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Di Dona G, Zamfira DA, Battista M, Battaglini L, Perani D, Ronconi L. The role of parietal beta-band activity in the resolution of visual crowding. Neuroimage 2024; 289:120550. [PMID: 38382861 DOI: 10.1016/j.neuroimage.2024.120550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 02/23/2024] Open
Abstract
Visual crowding is the difficulty in identifying an object when surrounded by neighbouring flankers, representing a bottleneck for object perception. Crowding arises not only from the activity of visual areas but also from parietal areas and fronto-parietal network activity. Parietal areas would provide the dorsal-to-ventral guidance for object identification and the fronto-parietal network would modulate the attentional resolution. Several studies highlighted the relevance of beta oscillations (15-25 Hz) in these areas for visual crowding and other connatural visual phenomena. In the present study, we investigated the differential contribution of beta oscillations in the parietal cortex and fronto-parietal network in the resolution of visual crowding. During a crowding task with letter stimuli, high-definition transcranial Alternating Current Stimulation (tACS) in the beta band (18 Hz) was delivered bilaterally on parietal sites, on the right fronto-parietal network, and in a sham regime. Resting-state EEG was recorded before and after stimulation to measure tACS-induced aftereffects. The influence of crowding was reduced only when tACS was delivered bilaterally on parietal sites. In this condition, beta power was reduced after the stimulation. Furthermore, the magnitude of tACS-induced aftereffects varied as a function of individual differences in beta oscillations. Results corroborate the link between parietal beta oscillations and visual crowding, providing fundamental insights on brain rhythms underlying the dorsal-to-ventral guidance in visual perception and suggesting that beta tACS can induce plastic changes in these areas. Remarkably, these findings open new possibilities for neuromodulatory interventions for disorders characterised by abnormal crowding, such as dyslexia.
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Affiliation(s)
- Giuseppe Di Dona
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy.
| | - Denisa Adina Zamfira
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy
| | - Martina Battista
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Piazza S. Francesco 19, 55100 Lucca LU, Italy
| | - Luca Battaglini
- Dipartimento di Psicologia Generale, University of Padova, Via Venezia 8, 35131 Padova PD, Italy
| | - Daniela Perani
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy
| | - Luca Ronconi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy.
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2
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Suzuki K. The effects of positions on deviant processing in mostly incompatible blocks in the flanker task. Psychophysiology 2024; 61:e14509. [PMID: 38149484 DOI: 10.1111/psyp.14509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 11/28/2023] [Accepted: 12/11/2023] [Indexed: 12/28/2023]
Abstract
It is assumed that focused attention is induced by mostly incompatible (MI) blocks in the flanker task. This study aimed to examine the differences in deviant processing between positions of a stimulus in MI blocks. Thirty-nine adults participated in this study. Compatible and incompatible stimuli were classified into three types: typical (central and surrounding colors: black), central-deviant (central: red; surrounding: black), and surrounding-deviant (central: black; surrounding: red). Rare and equiprobable conditions were set for MI blocks. Central- and surrounding-deviant stimuli were presented with low probabilities in the rare condition and with identical probabilities to that of typical stimuli in the equiprobable condition. Deviant processing was evaluated by comparing between event-related potentials in rare and equiprobable conditions. The posterior negativity from 120 to 170 ms (i.e., N1) for central-deviant stimuli was significantly more negative in the rare condition than in the equiprobable condition, whereas there was no difference for surrounding-deviant stimuli. Conversely, the posterior negativity from 180 to 230 ms for both stimuli was significantly more negative in the rare condition than in the equiprobable condition, and the difference (i.e., visual mismatch negativity) was similar in central- and surrounding-deviant stimuli. These findings suggest that focused attention induced by MI blocks leads to differences in deviant processing between central and surrounding areas during the N1 time range. Therefore, evaluations of deviant processing can help examine processing in central and surrounding areas independently and are valuable for understanding cognitive control mechanisms in the flanker tasks.
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Affiliation(s)
- Kota Suzuki
- Faculty of Education, Shitennoji University, Osaka, Japan
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3
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Siman-Tov Z, Lev M, Polat U. Probing the Bottleneck of Awareness Formed by Foveal Crowding: A Neurophysiological Study. Brain Sci 2024; 14:169. [PMID: 38391743 PMCID: PMC10886460 DOI: 10.3390/brainsci14020169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/28/2024] [Accepted: 02/05/2024] [Indexed: 02/24/2024] Open
Abstract
Crowding occurs when an easily identified isolated stimulus is surrounded by stimuli with similar properties, making it very difficult to identify. Crowding is suggested as a mechanism that creates a bottleneck in object recognition and awareness. Recently, we showed that brief presentation times at the fovea resulted in a significant crowding effect on target identification, impaired the target's color awareness, and resulted in a slower reaction time. However, when tagging the target with a red letter, the crowding effect is abolished. Crowding is widely considered a grouping; hence, it is pre-attentive. An event-related potential (ERP) study that investigated the spatial-temporal properties of crowding suggested the involvement of higher-level visual processing. Here, we investigated whether ERP's components may be affected by crowding and tagging, and whether the temporal advantage of ERP can be utilized to gain further information about the crowding mechanism. The participants reported target identification using our standard foveal crowing paradigm. It is assumed that crowding occurs due to a suppressive effect; thus, it can be probed by changes in perceptual (N1, ~160 ms) and attentive (P3 ~300-400 ms) components. We found a suppression effect (less negative ERP magnitude) in N1 under foveal crowding, which was recovered under tagging conditions. ERP's amplitude components (N1 and P3) and the behavioral proportion correct are highly correlated. These findings suggest that crowding is an early grouping mechanism that may be combined with later processing involving the segmentation mechanism.
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Affiliation(s)
- Ziv Siman-Tov
- School of Optometry and Vision Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Maria Lev
- School of Optometry and Vision Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Uri Polat
- School of Optometry and Vision Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
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4
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Moore CM, Zheng Q. Limited midlevel mediation of visual crowding: Surface completion fails to support uncrowding. J Vis 2024; 24:11. [PMID: 38294775 PMCID: PMC10839818 DOI: 10.1167/jov.24.1.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 12/10/2023] [Indexed: 02/01/2024] Open
Abstract
Visual crowding refers to impaired object recognition that is caused by nearby stimuli. It increases with eccentricity. Image-level explanations of crowding maintain that it is caused by information loss within early encoding processes that vary in functionality with eccentricity. Alternative explanations maintain that the interference is not limited to two-dimensional image-level interactions but that it is mediated within representations that reflect three-dimensional scene structure. Uncrowding refers to when adding stimulus information to a display, which increases the noise at an image level, nonetheless decreasing the amount of crowding that occurs. Uncrowding has been interpreted as evidence of midlevel mediation of crowding because the additional information tends to provide an opportunity for perceptually organizing stimuli into distinct and therefore protected representations. It is difficult, however, to rule out image-level explanations of crowding and uncrowding when stimulus differences exist between conditions. We adapted displays of a specific form of uncrowding to minimize stimulus differences across conditions, while retaining the potential for perceptual organization, specifically perceptual surface completion. Uncrowding under these conditions would provide strong support for midlevel mediation of crowding. In five experiments, however, we found no evidence of midlevel mediation of crowding, indicating that at least for this version of uncrowding, image-level explanations cannot be ruled out.
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Affiliation(s)
- Cathleen M Moore
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA
| | - Qingzi Zheng
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA
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5
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Nador J, Reeves A. Crowding expands and is less sensitive to target-flanker differences during a shift of visual attention. Vision Res 2023; 212:108305. [PMID: 37515890 DOI: 10.1016/j.visres.2023.108305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 06/02/2023] [Accepted: 07/20/2023] [Indexed: 07/31/2023]
Abstract
Target-flanker similarity and critical spacing control visual crowding when attention is pre-allocated, but these have not been studied when attention shifts. Flanked target Gabors appeared 8° left and right of central fixation throughout each 1.5 s trial. Subjects reported target Gabor tilt. In Expt. 1, target blinks increased accuracy, and flanker blinks decreased it, but only when attention shifted left or right from a central RSVP cue, hardly before it, indicating an exogenous/endogenous synergy. Whether parallel or orthogonal, flankers of the same wavelength as the target crowded substantially. Parallel half-wavelength flankers also crowded, but orthogonal half-wavelength ones did not. In Expt. 2, crowding when attention shifts was the same for targets and flankers within Bouma's bound (2.5° apart) as outside it (5.0° apart.) In Expt. 3, Bouma's bound was restored when attention was focused continuously on the target. We conclude that crowding temporarily expands and becomes less discriminative when attention shifts.
