_visually_guided_actions_is_/https://doi.org/10.1038/s41598-025-18464-2 https://www.pisavisionlab.org/2025/11/27/visual-search-performance-depends-on-the-congruency-of-olfactory-sensations/ Thu, 27 Nov 2025 15:58:56 +0000 https://www.pisavisionlab.org/?p=5240 Scientific Reports We here provide evidence for a benefit of congruent olfactory sensations during a challenging visual search task. Using a four-channel olfactometer, we exposed our participants to one of three suprathreshold fruit odorants (lemon, apple, or strawberry) or neutral room air (no odorant) while they searched for an image of a cued-target fruit presented among fruit distractors. Congruent odorants (e.g., exposure to a lemon scent while searching for a lemon among other fruits) led to greater performance levels and faster responses compared to trials where the participants were exposed to an odorant that was incongruent to the searched-for target fruit or to neutral room air, respectively. Post-hoc correlations across our n=22 participants suggest that low performers in the baseline (no-odorant) search task benefited most from the congruent odorant-visual object coupling, whereas the visual search of high performers was impaired most by incongruent couplings. A control task points to large individual differences in olfactory discrimination across our healthy participants and their discriminative ability correlates with the amplitude and sign of the congruency effect. Our findings point to a multisensory congruency effect of odorant processing while participants visually search for a nutritional item among other food choices, suggesting that your nose knows what you are looking for. Serena Castellotti, Marija Soldo, Tina Plank, Maria Del Viva, & Mark Greenlee https://www.pisavisionlab.org/2025/11/27/visual-search-performance-depends-on-the-congruency-of-olfactory-sensations/castellotti2025_smell/https://doi.org/10.1038/s41598-025-25995-1 https://www.pisavisionlab.org/2025/11/27/dimensionality-reduction-techniques-in-pupillometry-research-a-primer-for-behavioral-scientists/ Thu, 27 Nov 2025 16:06:32 +0000 https://www.pisavisionlab.org/?p=5243 Behavior Research Methods The measurement of pupil size is a classic tool in psychophysiology, but its popularity has recently surged due to the rapid developments of the eye-tracking industry. Concurrently, several authors have outlined a wealth of strategies for tackling pupillary recordings analytically. The consensus is that the “temporal” aspect of changes in pupil size are key, and that the analytical approach should be mindful of the temporal factor. Here we take a more radical stance on the matter by suggesting that, by the time significant changes in pupil size are detected, it is already too late. We suggest that these changes are indeed the result of distinct, core physiological processes that originate several hundreds of milliseconds before that moment and altogether shape the observed signal. These processes can be recovered indirectly by leveraging on dimensionality reduction techniques. Here we therefore outline key concepts of temporal principal components analysis and related rotations to show that they reveal a latent, low-dimensional space that represents these processes very efficiently: a pupillary manifold. We elaborate on why assessing the pupillary manifold provides an alternative, appealing analytic solution for data analysis. In particular, dimensionality reduction returns scores that are: 1) mindful of the relevant physiology underlying the observed changes in pupil size, 2) extremely handy and manageable for statistical modelling, and 3) devoided of several arbitrary choices. We elaborate on these points in the form of a tutorial paper for the functions provided in the accompanying R library “Pupilla”. Serena Castellotti, Irene Petrizzo, Roberto Arrighi, & Elvio Blini https://www.pisavisionlab.org/2025/11/27/dimensionality-reduction-techniques-in-pupillometry-research-a-primer-for-behavioral-scientists/castellotti2025_pupiltoolbox/https://doi.org/10.3758/s13428-025-02786-0 https://www.pisavisionlab.org/2025/11/27/art-induced-psychological-well-being-individual-traits-shape-the-beneficial-effects-of-aesthetic-experiences/ Thu, 27 Nov 2025 16:18:02 +0000 https://www.pisavisionlab.org/?p=5247 PLOS ONE Since the beginning of the last century, a wide variety of studies have provided evidence of the role of art in improving health and well-being. In this study, we engaged 92 young adults in a guided tour of a contemporary art exhibition, centered