1
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Knight RS, Chen T, Center EG, Gratton G, Fabiani M, Savazzi S, Mazzi C, Beck DM. Bypassing input to V1 in visual awareness: A TMS-EROS investigation. Neuropsychologia 2024; 198:108864. [PMID: 38521150 PMCID: PMC11194103 DOI: 10.1016/j.neuropsychologia.2024.108864] [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: 10/16/2023] [Revised: 02/07/2024] [Accepted: 03/18/2024] [Indexed: 03/25/2024]
Abstract
Early visual cortex (V1-V3) is believed to be critical for normal visual awareness by providing the necessary feedforward input. However, it remains unclear whether visual awareness can occur without further involvement of early visual cortex, such as re-entrant feedback. It has been challenging to determine the importance of feedback activity to these areas because of the difficulties in dissociating this activity from the initial feedforward activity. Here, we applied single-pulse transcranial magnetic stimulation (TMS) over the left posterior parietal cortex to elicit phosphenes in the absence of direct visual input to early visual cortex. Immediate neural activity after the TMS pulse was assessed using the event-related optical signal (EROS), which can measure activity under the TMS coil without artifacts. Our results show that: 1) The activity in posterior parietal cortex 50 ms after TMS was related to phosphene awareness, and 2) Activity related to awareness was observed in a small portion of V1 140 ms after TMS, but in contrast (3) Activity in V2 was a more robust correlate of awareness. Together, these results are consistent with interactive models proposing that sustained and recurrent loops of activity between cortical areas are necessary for visual awareness to emerge. In addition, we observed phosphene-related activations of the anteromedial cuneus and lateral occipital cortex, suggesting a functional network subserving awareness comprising these regions, the parietal cortex and early visual cortex.
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Affiliation(s)
- Ramisha S Knight
- Beckman Institute, University of Illinois.405 N Mathews Avenue, Urbana, IL, USA; Aptima, Inc. 2555 University Blvd, Fairborn, OH, USA
| | - Tao Chen
- Beckman Institute, University of Illinois.405 N Mathews Avenue, Urbana, IL, USA; Department of Psychology, University of Illinois. 601 E John Street, Champaign, IL, USA.
| | - Evan G Center
- Beckman Institute, University of Illinois.405 N Mathews Avenue, Urbana, IL, USA; Department of Psychology, University of Illinois. 601 E John Street, Champaign, IL, USA; Center for Ubiquitous Computing, University of Oulu, Oulu, Finland
| | - Gabriele Gratton
- Beckman Institute, University of Illinois.405 N Mathews Avenue, Urbana, IL, USA; Department of Psychology, University of Illinois. 601 E John Street, Champaign, IL, USA
| | - Monica Fabiani
- Beckman Institute, University of Illinois.405 N Mathews Avenue, Urbana, IL, USA; Department of Psychology, University of Illinois. 601 E John Street, Champaign, IL, USA
| | - Silvia Savazzi
- Perception and Awareness (PandA) Lab, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Chiara Mazzi
- Perception and Awareness (PandA) Lab, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Diane M Beck
- Beckman Institute, University of Illinois.405 N Mathews Avenue, Urbana, IL, USA; Department of Psychology, University of Illinois. 601 E John Street, Champaign, IL, USA.
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2
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Carlson BM, Mitchell BA, Dougherty K, Westerberg JA, Cox MA, Maier A. Does V1 response suppression initiate binocular rivalry? iScience 2023; 26:107359. [PMID: 37520732 PMCID: PMC10382945 DOI: 10.1016/j.isci.2023.107359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/02/2023] [Accepted: 07/07/2023] [Indexed: 08/01/2023] Open
Abstract
During binocular rivalry (BR) only one eye's view is perceived. Neural underpinnings of BR are debated. Recent studies suggest that primary visual cortex (V1) initiates BR. One trigger might be response suppression across most V1 neurons at the onset of BR. Here, we utilize a variant of BR called binocular rivalry flash suppression (BRFS) to test this hypothesis. BRFS is identical to BR, except stimuli are shown with a ∼1s delay. If V1 response suppression was required to initiate BR, it should occur during BRFS as well. To test this, we compared V1 spiking in two macaques observing BRFS. We found that BRFS resulted in response facilitation rather than response suppression across V1 neurons. However, BRFS still reduces responses in a subset of V1 neurons due to the adaptive effects of asynchronous stimulus presentation. We argue that this selective response suppression could serve as an alternate initiator of BR.