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Affiliation(s)
- Jeff Nador
- Dept. of Psychology, Northeastern University, 360 Huntingdon Ave., Boston, MA 02115, USA; Dept. of Psychology, Université de Fribourg, Faucigny 2, 1700 Fribourg, Switzerland.
| | - Adam Reeves
- Dept. of Psychology, Northeastern University, 360 Huntingdon Ave., Boston, MA 02115, USA.
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Kim T, Pasupathy A. Neural correlates of crowding in macaque area V4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562617. [PMID: 37905025 PMCID: PMC10614871 DOI: 10.1101/2023.10.16.562617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Visual crowding refers to the phenomenon where a target object that is easily identifiable in isolation becomes difficult to recognize when surrounded by other stimuli (distractors). Extensive psychophysical studies support two alternative possibilities for the underlying mechanisms. One hypothesis suggests that crowding results from the loss of visual information due to pooled encoding of multiple nearby stimuli in the mid-level processing stages along the ventral visual pathway. Alternatively, crowding may arise from limited resolution in decoding object information during recognition and the encoded information may remain inaccessible unless it is salient. To rigorously test these alternatives, we studied the responses of single neurons in macaque area V4, an intermediate stage of the ventral, object-processing pathway, to parametrically designed crowded displays and their texture-statistics matched metameric counterparts. Our investigations reveal striking parallels between how crowding parameters, e.g., number, distance, and position of distractors, influence human psychophysical performance and V4 shape selectivity. Importantly, we found that enhancing the salience of a target stimulus could reverse crowding effects even in highly cluttered scenes and such reversals could be protracted reflecting a dynamical process. Overall, we conclude that a pooled encoding of nearby stimuli cannot explain the observed responses and we propose an alternative model where V4 neurons preferentially encode salient stimuli in crowded displays.
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Affiliation(s)
- Taekjun Kim
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
| | - Anitha Pasupathy
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
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7
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The effects of distractors on brightness perception based on a spiking network. Sci Rep 2023; 13:1517. [PMID: 36707550 PMCID: PMC9883501 DOI: 10.1038/s41598-023-28326-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 01/17/2023] [Indexed: 01/28/2023] Open
Abstract
Visual perception can be modified by the surrounding context. Particularly, experimental observations have demonstrated that visual perception and primary visual cortical responses could be modified by properties of surrounding distractors. However, the underlying mechanism remains unclear. To simulate primary visual cortical activities in this paper, we design a k-winner-take-all (k-WTA) spiking network whose responses are generated through probabilistic inference. In simulations, images with the same target and various surrounding distractors perform as stimuli. Distractors are designed with multiple varying properties, including the luminance, the sizes and the distances to the target. Simulations for each varying property are performed with other properties fixed. Each property could modify second-layer neural responses and interactions in the network. To the same target in the designed images, the modified network responses could simulate distinguishing brightness perception consistent with experimental observations. Our model provides a possible explanation of how the surrounding distractors modify primary visual cortical responses to induce various brightness perception of the given target.
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Biles MK, Maniglia M, Yadav IS, Vice JE, Visscher KM. Training With Simulated Scotoma Leads to Behavioral Improvements Through at Least Two Distinct Mechanisms. Invest Ophthalmol Vis Sci 2023; 64:14. [PMID: 36656567 PMCID: PMC9872837 DOI: 10.1167/iovs.64.1.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/22/2022] [Indexed: 01/20/2023] Open
Abstract
Purpose Individuals with central vision loss due to macular degeneration (MD) often spontaneously develop a preferred retinal locus (PRL) outside the area of retinal damage, which they use instead of the fovea. Those who develop a stable PRL are more successful at coping with their vision loss. However, it is unclear whether improvements in visual performance at the PRL are specific to that retinal location or are also observed in other parts of the retina. Perceptual learning literature suggests that the retinal specificity of these effects provides insight about the mechanisms involved. Better understanding of these mechanisms is necessary for the next generation of interventions and improved patient outcomes. Methods To address this, we trained participants with healthy vision to develop a trained retinal locus (TRL), analogous to the PRL in patients. We trained 24 participants on a visual search task using a gaze-contingent display to simulate a central scotoma. Results Results showed retinotopically specific improvements in visual crowding only at the TRL; however, visual acuity improved in both the TRL and in an untrained retinal locus. Conclusions These results suggest that training with an artificial scotoma involves multiple mechanistic levels, some location-specific and some not, and that simulated scotoma training paradigms likely influence multiple mechanisms simultaneously. Eye movement analysis suggests that the non-retinotopic learning effects may be related to improvements in the capability to maintain a stable gaze during stimulus presentation. This work suggests that effective interventions promoting peripheral viewing may influence multiple mechanisms simultaneously.
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Affiliation(s)
- Mandy K. Biles
- Department of Psychology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Marcello Maniglia
- Department of Psychology, The University of California at Riverside, Riverside, California, United States
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Ishant S. Yadav
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Jason E. Vice
- School of Optometry, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
| | - Kristina M. Visscher
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States
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9
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Henry CA, Kohn A. Feature representation under crowding in macaque V1 and V4 neuronal populations. Curr Biol 2022; 32:5126-5137.e3. [PMID: 36379216 PMCID: PMC9729449 DOI: 10.1016/j.cub.2022.10.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 09/02/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022]
Abstract
Visual perception depends strongly on spatial context. A profound example is visual crowding, whereby the presence of nearby stimuli impairs the discriminability of object features. Despite extensive work on perceptual crowding and the spatial integrative properties of visual cortical neurons, the link between these two aspects of visual processing remains unclear. To understand better the neural basis of crowding, we recorded activity simultaneously from neuronal populations in V1 and V4 of fixating macaque monkeys. We assessed the information available from the measured responses about the orientation of a visual target both for targets presented in isolation and amid distractors. Both single neuron and population responses had less information about target orientation when distractors were present. Information loss was moderate in V1 and more substantial in V4. Information loss could be traced to systematic divisive and additive changes in neuronal tuning. Additive and multiplicative changes in tuning were more severe in V4; in addition, tuning exhibited other, non-affine transformations that were greater in V4, further restricting the ability of a fixed sensory readout strategy to extract accurate feature information across displays. Our results provide a direct test of crowding effects at different stages of the visual hierarchy. They reveal how crowded visual environments alter the spiking activity of cortical populations by which sensory stimuli are encoded and connect these changes to established mechanisms of neuronal spatial integration.
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Affiliation(s)
- Christopher A Henry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Adam Kohn
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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10
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Choung OH, Gordillo D, Roinishvili M, Brand A, Herzog MH, Chkonia E. Intact and deficient contextual processing in schizophrenia patients. Schizophr Res Cogn 2022; 30:100265. [PMID: 36119400 PMCID: PMC9477851 DOI: 10.1016/j.scog.2022.100265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/09/2022] [Accepted: 07/09/2022] [Indexed: 11/25/2022] Open
Abstract
Schizophrenia patients are known to have deficits in contextual vision. However, results are often very mixed. In some paradigms, patients do not take the context into account and, hence, perform more veridically than healthy controls. In other paradigms, context deteriorates performance much more strongly in patients compared to healthy controls. These mixed results may be explained by differences in the paradigms as well as by small or biased samples, given the large heterogeneity of patients' deficits. Here, we show that mixed results may also come from idiosyncrasies of the stimuli used because in variants of the same visual paradigm, tested with the same participants, we found intact and deficient processing.
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Affiliation(s)
- Oh-Hyeon Choung
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Corresponding author. http://lpsy.epfl.ch
| | - Dario Gordillo
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Maya Roinishvili
- Laboratory of Vision Physiology, Ivane Beritashvili Centre of Experimental Biomedicine, Tbilisi, Georgia
- Institute of Cognitive Neurosciences, Free University of Tbilisi, Tbilisi, Georgia
| | - Andreas Brand
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Michael H. Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Eka Chkonia
- Department of Psychiatry, Tbilisi State Medical University, Tbilisi, Georgia
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11
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On letter-specific crowding and reading: Evidence from ERPs. Neuropsychologia 2022; 176:108396. [DOI: 10.1016/j.neuropsychologia.2022.108396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/18/2022]
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12
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Chien SE, Yang YH, Ono Y, Yeh SL. Theta activity in semantic priming under visual crowding as revealed by magnetoencephalography. Neurosci Res 2022; 185:29-39. [PMID: 36113812 DOI: 10.1016/j.neures.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 08/29/2022] [Accepted: 09/11/2022] [Indexed: 11/27/2022]
Abstract
Crowding refers to impaired object recognition of peripheral visual targets caused by nearby flankers. It has been shown that the response to a word was faster when it was preceded by a semantically related than unrelated crowded prime, demonstrating that semantic priming survives crowding. This study examines neural correlates of semantic priming under visual crowding using magnetoencephalography with four conditions: prime (isolated, crowded) x prime-target relationship (related, unrelated). Participants judged whether the target was a word or a nonword. We found significant differences in θ activity at the left inferior frontal gyrus (IFG) for both isolated and crowded primes when comparing the unrelated and related conditions, although the activation was delayed with the crowded prime compared to the isolated prime. The locations within the IFG were also different: theta-band activation was at BA 45 in the isolated condition and at BA 47 in the crowded condition. Phase-locking-value analysis revealed that bilateral IFG was more synchronized with unrelated prime-target pairs than related pairs regardless of whether the primes were isolated or crowded, indicating the recruitment of the right hemisphere when the prime-target semantic relationship was remote. Finally, the distinct waveform patterns found in the isolated and crowded conditions from both the source localization and PLV analysis suggest different neural mechanisms for processing semantic information with isolated primes versus crowded primes.