around human freedom themes, offering an immersive multi-sensory experience. We aim to discover potential immediate beneficial effects of such aesthetic experience on anxiety, empathy, and compassion, and investigate how these effects relate to visitors’ psychological traits. We also studied whether individual characteristics could explain differences in visitors’ behavioral responses – i.e., visit time and post-visit evaluations. Prior to the experience, we collected participants' information about their art preferences, interests, and expertise, and assessed their psychological traits of curiosity, openness to experience, anxiety, empathy, and compassion. The visit was led by an expert guide, and participants’ behavior was recorded through mobile eye tracking. Standardized self-report scales were administered before and after the visit to measure art-induced benefits on psychological well-being. An ad-hoc post-visit questionnaire, including several dimensions (beauty, understanding, satisfaction, etc.), was finally administered. Results showed that state anxiety decreased following the visit, particularly among visitors with a high trait of anxiety. Empathic and compassionate feelings increased after the visit, particularly among visitors with initially low empathic abilities and low compassion for humanity. Participants with higher curiosity and openness traits tended to spend more time engaging with the artworks and gave overall more positive evaluations. Higher art-related dimensions were linked to stronger emotional reactions and a greater sense of satisfaction and personal enrichment. Our findings provide additional evidence of the impact of art enjoyment on well-being. Art experiences centered around deeply emotional human themes may indeed reduce anxiety and enhance other-oriented feelings. Importantly, psychological traits define clusters of people who may benefit more from experiencing such art exhibitions. Serena Castellotti, Elisa Gragnoli, Giada Baglioni, Roberta Criminisi, Barbara Giangrasso, & Maria Del Viva https://doi.org/10.1371/journal. pone.0332321 https://www.pisavisionlab.org/2025/12/16/the-pulvinar-regulates-plasticity-in-human-visual-cortex/ Tue, 16 Dec 2025 09:29:44 +0000 https://www.pisavisionlab.org/?p=5264 Science Advances In normally sighted human adults, 2 hours of monocular deprivation is sufficient to transiently alter ocular dominance. Here, we show that this is associated with a reduction of functional connectivity between the pulvinar and primary visual cortex (V1), selective for the pulvinar-to- V1 directionality. Across participants, the strength of the pulvinar-to- V1 connectivity was negatively correlated with the ocular dominance shift, implying less plasticity in participants with stronger influence of the pulvinar over V1. Our results support a revised model of adult V1 plasticity, where short-term reorganization is gated by modulatory signals relayed by the pulvinar. Miriam Acquafredda, Jan W. Kurzawski, Laura Biagi, Michela Tosetti, Maria Concetta Morrone, Paola Binda https://www.pisavisionlab.org/2025/12/16/the-pulvinar-regulates-plasticity-in-human-visual-cortex/sciadv-adw9988/https://doi.org/10.1126/sciadv.adw9988 https://www.pisavisionlab.org/2026/06/12/virtual-reality-as-an-innovative-tool-for-numerosity-perception/ Fri, 12 Jun 2026 07:36:30 +0000 https://www.pisavisionlab.org/?p=5344 Applied Sciences, 15(7), 3976 Numeracy, the ability to use basic mathematical skills in everyday life, is essential in modern society. Recent studies have shown a connection between numeracy and visual numerosity perception, yet traditional 2D screen-based assessment methods often lack ecological validity and participant engagement. This study evaluates the viability of conducting numerosity estimation tasks in virtual reality (VR) and to determine whether hallmarks of numerosity processing, typically observed in laboratory settings, can be replicated in immersive environments. Six participants completed a psychophysical evaluation in VR, comparing the numerosity of visual stimuli consisting of two sets of spheres. The VR experiment successfully replicated two distinctive patterns found in traditional psychophysical studies: increased precision and decreased response times at high numerosities. Specifically, Weber fractions drop by approximately a factor of two, with values ranging from ~15% for low and intermediate conditions to ~8% in high numerosities, and response times decreases from ~663 ms for low numerosities to ~593 ms for high numerosities. These