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Affiliation(s)
- Brock M. Carlson
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
| | - Blake A. Mitchell
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
| | - Kacie Dougherty
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
- Department of Psychology, Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
| | - Jacob A. Westerberg
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam 1105 BA, the Netherlands
| | - Michele A. Cox
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
| | - Alexander Maier
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
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3
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Phylactou P, Shimi A, Konstantinou N. Causal evidence for the role of the sensory visual cortex in visual short-term memory maintenance. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230321. [PMID: 37090966 PMCID: PMC10113812 DOI: 10.1098/rsos.230321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
The role of the sensory visual cortex during visual short-term memory (VSTM) remains controversial. This controversy is possibly due to methodological issues in previous attempts to investigate the effects of transcranial magnetic stimulation (TMS) on VSTM. The aim of this study was to use TMS, while covering previous methodological deficits. Sixty-four young adults were recruited to participate in two experiments (Experiment 1: n = 36; Experiment 2: n = 28) using a VSTM orientation change-detection task under TMS. Monocular vision was ensured using red-blue goggles combined with red-blue stimuli. Double-pulse TMS was delivered at different times (Experiment 1: 0, 200 or 1000 ms; Experiment 2: 200, 1000 ms) during a 2 s maintenance phase, on one side of the occipital hemisphere. In Experiment 2, a sham TMS condition was introduced. Decreased detection sensitivity (d') in the ipsilateral occipital hemisphere to visual hemifield, and in the real TMS (compared with sham TMS) condition indicated inhibitory TMS effects, and thus, a causal involvement of the sensory visual cortex during early (200 ms) and late (1000 ms) maintenance in VSTM. These findings are aligned with sensory recruitment, which proposes that both perceptual and memory processes rely upon the same neural substrates in the sensory visual cortex. The methods used in this study were preregistered and had received in-principle acceptance on 6 June 2022 (Stage 1 protocol can be found in: https://doi.org/10.17605/OSF.IO/EMPDT).
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Affiliation(s)
- Phivos Phylactou
- Department of Rehabilitation Sciences, Faculty of Health Sciences, Cyprus University of Technology, Limassol 3041, Cyprus
| | - Andria Shimi
- Department of Psychology, Faculty of Social Sciences and Education, University of Cyprus, CY-1678 Nicosia, Cyprus
| | - Nikos Konstantinou
- Department of Rehabilitation Sciences, Faculty of Health Sciences, Cyprus University of Technology, Limassol 3041, Cyprus
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4
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Mo C, Lu J, Shi C, Fang F. Neural representations of competing stimuli along the dorsal and ventral visual pathways during binocular rivalry. Cereb Cortex 2023; 33:2734-2747. [PMID: 35689650 DOI: 10.1093/cercor/bhac238] [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: 01/26/2022] [Revised: 05/07/2022] [Accepted: 05/08/2022] [Indexed: 11/14/2022] Open
Abstract
Binocular rivalry arises when two discrepant stimuli are simultaneously presented to different eyes, during which observers consciously experience vivid perceptual alternations without physical changes in visual inputs. Neural dynamics tracking such perceptual alternations have been identified at both early and late visual areas, leading to the fundamental debate concerning the primary neural substrate underlying binocular rivalry. One promising hypothesis that might reconcile these seemingly paradoxical findings is a gradual shift from interocular competition between monocular neurons to pattern competition among binocular neurons. Here, we examined this hypothesis by investigating how neural representations of rivalrous stimuli evolved along the visual pathway. We found that representations of the dominant and the suppressed stimuli initially co-existed in V1, which were enhanced and attenuated respectively in extrastriate visual areas. Notably, neural activity in V4 was dictated by the representation of the dominant stimulus, while the representation of the suppressed stimulus was only partially inhibited in dorsal areas V3A and MT+. Our findings revealed a progressive transition from the co-existing representations of the rivalrous inputs to the dictatorial representation of the dominant stimulus in the ventral pathway, and advocated different cortical evolutionary patterns of visual representations between the dorsal and the ventral pathways.