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Affiliation(s)
- Sung-En Chien
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Yung-Hao Yang
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Yumie Ono
- School of Science and Technology, Meiji University, Kanagawa, Japan
| | - Su-Ling Yeh
- Department of Psychology, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan; Center for Artificial Intelligence and Advanced Robotics, National Taiwan University, Taipei, Taiwan.
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13
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Herzog MH. The Irreducibility of Vision: Gestalt, Crowding and the Fundamentals of Vision. Vision (Basel) 2022; 6:vision6020035. [PMID: 35737422 PMCID: PMC9228288 DOI: 10.3390/vision6020035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/25/2022] [Accepted: 05/31/2022] [Indexed: 11/16/2022] Open
Abstract
What is fundamental in vision has been discussed for millennia. For philosophical realists and the physiological approach to vision, the objects of the outer world are truly given, and failures to perceive objects properly, such as in illusions, are just sporadic misperceptions. The goal is to replace the subjectivity of the mind by careful physiological analyses. Continental philosophy and the Gestaltists are rather skeptical or ignorant about external objects. The percepts themselves are their starting point, because it is hard to deny the truth of one own′s percepts. I will show that, whereas both approaches can well explain many visual phenomena with classic visual stimuli, they both have trouble when stimuli become slightly more complex. I suggest that these failures have a deeper conceptual reason, namely that their foundations (objects, percepts) do not hold true. I propose that only physical states exist in a mind independent manner and that everyday objects, such as bottles and trees, are perceived in a mind-dependent way. The fundamental processing units to process objects are extended windows of unconscious processing, followed by short, discrete conscious percepts.
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Affiliation(s)
- Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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14
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Weiss B, Nárai Á, Vidnyánszky Z. Lateralization of early orthographic processing during natural reading is impaired in developmental dyslexia. Neuroimage 2022; 258:119383. [PMID: 35709947 DOI: 10.1016/j.neuroimage.2022.119383] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 05/08/2022] [Accepted: 06/12/2022] [Indexed: 01/08/2023] Open
Abstract
Skilled reading requires specialized visual cortical processing of orthographic information and its impairment has been proposed as a potential correlate of compromised reading in dyslexia. However, which stage of orthographic information processing during natural reading is disturbed in dyslexics remains unexplored. Here we addressed this question by simultaneously measuring the eye movements and EEG of dyslexic and control young adults during natural reading. Isolated meaningful sentences were presented at five inter-letter spacing levels spanning the range from minimal to extra-large spacing, and participants were instructed to read the text silently at their own pace. Control participants read faster, performed larger saccades and shorter fixations compared to dyslexics. While reading speed peaked around the default letter spacing, saccade amplitude increased and fixation duration decreased with the increase of letter spacing in both groups. Lateralization of occipito-temporal fixation-related EEG activity (FREA) was found in three consecutive time intervals corresponding to early orthographic processing in control readers. Importantly, the lateralization in the time range of the first negative left occipito-temporal FREA peak was specific for first fixations and exhibited an interaction effect between reading ability and letter spacing. The interaction originated in the significant decrease of FREA lateralization at extra-large compared to default letter spacing in control readers and the lack of lateralization in both letter spacing conditions in the case of dyslexics. These findings suggest that expertise-driven hemispheric functional specialization for early orthographic processing thought to be responsible for letter identity extraction during natural reading is compromised in dyslexia.
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Affiliation(s)
- Béla Weiss
- Brain Imaging Centre, Research Centre for Natural Sciences, Magyar tudósok körútja 2., Budapest H-1117, Hungary.
| | - Ádám Nárai
- Brain Imaging Centre, Research Centre for Natural Sciences, Magyar tudósok körútja 2., Budapest H-1117, Hungary
| | - Zoltán Vidnyánszky
- Brain Imaging Centre, Research Centre for Natural Sciences, Magyar tudósok körútja 2., Budapest H-1117, Hungary.
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15
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Shamsi F, Liu R, Kwon M. Binocularly Asymmetric Crowding in Glaucoma and a Lack of Binocular Summation in Crowding. Invest Ophthalmol Vis Sci 2022; 63:36. [PMID: 35084432 PMCID: PMC8802025 DOI: 10.1167/iovs.63.1.36] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Glaucoma is associated with progressive loss of retinal ganglion cells. Here we investigated the impact of glaucomatous damage on monocular and binocular crowding in parafoveal vision. We also examined the binocular summation of crowding to see if crowding is alleviated under binocular viewing. Methods The study design included 40 individuals with glaucoma and 24 age-similar normal cohorts. For each subject, the magnitude of crowding was determined by the extent of crowding zone. Crowding zone measurements were made binocularly in parafoveal vision (i.e., at 2° and 4° retinal eccentricities) visual field. For a subgroup of glaucoma subjects (n = 17), crowding zone was also measured monocularly for each eye. Results Our results showed that, compared with normal cohorts, individuals with glaucoma exhibited significantly larger crowding—enlargement of crowding zone (an increase by 21%; P < 0.01). Moreover, we also observed a lack of binocular summation (i.e., a binocular ratio of 1): binocular crowding was determined by the better eye. Hence, our results did not provide evidence supporting binocular summation of crowding in glaucomatous vision. Conclusions Our findings show that crowding is exacerbated in parafoveal vision in glaucoma and binocularly asymmetric glaucoma seems to induce binocularly asymmetric crowding. Furthermore, the lack of binocular summation for crowding observed in glaucomatous vision combined with the lack of binocular summation reported in a previous study on normal healthy vision support the view that crowding may start in the early stages of visual processing, at least before the process of binocular integration takes place.
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Affiliation(s)
- Foroogh Shamsi
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States
| | - Rong Liu
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States.,Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Department of Life Science and Medicine, University of Science and Technology of China, Hefei, China
| | - MiYoung Kwon
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States.,Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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16
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Balke J, Rolke B, Seibold VC. Temporal preparation accelerates spatial selection by facilitating bottom-up processing. Brain Res 2021; 1777:147765. [PMID: 34951971 DOI: 10.1016/j.brainres.2021.147765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/19/2021] [Accepted: 12/17/2021] [Indexed: 11/02/2022]
Abstract
Temporal preparation facilitates spatial selection in visual search. This selection benefit has not only been observed for targets, but also for task-irrelevant, salient distractors. This result suggests that temporal preparation influences bottom-up salience in spatial selection. To test this assumption, we conducted an event-related-potential (ERP) study in which we measured the joint effect of temporal preparation and target salience on the N2pc as an index of spatial selection and the N1 as an index of perceptual discrimination. To manipulate target salience, we employed two different setsizes (i.e., a small or large number of homogeneous distractors). To manipulate temporal preparation, we presented a warning signal before the search display and we varied the length of the interval (foreperiod) between warning signal and search display in different blocks of trials (constant foreperiod paradigm). Replicating previous results, we observed that the N1 and the N2pc arose earlier in case of good temporal preparation. Importantly, the beneficial effect on the N2pc onset latency was stronger when the target salience was initially low (i.e., small setsize). This result provides evidence that temporal preparation influences bottom-up processing and, thereby, facilitates spatial selection.
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Affiliation(s)
- Janina Balke
- Evolutionary Cognition, Department of Psychology, University of Tuebingen, Schleichstraße 4, 72076 Tuebingen, Germany.
| | - Bettina Rolke
- Evolutionary Cognition, Department of Psychology, University of Tuebingen, Schleichstraße 4, 72076 Tuebingen, Germany.
| | - Verena C Seibold
- Evolutionary Cognition, Department of Psychology, University of Tuebingen, Schleichstraße 4, 72076 Tuebingen, Germany.
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17
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Abstract
In crowding, perception of a target deteriorates in the presence of nearby flankers. Surprisingly, perception can be rescued from crowding if additional flankers are added (uncrowding). Uncrowding is a major challenge for all classic models of crowding and vision in general, because the global configuration of the entire stimulus is crucial. However, it is unclear which characteristics of the configuration impact (un)crowding. Here, we systematically dissected flanker configurations and showed that (un)crowding cannot be easily explained by the effects of the sub-parts or low-level features of the stimulus configuration. Our modeling results suggest that (un)crowding requires global processing. These results are well in line with previous studies showing the importance of global aspects in crowding.