findings highlight that VR can be effectively used for numerosity estimation tasks, providing a controlled and immersive environment that traditional methods cannot achieve, while significantly expanding methodological possibilities in psychophysical research. Aruanno, B., Anobile, G., Razionale, A. V., Bordegoni, M., & Cicchini, G. M. https://www.pisavisionlab.org/2026/06/12/virtual-reality-as-an-innovative-tool-for-numerosity-perception/applsci-15-03976-v2/https://doi.org/10.3390/app15073976 https://www.pisavisionlab.org/2026/06/12/the-role-of-physical-and-cognitive-effort-on-time-perception/ Fri, 12 Jun 2026 07:39:40 +0000 https://www.pisavisionlab.org/?p=5347 Scientific Reports, 15(1), 25595 Action and perception are intertwined, and time perception is not an exception to this general principle. In line with that, we have recently reported that the perceived duration of visual stimuli is extended while running. Here we tested the nature of this phenomenon by contrasting two possibilities: one related to physiological changes induced by physical effort (e.g. heart rate, temperature, arousal), and one related to cognitive alterations linked to motor control. To this aim we compared the direction and magnitude of the temporal bias induced by running to that prompted by other two conditions requiring much lower physical effort but both depleting cognitive resources. In these two conditions, participants either performed the timing task while walking backwards (an attentional motor task) or standing still with cognitive resources divided in a concurrent visual-working memory task. Both conditions yielded temporal overestimations virtually identical to that found while running, suggesting that physical activity could modulate temporal processing through the cognitive effort required to perform/control that specific motor routine. The results are informative for the scientific community investigating time perception in ecological sensorimotor contexts, suggesting the importance of considering the potential confounding role of cognitive factors related to motor execution. Bartolini, T., Petrizzo, I., Arrighi, R., & Anobile, G. https://www.pisavisionlab.org/2026/06/12/the-role-of-physical-and-cognitive-effort-on-time-perception/s41598-025-07814-9/https://doi.org/10.1038/s41598-025-07814-9 https://www.pisavisionlab.org/2026/06/12/stronger-reliance-on-visual-perceptual-history-in-individuals-with-higher-math-anxiety/ Fri, 12 Jun 2026 07:43:05 +0000 https://www.pisavisionlab.org/?p=5350 BMC Biology, 23(1), 305 Perception is inferential, relying not only on current sensory input but also on prior knowledge. When sensory input is unreliable, history effects such as central tendency and serial dependence smooth out noise by combining previous and current stimuli. These processes support perceptual continuity but also introduce biases, making the current stimulus appear erroneously similar to the previous one. Despite being observed in many perceptual domains, the mechanisms underlying these dynamic processes remain debated. Although perceptual, cognitive, and developmental factors have been studied, the influence of psychological traits has received little attention. In this study, we compared serial dependence and central tendency effects measured with a visual numerosity task across individuals with different levels of math anxiety. Burgio, I., Moscoso, P. A. M., Anobile, G., & Castaldi, E. https://www.pisavisionlab.org/2026/06/12/stronger-reliance-on-visual-perceptual-history-in-individuals-with-higher-math-anxiety/s12915-025-02417-2/https://doi.org/10.1186/s12915-025-02417-2 https://www.pisavisionlab.org/2026/06/12/color-selective-numerosity-adaptation-depends-on-the-automatic-categorization-of-colored-information/ Fri, 12 Jun 2026 07:52:08 +0000 https://www.pisavisionlab.org/?p=5358 iScience, 28(6), 112572 Numerosity perception is subject to adaptation, but this effect is greatly reduced when adaptor and test differ in color. This color-selectivity has been interpreted as evidence of automatic categorization of color-defined numerical information. However, some argue it instead demonstrates the non-numerical nature of numerosity adaptation. According to this idea numerosity adaptation is a byproduct of low-level filtering of spatial and chromatic information. Here, we contrasted these two perspectives by probing numerosity adaptation and its selectivity to color after equating stimuli in terms of their probability to be filtered out and by directly testing the role of