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Affiliation(s)
- Oh-Hyeon Choung
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Alban Bornet
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Adrien Doerig
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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18
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Unraveling brain interactions in vision: The example of crowding. Neuroimage 2021; 240:118390. [PMID: 34271157 DOI: 10.1016/j.neuroimage.2021.118390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 11/22/2022] Open
Abstract
Crowding, the impairment of target discrimination in clutter, is the standard situation in vision. Traditionally, crowding is explained with (feedforward) models, in which only neighboring elements interact, leading to a "bottleneck" at the earliest stages of vision. It is with this implicit prior that most functional magnetic resonance imaging (fMRI) studies approach the identification of the "neural locus" of crowding, searching for the earliest visual area in which the blood-oxygenation-level-dependent (BOLD) signal is suppressed under crowded conditions. Using this classic approach, we replicated previous findings of crowding-related BOLD suppression starting in V2 and increasing up the visual hierarchy. Surprisingly, under conditions of uncrowding, in which adding flankers improves performance, the BOLD signal was further suppressed. This suggests an important role for top-down connections, which is in line with global models of crowding. To discriminate between various possible models, we used dynamic causal modeling (DCM). We show that recurrent interactions between all visual areas, including higher-level areas like V4 and the lateral occipital complex (LOC), are crucial in crowding and uncrowding. Our results explain the discrepancies in previous findings: in a recurrent visual hierarchy, the crowding effect can theoretically be detected at any stage. Beyond crowding, we demonstrate the need for models like DCM to understand the complex recurrent processing which most likely underlies human perception in general.
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19
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Abstract
Visual clutter affects our ability to see. Objects that would be identifiable on their own may become unrecognizable when presented close together ("crowding"), but the psychophysical characteristics of crowding have resisted simplification. Image properties initially thought to produce crowding have paradoxically yielded unexpected results; for example, adding flanking objects can ameliorate crowding (Manassi, Sayim, & Herzog, 2012; Herzog, Sayim, Chcherov, & Manassi, 2015; Pachai, Doerig, & Herzog, 2016). The resulting theory revisions have been sufficiently complex and specialized as to make it difficult to discern what principles may underlie the observed phenomena. Here, a generalized formulation of simple visual contrast energy is presented, arising from straightforward analyses of center and surround neurons in the early visual stream. Extant contrast measures, such as root mean square contrast, are easily shown to fall out as reduced special cases. The new generalized contrast energy metric surprisingly predicts the principal findings of a broad range of crowding studies. These early crowding phenomena may thus be said to arise predominantly from contrast or are, at least, severely confounded by contrast effects. Note that these findings may be distinct from accounts of other, likely downstream, "configural" or "semantic" instances of crowding, suggesting at least two separate forms of crowding that may resist unification. The new fundamental contrast energy formulation provides a candidate explanatory framework that addresses multiple psychophysical phenomena beyond crowding.
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Affiliation(s)
- Antonio Rodriguez
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA
| | - Richard Granger
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA
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20
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Ronconi L, Vitale A, Federici A, Pini E, Molteni M, Casartelli L. Altered neural oscillations and connectivity in the beta band underlie detail-oriented visual processing in autism. Neuroimage Clin 2020; 28:102484. [PMID: 33395975 PMCID: PMC7663221 DOI: 10.1016/j.nicl.2020.102484] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/11/2020] [Accepted: 10/22/2020] [Indexed: 11/21/2022]
Abstract
Sensory and perceptual anomalies may have a major impact on basic cognitive and social skills in humans. Autism Spectrum Disorder (ASD) represents a special perspective to explore this relationship, being characterized by both these features. The present study employed electroencephalography (EEG) to test whether detail-oriented visual perception, a recognized hallmark of ASD, is associated with altered neural oscillations and functional connectivity in the beta frequency band, considering its role in feedback and top-down reentrant signalling in the typical population. Using a visual crowding task, where participants had to discriminate a peripheral target letter surrounded by flankers at different distances, we found that detail-oriented processing in children with ASD, as compared to typically developing peers, could be attributed to anomalous oscillatory activity in the beta band (15-30 Hz), while no differences emerged in the alpha band (8-12 Hz). Altered beta oscillatory response reflected in turn atypical functional connectivity between occipital areas, where the initial stimulus analysis is accomplished, and infero-temporal regions, where objects identity is extracted. Such atypical beta connectivity predicted both ASD symptomatology and their detail-oriented processing. Overall, these results might be explained by an altered feedback connectivity within the visual system, with potential cascade effects in visual scene parsing and higher order functions.
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Affiliation(s)
- Luca Ronconi
- Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy; IRCCS San Raffaele Scientific Institute, Milan, Italy; Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy.
| | - Andrea Vitale
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Alessandra Federici
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy; IMT School of Advanced Studies Lucca, Lucca, Italy
| | - Elisa Pini
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy; Department of Psychology, University of Milano-Bicocca, Milano, Italy
| | - Massimo Molteni
- Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy.
| | - Luca Casartelli
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
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21
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Malania M, Pawellek M, Plank T, Greenlee MW. Training-Induced Changes in Radial-Tangential Anisotropy of Visual Crowding. Transl Vis Sci Technol 2020; 9:25. [PMID: 32879781 PMCID: PMC7442869 DOI: 10.1167/tvst.9.9.25] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 07/08/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose One of the diagnostic features of visual crowding, radial–tangential anisotropy, has been observed both in behavioral experiments as well as in responses of the blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signal. As has been shown previously, crowding is stronger for radially arranged flankers, and this tendency is reflected in BOLD signal suppression. In the current study, we examined the effect of practice on the neural correlates of crowding. We expected that training on a crowding task would cause shrinkage of the crowding zone that would be mirrored in corresponding BOLD signal responses. Methods Pre- and post-training fMRI images were acquired in 17 healthy volunteers using a 3-tesla MRI scanner. Participants were trained over 4 consecutive days on a crowding task. Results Comparison of the pre- and post-training behavioral data indicates a significant shrinkage of the crowding zone as a result of training. Moreover, we observed a pronounced radial–tangential anisotropy in the BOLD signal prior to training; that is, radial flankers induced a larger reduction in the BOLD signal compared to equally spaced tangential flankers. After training, this radial–tangential anisotropy in the BOLD signal was significantly reduced. Specifically, we found significant changes in BOLD responses for the radial flanker configuration. Conclusions Our results demonstrate that training-induced changes in the anisotropic shape of the crowding zone are reflected in the BOLD signal in the early visual cortex. Translational Relevance Perceptual learning tasks may have the potential to improve visual performance by promoting neural plasticity. Our results could motivate the development of suitable rehabilitation protocols for patients with central vision loss.
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Affiliation(s)
- Maka Malania
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Maja Pawellek
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany.,Children's University Hospital, University of Regensburg, Regensburg, Germany
| | - Tina Plank
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Mark W Greenlee
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
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22
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Atilgan N, Yu SM, He S. Visual crowding effect in the parvocellular and magnocellular visual pathways. J Vis 2020; 20:6. [PMID: 32749447 PMCID: PMC7438633 DOI: 10.1167/jov.20.8.6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The crowding effect, defined as the detrimental effects of nearby items on visual object recognition, has been extensively investigated. Previous studies have primarily focused on finding the stage(s) in the visual hierarchy where crowding starts to limit target processing, while little attention has been focused on potential differences between the parvocellular (P) and magnocellular (M) pathways in crowding mechanisms. Here, we investigated the crowding effect in these parallel visual pathways. InExperiment 1, stimuli were designed to separately engage the P or M pathway, by tuning stimulus and background features (e.g., temporal frequency and color) to activate the targeted pathway and saturate the other pathway, respectively. Results showed that at the same eccentricity and with the same tasks, targets processed in the M pathway appeared to be more vulnerable to crowding effect. InExperiment 2, crowding effects were studied using three different types of stimuli and visual tasks (form, color, and motion), presumably with different degrees of dependence on the P and M pathways. Results revealed that color, motion, and form discrimination were increasingly more affected by crowding. We conclude that processing in the M and P pathways are differentially impacted by crowding; and importantly, crowding seems to affect processing of spatial forms more than other stimulus properties.
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23
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Abstract
To extract meaningful information from scenes, the visual system must combine local cues that can vary greatly in their degree of reliability. Here, we asked whether cue reliability mostly affects visual or decision-related processes, using visual evoked potentials (VEPs) and a model-based approach to identify when and where stimulus-evoked brain activity reflects cue reliability. Participants performed a shape discrimination task on Gaborized ellipses, while we parametrically and independently, varied the reliability of contour or surface cues. We modeled the expected behavioral performance as a linear function of cue reliability and established at what latencies and electrodes VEP activity reflected behavioral sensitivity to cue reliability. We found that VEPs were linearly related to the individual behavioral predictors at around 400 ms post-stimulus, at electrodes over parietal and lateral temporal cortex. The observed cue reliability effects were similar for variations in contour and surface cues. Notably, effects of cue reliability were absent at earlier latencies where visual shape information is typically reported, and also in data time-locked to the behavioral response, suggesting the effects are not decision-related. These results indicate that reliability of visual cues is reflected in late distributed perceptual processes.
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Affiliation(s)
- Giovanni Mancuso
- Perceptual Networks Group, Department of Psychology, University of Fribourg, Fribourg, Switzerland
| | - Gijs Plomp
- Perceptual Networks Group, Department of Psychology, University of Fribourg, Fribourg, Switzerland
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24
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Roumani D, Moutoussis K. Invisible Adaptation: The Effect of Awareness on the Strength of the Motion Aftereffect. Perception 2020; 49:835-857. [PMID: 32605425 DOI: 10.1177/0301006620936853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The ability to process information despite the lack of perceptual awareness is one of the most fascinating aspects of the visual system. Such unconscious processing is often investigated using adaptation, where any presence of the former can be traced by its footprint on aftereffects following the latter. We have investigated the mechanisms of the motion aftereffect (MAE) using random dot displays of varying motion coherence as well as crowding to modulate both the physical as well as the perceptual strength of the adaptation stimulus. Perceptual strength was quantitatively measured as the performance in a forced-choice direction-discrimination task. A motion-nulling technique was used to quantitatively measure the strength of the MAE. We show that the strength of the dynamic MAE is independently influenced by both the physical stimulus strength as well as the subjective perceptual strength, with the effect of the former being more prominent than that of the latter. We further show that the MAE still persists under conditions of subthreshold perception. Our results suggest that perceptual awareness can influence the strength of visual processing, but the latter is not fully dependent on the former and can still take place at its partial or even total absence.
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Affiliation(s)
- Daphne Roumani
- Cognitive Science Division, Department of Philosophy and History of Science, National and Kapodistrian University of Athens, Greece
| | - Konstantinos Moutoussis
- Cognitive Science Division, Department of Philosophy and History of Science, National and Kapodistrian University of Athens, Greece
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25
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Bonacci LM, Bressler S, Kwasa JAC, Noyce AL, Shinn-Cunningham BG. Effects of Visual Scene Complexity on Neural Signatures of Spatial Attention. Front Hum Neurosci 2020; 14:91. [PMID: 32265675 PMCID: PMC7105597 DOI: 10.3389/fnhum.2020.00091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/02/2020] [Indexed: 11/28/2022] Open
Abstract
Spatial selective attention greatly affects our processing of complex visual scenes, yet the way in which the brain selects relevant objects while suppressing irrelevant objects is still unclear. Evidence of these processes has been found using non-invasive electroencephalography (EEG). However, few studies have characterized these measures during attention to dynamic stimuli, and little is known regarding how these measures change with increased scene complexity. Here, we compared attentional modulation of the EEG N1 and alpha power (oscillations between 8–14 Hz) across three visual selective attention tasks. The tasks differed in the number of irrelevant stimuli presented, but all required sustained attention to the orientation trajectory of a lateralized stimulus. In scenes with few irrelevant stimuli, top-down control of spatial attention is associated with strong modulation of both the N1 and alpha power across parietal-occipital channels. In scenes with many irrelevant stimuli in both hemifields, however, top-down control is no longer represented by strong modulation of alpha power, and N1 amplitudes are overall weaker. These results suggest that as a scene becomes more complex, requiring suppression in both hemifields, the neural signatures of top-down control degrade, likely reflecting some limitation in EEG to represent this suppression.
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Affiliation(s)
- Lia M Bonacci
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Scott Bressler
- Graduate Program in Neuroscience, Boston University, Boston, MA, United States
| | - Jasmine A C Kwasa
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Abigail L Noyce
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA, United States
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26
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Henry CA, Kohn A. Spatial contextual effects in primary visual cortex limit feature representation under crowding. Nat Commun 2020; 11:1687. [PMID: 32245941 PMCID: PMC7125172 DOI: 10.1038/s41467-020-15386-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 03/09/2020] [Indexed: 12/25/2022] Open
Abstract
Crowding is a profound loss of discriminability of visual features, when a target stimulus is surrounded by distractors. Numerous studies of human perception have characterized how crowding depends on the properties of a visual display. Yet, there is limited understanding of how and where stimulus information is lost in the visual system under crowding. Here, we show that macaque monkeys exhibit perceptual crowding for target orientation that is similar to humans. We then record from neuronal populations in monkey primary visual cortex (V1). These populations show an appreciable loss of information about target orientation in the presence of distractors, due both to divisive and additive modulation of responses to targets by distractors. Our results show that spatial contextual effects in V1 limit the discriminability of visual features and can contribute substantively to crowding. Visual crowding can strongly limit perceptual discriminability, yet its neural basis remains unclear. Here, the authors show that perceptual crowding is similar in monkeys and humans, and that feature encoding in neuronal populations in primary visual cortex is limited for displays inducing crowding.
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Affiliation(s)
- Christopher A Henry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Adam Kohn
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.,Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.,Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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27
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Battaglini L, Ghiani A, Casco C, Ronconi L. Parietal tACS at beta frequency improves vision in a crowding regime. Neuroimage 2019; 208:116451. [PMID: 31821867 DOI: 10.1016/j.neuroimage.2019.116451] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/22/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022] Open
Abstract
Visual crowding is the inability to discriminate objects when presented with nearby flankers and sets a fundamental limit for conscious perception. Beta oscillations in the parietal cortex were found to be associated to crowding, with higher beta amplitude related to better crowding resilience. An open question is whether beta activity directly and selectively modulates crowding. We employed Transcranial Alternating Current Stimulation (tACS) in the beta band (18-Hz), in the alpha band (10-Hz) or in a sham regime, asking whether 18-Hz tACS would selectively improve the perception of crowded stimuli by increasing parietal beta activity. Resting-state electroencephalography (EEG) was measured before and after stimulation to test the influence of tACS on endogenous oscillations. Consistently with our predictions, we found that 18-Hz tACS, as compared to 10-Hz tACS and sham stimulation, reduced crowding. This improvement was found specifically in the contralateral visual hemifield and was accompanied by an increased amplitude of EEG beta oscillations, confirming an effect on endogenous brain rhythms. These results support a causal relationship between parietal beta oscillations and visual crowding and provide new insights into the precise oscillatory mechanisms involved in human vision.
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Affiliation(s)
- Luca Battaglini
- Department of General Psychology, University of Padova, Italy; Neuro.Vis.U.S. Laboratory, University of Padova, Padova, Italy
| | - Andrea Ghiani
- Department of General Psychology, University of Padova, Italy
| | - Clara Casco
- Department of General Psychology, University of Padova, Italy; Neuro.Vis.U.S. Laboratory, University of Padova, Padova, Italy
| | - Luca Ronconi
- Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.
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28
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The Critical Role of V2 Population Receptive Fields in Visual Orientation Crowding. Curr Biol 2019; 29:2229-2236.e3. [DOI: 10.1016/j.cub.2019.05.068] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 03/26/2019] [Accepted: 05/28/2019] [Indexed: 11/20/2022]
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29
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Bertoni S, Franceschini S, Ronconi L, Gori S, Facoetti A. Is excessive visual crowding causally linked to developmental dyslexia? Neuropsychologia 2019; 130:107-117. [PMID: 31077708 DOI: 10.1016/j.neuropsychologia.2019.04.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/15/2019] [Accepted: 04/24/2019] [Indexed: 11/17/2022]
Abstract
For about 10% of children reading acquisition is extremely difficult because they are affected by a heritable neurobiological disorder called developmental dyslexia (DD), mainly associated to an auditory-phonological disorder. Visual crowding is a universal phenomenon that impairs the recognition of stimuli in clutter, such as a letter in a word or a word in a text. Several studies have shown an excessive crowding in individuals with DD, but the causal link between excessive crowding and DD is not yet clearly established. An excessive crowding might be, indeed, a simple effect of DD due to reduced reading experience. The results of five experiments in 181 children reveal that: (i) an excessive crowding only at unattended locations characterizes an unselected group of children with DD (Experiment 1); (ii) an extra-large spaced text increases reading accuracy by reducing crowding in an unselected group of children with DD (Experiment 2); (iii) efficient attentional action video game trainings reduce crowding and accelerate reading speed in two unselected groups of children with DD (Experiment 3 and 4), and; (iv) pre-reading crowding longitudinally predicts future poor readers (Experiment 5). Our results show multiple causal links between visual crowding and learning to read. These findings provide new insights for a more efficient remediation and prevention for DD.