categorization mechanisms in the genesis of color-selective adaptation behaviors. Our results confirm that numerosity adaptation does not depend on the filtering out of visual information and suggest that its selectivity for color genuinely reflects the visual system’s ability to automatically parse between categories when these are defined by salient visual attributes like color. Grasso, P. A., Anobile, G., Gurioli, M., Cicchini, G. M., & Arrighi, R. https://www.pisavisionlab.org/2026/06/12/color-selective-numerosity-adaptation-depends-on-the-automatic-categorization-of-colored-information/piis2589004225008338/https://doi.org/10.1016/j.isci.2025.112572 https://www.pisavisionlab.org/2026/06/12/groupitizing-a-visuo-spatial-and-arithmetic-phenomenon/ Fri, 12 Jun 2026 07:54:52 +0000 https://www.pisavisionlab.org/?p=5361 Open Mind: Discoveries in Cognitive Science, 9, 121–137. When objects are grouped in space, humans can estimate numerosity more precisely than when they are randomly scattered. This phenomenon, called groupitizing, is thought to arise from the interplay of two components: the subitizing system which identifies both the number of subgroups and of items within each group, and the possibility to perform basic arithmetic operations on the subitized groups. Here we directly investigate the relative role of these two components in groupitizing via an interference (dual task) paradigm. Participants were required to estimate numerosities of grouped and ungrouped arrays while their attentional resources were fully available (single task) or while performing concurrent tasks loading auditory or visuo-spatial attention (both known to interfere with the subitizing process) as well as while performing arithmetic calculation. The attentional cost of performing any concurrent task was overall higher for grouped than ungrouped stimuli, supporting the idea that groupitizing relies on the recruitment of more than one attention-dependent mechanism. However, depriving visuo-spatial attention and preventing participants from performing calculations caused the strongest decrement in sensory precision for grouped numerosities indicating that these attentional components play a major role in groupitizing. These results are in line with the existence of an estimation mechanism that might operate across all numerical ranges, supplemented by attentional mechanisms (subitizing). This study shows that this attentional-demanding mechanism can be activated also when processing numerosities outside of the subitizing regime (n > 4), provided that grouping cues are available and, in concert with calculation abilities, gives rise to the groupitizing phenomenon. Maldonado Moscoso, P. A., Anobile, G., Maduli, G., Arrighi, R., & Castaldi, E. https://www.pisavisionlab.org/2026/06/12/groupitizing-a-visuo-spatial-and-arithmetic-phenomenon/opmi_a_00181/https://doi.org/10.1162/opmi_a_00181 https://www.pisavisionlab.org/2026/07/08/characterizing-human-disparity-tuning-properties-using-population-receptive-field-mapping/ Wed, 08 Jul 2026 11:50:11 +0000 https://www.pisavisionlab.org/?p=5380 The Journal of Neuroscience Our visual percept of small differences in depth is largely informed by binocular stereopsis, the ability to decode depth from the horizontal offset between the retinal images in each eye. While multiple cortical areas are associated with stereoscopic processing, it is unclear how tuning to specific binocular disparities is organized across the human visual cortex. We used 3 T functional magnetic resonance imaging to generate population receptive fields (pRFs) in response to modulation of binocular disparity to characterize the neural tuning to disparity. We also used psychophysics to measure stereoacuity thresholds compared with backgrounds at different depths (pedestal disparity). Ten human participants (seven females) observed correlated or anticorrelated random-dot stereograms with disparity ranging from −0.3 to 0.3°, and responses were modeled as one-dimensional tuning curves along the depth dimension. First, we demonstrate that lateral and dorsal visual areas show the greatest proportion of vertices selective for binocular disparity. Second, with binocularly correlated stimuli, we show a polynomial relationship between preferred disparity and tuning curve width, with sharply tuned disparity responses at near-zero disparities, and broader disparity tuning profiles at near or far disparities. This relationship held across visual areas and was not present for anticorrelated stimuli. Finally, the