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Affiliation(s)
- Sara Bertoni
- Developmental and Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, Padova 35131, Italy.
| | - Sandro Franceschini
- Developmental and Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, Padova 35131, Italy.
| | - Luca Ronconi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto 38068, Italy; Child Psychopathology Unit, Scientific Institute "E. Medea", Bosisio Parini, Lecco 23842, Italy
| | - Simone Gori
- Department of Human and Social Sciences, University of Bergamo, Bergamo 24129, Italy
| | - Andrea Facoetti
- Developmental and Cognitive Neuroscience Lab, Department of General Psychology, University of Padua, Padova 35131, Italy
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30
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Schallmo MP, Kale AM, Murray SO. The time course of different surround suppression mechanisms. J Vis 2019; 19:12. [PMID: 30952163 PMCID: PMC6464404 DOI: 10.1167/19.4.12] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 01/08/2019] [Indexed: 11/24/2022] Open
Abstract
What we see depends on the spatial context in which it appears. Previous work has linked the suppression of perceived contrast by surrounding stimuli to reduced neural responses in early visual cortex. This surround suppression depends on at least two separable neural mechanisms, "low-level" and "higher level," which can be differentiated by their response characteristics. We used electroencephalography to demonstrate for the first time that human occipital neural responses show evidence of these two suppression mechanisms. Eighteen adults (10 women, 8 men) each participated in three experimental sessions, in which they viewed visual stimuli through a mirror stereoscope. The first session was used to identify the C1 component, while the second and third comprised the main experiment. Event-related potentials were measured in response to center gratings either with no surround or with surrounding gratings oriented parallel or orthogonal, and presented in either the same eye (monoptic) or the opposite eye (dichoptic). We found that the earliest component of an event-related potential (C1; ∼60 ms) was suppressed by surrounding stimuli, but that suppression did not depend on surround configuration. This suggests a suppression mechanism that is not tuned for relative orientation acting on the earliest cortical response to the target. A later response component (N1; ∼160 ms) showed stronger suppression for parallel and monoptic surrounds, consistent with our earlier psychophysical results and a second form of suppression that is binocular and orientation tuned. We conclude that these two forms of surround suppression have distinct response time courses in the human visual system, which can be differentiated using electrophysiology.
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Affiliation(s)
- Michael-Paul Schallmo
- Department of Psychology, University of Washington, Seattle, WA, USA
- Department of Psychiatry and Behavioral Science, University of Minnesota, Minneapolis, MN, USA
| | - Alex M Kale
- Department of Psychology, University of Washington, Seattle, WA, USA
| | - Scott O Murray
- Department of Psychology, University of Washington, Seattle, WA, USA
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31
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Han Q, Luo H. Visual crowding involves delayed frontoparietal response and enhanced top-down modulation. Eur J Neurosci 2019; 50:2931-2941. [PMID: 30864167 DOI: 10.1111/ejn.14401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/15/2019] [Accepted: 03/05/2019] [Indexed: 11/26/2022]
Abstract
Crowding, the disrupted recognition of a peripheral target in the presence of nearby flankers, sets a fundamental limit on peripheral vision perception. Debates persist on whether the limit occurs at early visual cortices or is induced by top-down modulation, leaving the neural mechanism for visual crowding largely unclear. To resolve the debate, it is crucial to extract the neural signals elicited by the target from that by the target-flanker clutter, with high temporal resolution. To achieve this purpose, here we employed a temporal response function (TRF) approach to dissociate target-specific response from the overall electroencephalograph (EEG) recordings when the target was presented with (crowded) or without flankers (uncrowded) while subjects were performing a discrimination task on the peripherally presented target. Our results demonstrated two components in the target-specific contrast-tracking TRF response-an early component (100-170 ms) in occipital channels and a late component (210-450 ms) in frontoparietal channels. The late frontoparietal component, which was delayed in time under the crowded condition, was correlated with target discrimination performance, suggesting its involvement in visual crowding. Granger causality analysis further revealed stronger top-down modulation on the target stimulus under the crowded condition. Taken together, our findings support that crowding is associated with a top-down process which modulates the low-level sensory processing and delays the behavioral-relevant response in the high-level region.
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Affiliation(s)
- Qiming Han
- School of Psychological and Cognitive Sciences, Peking University, Beijing, China.,IDG/McGovern Institute for Brain Research, Peking University, Beijing, China.,Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Huan Luo
- School of Psychological and Cognitive Sciences, Peking University, Beijing, China.,IDG/McGovern Institute for Brain Research, Peking University, Beijing, China.,Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
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32
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Contemori G, Trotter Y, Cottereau BR, Maniglia M. tRNS boosts perceptual learning in peripheral vision. Neuropsychologia 2019; 125:129-136. [DOI: 10.1016/j.neuropsychologia.2019.02.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 01/30/2019] [Accepted: 02/01/2019] [Indexed: 01/04/2023]
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33
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Linkage between retinal ganglion cell density and the nonuniform spatial integration across the visual field. Proc Natl Acad Sci U S A 2019; 116:3827-3836. [PMID: 30737290 PMCID: PMC6397585 DOI: 10.1073/pnas.1817076116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The integration of visual information over space is critical to human pattern vision. For either luminance detection or object recognition, the position of the target in the visual field governs the size of a window within which visual information is integrated. Here we analyze the relationship between the topographic distribution of ganglion cell density and the nonuniform spatial integration across the visual field. We find that the variation in the retinal ganglion cell (RGC) density across the human retina is closely matched to the variation in the extent of spatial integration. Our study suggests that a fixed number of RGCs subserves spatial integration of visual input, independent of the visual-field location. The ability to integrate visual information over space is a fundamental component of human pattern vision. Regardless of whether it is for detecting luminance contrast or for recognizing objects in a cluttered scene, the position of the target in the visual field governs the size of a window within which visual information is integrated. Here we analyze the relationship between the topographic distribution of ganglion cell density and the nonuniform spatial integration across the visual field. The extent of spatial integration for luminance detection (Ricco’s area) and object recognition (crowding zone) are measured at various target locations. The number of retinal ganglion cells (RGCs) underlying Ricco’s area or crowding zone is estimated by computing the product of Ricco’s area (or crowding zone) and RGC density for a given target location. We find a quantitative agreement between the behavioral data and the RGC density: The variation in the sampling density of RGCs across the human retina is closely matched to the variation in the extent of spatial integration required for either luminance detection or object recognition. Our empirical data combined with the simulation results of computational models suggest that a fixed number of RGCs subserves spatial integration of visual input, independent of the visual-field location.
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34
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Chakravarthi R, Herbert A. Two's company, three's a crowd: Individuation is necessary for object recognition. Cognition 2018; 184:69-82. [PMID: 30576886 DOI: 10.1016/j.cognition.2018.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 11/30/2022]
Abstract
Object recognition is essential for navigating the real world. Despite decades of research on this topic, the processing steps necessary for recognition remain unclear. In this study, we examined the necessity and role of individuation, the ability to select a small number of spatially distinct objects irrespective of their identity, in the recognition process. More specifically, we tested if the ability to rapidly individuate and enumerate a small number of objects (subitizing) can be impaired by crowding. Crowding is flanker-induced interference that specifically impedes the recognition process. We found that subitizing is impaired when objects are close to each other (Experiment 1), and if the target objects are surrounded by irrelevant but perceptually similar flankers (Experiments 2-4). This impairment cannot be attributed to confusion between targets and flankers, wherein flankers are inadvertently included in or targets are excluded from enumeration (Experiments 3-4). Importantly, the flanker induced interference was comparable in both subitizing and crowding tasks (Experiment 4), suggesting that individuation and identification share a common processing pathway. We conclude that individuation is an essential stage in the object recognition pipeline and argue for a cohesive proposal that both crowding and subitizing are due to limitations of selective attention.
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Affiliation(s)
| | - Amy Herbert
- School of Psychology, University of Aberdeen, Kings College, Aberdeen AB24 3FX, UK
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35
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Peng C, Hu C, Chen Y. The Temporal Dynamic Relationship Between Attention and Crowding: Electrophysiological Evidence From an Event-Related Potential Study. Front Neurosci 2018; 12:844. [PMID: 30524226 PMCID: PMC6261982 DOI: 10.3389/fnins.2018.00844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 10/29/2018] [Indexed: 11/13/2022] Open
Abstract
Visual crowding is the difficulty experienced in identifying a target flanked by other objects within the peripheral visual field. Despite extensive research conducted on this topic, the precise relationship between attention and crowding is still debatable. One perspective suggests that crowding is a bottom-up and pre-attentive process, while another suggests that crowding is top-down and attentional. A third perspective proposes that crowding is a combination of bottom-up and top-down processes. To address this debate, the current study manipulated the attention and distance between targets and flankers, while simultaneously measuring event-related potentials, in human participants. Results indicated that, compared to uncrowded targets, crowded targets elicited more negative frontal N1 and P2 activity and a less negative occipital N1 activity, regardless of whether targets were attended or unattended, and a more positive occipital P2 activity when they were attended. Furthermore, the crowded minus uncrowded difference amplitude was more negative over the frontal region and more positive over the occipital region when the targets were attended, compared to when they were unattended during the N1 and P2 stages. This suggests that crowding, a concept that originates from Gestalt grouping, occurs automatically and can be modulated by attention.