individual thresholds for psychophysical stereoacuity at the three different pedestal disparities were broadly related to pRF tuning width in area V1, suggesting a possible limit for fine stereopsis at the earliest level of cortical processing. Together, these findings point to heterogeneity of disparity processing across human visual areas, comparable with nonhuman primates. Ivan Alvarez, Alessandro Mancari, I. Betina Ip, Andrew J. Parker and Holly Bridge https://www.pisavisionlab.org/2026/07/08/characterizing-human-disparity-tuning-properties-using-population-receptive-field-mapping/e0795242025-full/https://doi.org/10.1523/JNEUROSCI.0795-24.2025 https://www.pisavisionlab.org/2026/07/08/receptive-fields-from-single-neuron-recording-and-mri-reveal-similar-information-coding-for-binocular-depth/ Wed, 08 Jul 2026 11:54:42 +0000 https://www.pisavisionlab.org/?p=5383 PNAS The population receptive field (pRF) approach to functional measurement of the sensory properties of magnetic resonance (MR)-identified locations in the human brain was extended to include the third dimension of binocular depth. In total, pRFs were extracted from nine different visual areas (V1, V2, V3, V3AB, V4, V5, V7, Ventral Occipital Cortex: VOC, Lateral Occipital Cortex: LOC) of the human cortex and, where possible, comparisons were made with electrophysiological recordings from homologous areas in the macaque cortex. Human and macaque V1 showed strikingly similar information profiles for the encoding of binocular depth. Further, both human and macaque V5 showed consistent changes in preferred binocular depth of the stimulus, dependent on whether the stimuli were binocularly correlated or anticorrelated. Across the nine areas of the visual cortex explored, the population profiles of pRFs for binocular depth showed evidence of a greater responsiveness to relative depth in higher visual cortical areas, again consistent with the findings from macaque electrophysiology. Overall, the pRF measures of cortical response were more sensitive to fine-scale differences of binocular depth, compared with many existing electrophysiological measures of tuning for binocular depth. Our results show that the pRF method can be extended beyond the characterization of RFs in retinotopic coordinates to reveal higher-order, derived visual properties. The parallels between noninvasive, MR-based measures of pRFs in humans and the electrophysiological recordings of single neurons in experimental animals make a further step toward validation of the pRF methodology. Andrew J. Parker, Ivan Alvarez, Alessandro Mancari, I. Betina Ip, Kristine Krug, and Holly Bridge https://www.pisavisionlab.org/2026/07/08/receptive-fields-from-single-neuron-recording-and-mri-reveal-similar-information-coding-for-binocular-depth/parker-et-al-2025-receptive-fields-from-single-neuron-recording-and-mri-reveal-similar-information-coding-for-binocular/https://doi.org/10.1073/pnas.2409893122 https://www.pisavisionlab.org/2026/07/09/short-term-monocular-deprivation-in-healthy-humans-a-meta-analysis-and-new-perspectives/ Thu, 09 Jul 2026 09:49:21 +0000 https://www.pisavisionlab.org/?p=5389 Royal Society Starting from the early 2010s, several studies have shown that a short period of monocular deprivation in adult volunteers transiently shifts ocular dominance in favour of the deprived eye. We compiled a meta-analysis of 73 such studies and found that the shift of ocular dominance was reliably observed, although with variable effect sizes mainly associated with the duration of deprivation and the technique used for measuring ocular dominance. By contrast, the effect was remarkably stable across experimental designs (translucent versus light-tight patching of the dominant versus non-dominant eye). A qualitatively similar effect was also elicited without deprivation, by distorting the monocular image or making it task irrelevant. These results offer insights into the mechanisms underlying the ocular dominance shift, which we discuss in the light of current models and a new perspective inspired by predictive coding. This line of research allows for a new understanding of the plasticity of early visual processing, which perdures well after the end of developmental critical periods and may be used to promote recovery of visual functions. Cecilia Steinwurzel, Giacomo Pennella, Paola Binda https://www.pisavisionlab.org/2026/07/09/short-term-monocular-deprivation-in-healthy-humans-a-meta-analysis-and-new-perspectives/rspb-2025-2487/https://doi.org/10.1098/rspb.2025.2487