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Affiliation(s)
- Chunhua Peng
- Laboratory of Emotion and Mental Health, Chongqing University of Arts and Sciences, Chongqing, China
- Collaborative Innovation Center for Brain Science, Chongqing, China
| | - Chunmei Hu
- Laboratory of Emotion and Mental Health, Chongqing University of Arts and Sciences, Chongqing, China
- Collaborative Innovation Center for Brain Science, Chongqing, China
| | - Youguo Chen
- Key Laboratory of Cognition and Personality (Ministry of Education), Center of Studies for Psychology and Social Development, Faculty of Psychology, Southwest University, Chongqing, China
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36
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Schafer A, Rouland JF, Peyrin C, Szaffarczyk S, Boucart M. Glaucoma Affects Viewing Distance for Recognition of Sex and Facial Expression. ACTA ACUST UNITED AC 2018; 59:4921-4928. [DOI: 10.1167/iovs.18-24875] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Audrey Schafer
- Centre Hospitalier Universitaire de Lille, Hôpital Huriez, Service d'Ophtalmologie, Lille, France
| | - Jean François Rouland
- Centre Hospitalier Universitaire de Lille, Hôpital Huriez, Service d'Ophtalmologie, Lille, France
- SCALab, University of Lille, Centre National de la Recherche Scientifique, Lille, France
| | - Carole Peyrin
- University Grenoble Alpes, CNRS, LPNC, 38000 Grenoble, France
| | - Sebastien Szaffarczyk
- SCALab, University of Lille, Centre National de la Recherche Scientifique, Lille, France
| | - Muriel Boucart
- SCALab, University of Lille, Centre National de la Recherche Scientifique, Lille, France
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37
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Kalpadakis-Smith AV, Goffaux V, Greenwood JA. Crowding for faces is determined by visual (not holistic) similarity: Evidence from judgements of eye position. Sci Rep 2018; 8:12556. [PMID: 30135454 PMCID: PMC6105622 DOI: 10.1038/s41598-018-30900-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/01/2018] [Indexed: 11/08/2022] Open
Abstract
Crowding (the disruption of object recognition in clutter) presents the fundamental limitation on peripheral vision. For simple objects, crowding is strong when target/flanker elements are similar and weak when they differ - a selectivity for target-flanker similarity. In contrast, the identification of upright holistically-processed face stimuli is more strongly impaired by upright than inverted flankers, whereas inverted face-targets are impaired by both - a pattern attributed to an additional stage of crowding selective for "holistic similarity" between faces. We propose instead that crowding is selective for target-flanker similarity in all stimuli, but that this selectivity is obscured by task difficulty with inverted face-targets. Using judgements of horizontal eye-position that are minimally affected by inversion, we find that crowding is strong when target-flanker orientations match and weak when they differ for both upright and inverted face-targets. By increasing task difficulty, we show that this selectivity for target-flanker similarity is obscured even for upright face-targets. We further demonstrate that this selectivity follows differences in the spatial order of facial features, rather than "holistic similarity" per se. There is consequently no need to invoke a distinct stage of holistic crowding for faces - crowding is selective for target-flanker similarity, even with complex stimuli such as faces.
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Affiliation(s)
| | - Valérie Goffaux
- Research Institute for Psychological Science, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Institute of Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - John A Greenwood
- Experimental Psychology, University College London, London, United Kingdom
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38
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Strappini F, Galati G, Martelli M, Di Pace E, Pitzalis S. Perceptual integration and attention in human extrastriate cortex. Sci Rep 2017; 7:14848. [PMID: 29093537 PMCID: PMC5665925 DOI: 10.1038/s41598-017-13921-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 10/04/2017] [Indexed: 11/29/2022] Open
Abstract
Visual crowding is a perceptual phenomenon with far-reaching implications in both perceptual (e.g., object recognition and reading) and clinical (e.g., developmental dyslexia and visual agnosia) domains. Here, we combined event-related fMRI measurements and wide-field brain mapping methods to investigate whether the BOLD response evoked by visual crowding is modulated by different attentional conditions. Participants underwent two sessions of psychophysical training outside the scanner, and then fMRI BOLD activity was measured simultaneously in early visual areas (including the visual word form area, VWFA), while they viewed strongly-crowded and weakly-crowded Gabor patches in attended and unattended conditions. We found that crowding increased BOLD activity in a network of areas including V1, V2, V3A, V4/V8, and VWFA. In V4/V8 and VWFA we found an increased activity related to attention. The effect of crowding in V1 was recorded only when attention was fully devoted to the target location. Our results provide evidence that some area beyond V1 might be the likely candidate for the site of crowding, thus supporting the view of visual crowding as a mid-level visual phenomenon.
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Affiliation(s)
- Francesca Strappini
- Neurobiology Department, Weizmann Institute of Science, Rehovot, Israel. .,Department of Psychology, Sapienza University, Rome, Italy. .,Neuropsychology Center, Santa Lucia Foundation, Rome, Italy.
| | - Gaspare Galati
- Department of Psychology, Sapienza University, Rome, Italy.,Neuropsychology Center, Santa Lucia Foundation, Rome, Italy
| | - Marialuisa Martelli
- Department of Psychology, Sapienza University, Rome, Italy.,Neuropsychology Center, Santa Lucia Foundation, Rome, Italy
| | - Enrico Di Pace
- Department of Psychology, Sapienza University, Rome, Italy
| | - Sabrina Pitzalis
- Neuropsychology Center, Santa Lucia Foundation, Rome, Italy.,Department of Education in Sport and Human Movement, University of Rome "Foro Italico", Rome, Italy
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39
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Juxtaposing the real-time unfolding of subjective experience and ERP neuromarker dynamics. Conscious Cogn 2017; 54:3-19. [DOI: 10.1016/j.concog.2017.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 01/08/2023]
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40
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Ronconi L, Bellacosa Marotti R. Awareness in the crowd: Beta power and alpha phase of prestimulus oscillations predict object discrimination in visual crowding. Conscious Cogn 2017; 54:36-46. [DOI: 10.1016/j.concog.2017.04.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 04/26/2017] [Accepted: 04/29/2017] [Indexed: 12/23/2022]
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41
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Electrophysiological correlates of visual backward masking in high schizotypic personality traits participants. Psychiatry Res 2017; 254:251-257. [PMID: 28477548 DOI: 10.1016/j.psychres.2017.04.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 03/17/2017] [Accepted: 04/23/2017] [Indexed: 01/02/2023]
Abstract
Visual backward masking is strongly deteriorated in patients with schizophrenia. Masking deficits are associated with strongly reduced amplitudes of the global field power in the EEG. Healthy participants who scored high in cognitive disorganization (a schizotypic trait) were impaired in backward masking compared to participants who scored low. Here, we show that the global field power is also reduced in healthy participants scoring high (n=25) as compared to low (n=20) in cognitive disorganization, though quantitatively less pronounced than in patients (n=10). These results point to similar mechanisms underlying visual backward masking deficits along the schizophrenia spectrum.
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42
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Variations in crowding, saccadic precision, and spatial localization reveal the shared topology of spatial vision. Proc Natl Acad Sci U S A 2017; 114:E3573-E3582. [PMID: 28396415 DOI: 10.1073/pnas.1615504114] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Visual sensitivity varies across the visual field in several characteristic ways. For example, sensitivity declines sharply in peripheral (vs. foveal) vision and is typically worse in the upper (vs. lower) visual field. These variations can affect processes ranging from acuity and crowding (the deleterious effect of clutter on object recognition) to the precision of saccadic eye movements. Here we examine whether these variations can be attributed to a common source within the visual system. We first compared the size of crowding zones with the precision of saccades using an oriented clock target and two adjacent flanker elements. We report that both saccade precision and crowded-target reports vary idiosyncratically across the visual field with a strong correlation across tasks for all participants. Nevertheless, both group-level and trial-by-trial analyses reveal dissociations that exclude a common representation for the two processes. We therefore compared crowding with two measures of spatial localization: Landolt-C gap resolution and three-dot bisection. Here we observe similar idiosyncratic variations with strong interparticipant correlations across tasks despite considerably finer precision. Hierarchical regression analyses further show that variations in spatial precision account for much of the variation in crowding, including the correlation between crowding and saccades. Altogether, we demonstrate that crowding, spatial localization, and saccadic precision show clear dissociations, indicative of independent spatial representations, whilst nonetheless sharing idiosyncratic variations in spatial topology. We propose that these topological idiosyncrasies are established early in the visual system and inherited throughout later stages to affect a range of higher-level representations.
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43
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Ronconi L, Bertoni S, Bellacosa Marotti R. The neural origins of visual crowding as revealed by event-related potentials and oscillatory dynamics. Cortex 2016; 79:87-98. [DOI: 10.1016/j.cortex.2016.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/20/2015] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
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44
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Yong K, Rajdev K, Warrington E, Nicholas J, Warren J, Crutch S. A longitudinal investigation of the relationship between crowding and reading: A neurodegenerative approach. Neuropsychologia 2016; 85:127-36. [PMID: 26926579 PMCID: PMC4863520 DOI: 10.1016/j.neuropsychologia.2016.02.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 02/23/2016] [Accepted: 02/26/2016] [Indexed: 11/24/2022]
Abstract
We have previously documented two patients (FOL and CLA) with posterior cortical atrophy who achieved accurate and rapid reading despite deficits in ten measures of visual processing, with two notable exceptions: (1) a measure of visual acuity, (2) a measure of visual crowding. Subsequent longitudinal investigation of these patients was carried out, involving annual tests of early visual, visuoperceptual and visuospatial processing and assessment of reading ability. Follow-up assessments identified the evolution of a particular early visual processing deficit, excessive visual crowding; this deficit has been previously implicated in forms of dyslexia. Consistent with the link between crowding and reading dysfunction, follow-up assessments also revealed deterioration in both patients' reading ability. The current findings demonstrate a neurodegenerative approach towards understanding the relationship between visual crowding and the reading system, and suggest possible mechanisms for how excessive crowding may disrupt word recognition.
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Affiliation(s)
- Keir Yong
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, UK.
| | - Kishan Rajdev
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, UK
| | - Elizabeth Warrington
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, UK
| | - Jennifer Nicholas
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, UK
| | - Jason Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, UK
| | - Sebastian Crutch
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, UK
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45
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Coates DR, Chung STL. Crowding in the S-cone pathway. Vision Res 2016; 122:81-92. [PMID: 27063360 DOI: 10.1016/j.visres.2016.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 02/24/2016] [Accepted: 03/14/2016] [Indexed: 10/21/2022]
Abstract
The spatial extent of interference from nearby object or contours (the critical spacing of "crowding") has been thoroughly characterized across the visual field, typically using high contrast achromatic stimuli. However, attempts to link this measure with known properties of physiological pathways have been inconclusive. The S-cone pathway, with its ease of psychophysical isolation and known anatomical characteristics, offers a unique tool to gain additional insights into crowding. In this study, we measured the spatial extent of crowding in the S-cone pathway at several retinal locations using a chromatic adaptation paradigm. S-cone crowding was evident and extensive, but its spatial extent changed less markedly as a function of retinal eccentricity than the extent found using traditional achromatic stimuli. However, the spatial extent agreed with that of low contrast achromatic stimuli matched for isolated resolvability. This suggests that common cortical mechanisms mediate the crowding effect in the S-cone and achromatic pathway, but contrast is an important factor. The low contrast of S-cone stimuli makes S-cone vision more acuity-limited than crowding-limited.
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Affiliation(s)
- Daniel R Coates
- Vision Science Graduate Group, University of California, Berkeley, United States.
| | - Susana T L Chung
- Vision Science Graduate Group, University of California, Berkeley, United States; School of Optometry, University of California, Berkeley, United States
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46
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Early recurrence and ongoing parietal driving during elementary visual processing. Sci Rep 2015; 5:18733. [PMID: 26692466 PMCID: PMC4686934 DOI: 10.1038/srep18733] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 11/25/2015] [Indexed: 11/29/2022] Open
Abstract
Visual stimuli quickly activate a broad network of brain areas that often show reciprocal structural connections between them. Activity at short latencies (<100 ms) is thought to represent a feed-forward activation of widespread cortical areas, but fast activation combined with reciprocal connectivity between areas in principle allows for two-way, recurrent interactions to occur at short latencies after stimulus onset. Here we combined EEG source-imaging and Granger-causal modeling with high temporal resolution to investigate whether recurrent and top-down interactions between visual and attentional brain areas can be identified and distinguished at short latencies in humans. We investigated the directed interactions between widespread occipital, parietal and frontal areas that we localized within participants using fMRI. The connectivity results showed two-way interactions between area MT and V1 already at short latencies. In addition, the results suggested a large role for lateral parietal cortex in coordinating visual activity that may be understood as an ongoing top-down allocation of attentional resources. Our results support the notion that indirect pathways allow early, evoked driving from MT to V1 to highlight spatial locations of motion transients, while influence from parietal areas is continuously exerted around stimulus onset, presumably reflecting task-related attentional processes.
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47
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Herzog MH, Thunell E, Ögmen H. Putting low-level vision into global context: Why vision cannot be reduced to basic circuits. Vision Res 2015; 126:9-18. [PMID: 26456069 DOI: 10.1016/j.visres.2015.09.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 07/28/2015] [Accepted: 09/18/2015] [Indexed: 11/28/2022]
Abstract
To cope with the complexity of vision, most models in neuroscience and computer vision are of hierarchical and feedforward nature. Low-level vision, such as edge and motion detection, is explained by basic low-level neural circuits, whose outputs serve as building blocks for more complex circuits computing higher level features such as shape and entire objects. There is an isomorphism between states of the outer world, neural circuits, and perception, inspired by the positivistic philosophy of the mind. Here, we show that although such an approach is conceptually and mathematically appealing, it fails to explain many phenomena including crowding, visual masking, and non-retinotopic processing.
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Affiliation(s)
- Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
| | - Evelina Thunell
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - Haluk Ögmen
- Department of Electrical and Computer Engineering, Center for Neuro-Engineering and Cognitive Science, University of Houston, TX, USA
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48
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Chicherov V, Herzog MH. Targets but not flankers are suppressed in crowding as revealed by EEG frequency tagging. Neuroimage 2015; 119:325-31. [PMID: 26102568 DOI: 10.1016/j.neuroimage.2015.06.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/13/2015] [Accepted: 06/16/2015] [Indexed: 10/23/2022] Open
Abstract
Perception of a visual target can strongly deteriorate in the presence of flanking elements (crowding). For example, adding lines next to a vernier makes vernier offset discrimination difficult. Crowding is often considered a bottleneck of low-level vision, determined by the unavoidable limitations of the early visual system. In accordance with this proposal, neural processing of the flankers should be impaired in crowding as much as that of the target. To test this prediction, we used steady-state visually evoked potentials (ssVEPs) to separate target responses from flanker responses. We presented a vernier target either alone or flanked by lines, which had the same color as the vernier or a different color. Crowding by same-color flankers was stronger than by different-color flankers. Mirroring the behavioral results, ssVEP amplitudes corresponding to the target were higher for different-color flankers than for same-color flankers. Flanker related ssVEPs, however, did not depend on crowding strength. It seems that target, but not flanker processing, is susceptible to crowding. In line with previous results, we suggest that crowding is not caused by low-level interferences but is linked to target-flanker grouping instead.
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Affiliation(s)
- Vitaly Chicherov
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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Herzog MH, Manassi M. Uncorking the bottleneck of crowding: a fresh look at object recognition. Curr Opin Behav Sci 2015. [DOI: 10.1016/j.cobeha.2014.10.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Herzog MH, Sayim B, Chicherov V, Manassi M. Crowding, grouping, and object recognition: A matter of appearance. J Vis 2015; 15:5. [PMID: 26024452 PMCID: PMC4429926 DOI: 10.1167/15.6.5] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Indexed: 11/24/2022] Open
Abstract
In crowding, the perception of a target strongly deteriorates when neighboring elements are presented. Crowding is usually assumed to have the following characteristics. (a) Crowding is determined only by nearby elements within a restricted region around the target (Bouma's law). (b) Increasing the number of flankers can only deteriorate performance. (c) Target-flanker interference is feature-specific. These characteristics are usually explained by pooling models, which are well in the spirit of classic models of object recognition. In this review, we summarize recent findings showing that crowding is not determined by the above characteristics, thus, challenging most models of crowding. We propose that the spatial configuration across the entire visual field determines crowding. Only when one understands how all elements of a visual scene group with each other, can one determine crowding strength. We put forward the hypothesis that appearance (i.e., how stimuli look) is a good predictor for crowding, because both crowding and appearance reflect the output of recurrent processing rather than interactions during the initial phase of visual processing.
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