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Affiliation(s)
- Ce Mo
- Department of Psychology, Sun Yat-Sen University, Guangzhou 510006, Guangdong, China
| | - Junshi Lu
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100087, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100087, China
| | - Chao Shi
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100087, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100087, China
| | - Fang Fang
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100087, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100087, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100087, China
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5
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Higgins NC, Scurry AN, Jiang F, Little DF, Alain C, Elhilali M, Snyder JS. Adaptation in the sensory cortex drives bistable switching during auditory stream segregation. Neurosci Conscious 2023; 2023:niac019. [PMID: 36751309 PMCID: PMC9899071 DOI: 10.1093/nc/niac019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/17/2022] [Accepted: 12/26/2022] [Indexed: 02/06/2023] Open
Abstract
Current theories of perception emphasize the role of neural adaptation, inhibitory competition, and noise as key components that lead to switches in perception. Supporting evidence comes from neurophysiological findings of specific neural signatures in modality-specific and supramodal brain areas that appear to be critical to switches in perception. We used functional magnetic resonance imaging to study brain activity around the time of switches in perception while participants listened to a bistable auditory stream segregation stimulus, which can be heard as one integrated stream of tones or two segregated streams of tones. The auditory thalamus showed more activity around the time of a switch from segregated to integrated compared to time periods of stable perception of integrated; in contrast, the rostral anterior cingulate cortex and the inferior parietal lobule showed more activity around the time of a switch from integrated to segregated compared to time periods of stable perception of segregated streams, consistent with prior findings of asymmetries in brain activity depending on the switch direction. In sound-responsive areas in the auditory cortex, neural activity increased in strength preceding switches in perception and declined in strength over time following switches in perception. Such dynamics in the auditory cortex are consistent with the role of adaptation proposed by computational models of visual and auditory bistable switching, whereby the strength of neural activity decreases following a switch in perception, which eventually destabilizes the current percept enough to lead to a switch to an alternative percept.
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Affiliation(s)
- Nathan C Higgins
- Department of Communication Sciences and Disorders, University of South Florida, 4202 E. Fowler Avenue, PCD1017, Tampa, FL 33620, USA
| | - Alexandra N Scurry
- Department of Psychology, University of Nevada, 1664 N. Virginia Street Mail Stop 0296, Reno, NV 89557, USA
| | - Fang Jiang
- Department of Psychology, University of Nevada, 1664 N. Virginia Street Mail Stop 0296, Reno, NV 89557, USA
| | - David F Little
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Claude Alain
- Rotman Research Institute, Baycrest Health Sciences, 3560 Bathurst Street, Toronto, ON M6A 2E1, Canada
| | - Mounya Elhilali
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Joel S Snyder
- Department of Psychology, University of Nevada, 4505 Maryland Parkway Mail Stop 5030, Las Vegas, NV 89154, USA
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6
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Conscious interpretation: A distinct aspect for the neural markers of the contents of consciousness. Conscious Cogn 2023; 108:103471. [PMID: 36736210 DOI: 10.1016/j.concog.2023.103471] [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: 07/29/2022] [Revised: 12/22/2022] [Accepted: 01/11/2023] [Indexed: 02/04/2023]
Abstract
Progress in the science of consciousness depends on the experimental paradigms and varieties of contrastive analysis available to researchers. Here we highlight paradigms where the object is represented in consciousness as a set of its features but the interpretation of this set alternates in consciousness. We group experimental paradigms with this property under the label "conscious interpretation". We compare the paradigms studying conscious interpretation of the already consciously perceived objects with other types of experimental paradigms. We review previous and recent studies investigating this interpretative aspect of consciousness and propose future directions. We put forward the hypothesis that there are types of stimuli with a hierarchy of interpretations for which the rule applies: conscious experience is drawn towards higher-level interpretation and reverting back to the lower level of interpretation is impossible. We discuss how theories of consciousness might incorporate knowledge and constraints arising from the characteristics of conscious interpretation.
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7
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Barkdoll K, Lu Y, Barranca VJ. New insights into binocular rivalry from the reconstruction of evolving percepts using model network dynamics. Front Comput Neurosci 2023; 17:1137015. [PMID: 37034441 PMCID: PMC10079880 DOI: 10.3389/fncom.2023.1137015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
When the two eyes are presented with highly distinct stimuli, the resulting visual percept generally switches every few seconds between the two monocular images in an irregular fashion, giving rise to a phenomenon known as binocular rivalry. While a host of theoretical studies have explored potential mechanisms for binocular rivalry in the context of evoked model dynamics in response to simple stimuli, here we investigate binocular rivalry directly through complex stimulus reconstructions based on the activity of a two-layer neuronal network model with competing downstream pools driven by disparate monocular stimuli composed of image pixels. To estimate the dynamic percept, we derive a linear input-output mapping rooted in the non-linear network dynamics and iteratively apply compressive sensing techniques for signal recovery. Utilizing a dominance metric, we are able to identify when percept alternations occur and use data collected during each dominance period to generate a sequence of percept reconstructions. We show that despite the approximate nature of the input-output mapping and the significant reduction in neurons downstream relative to stimulus pixels, the dominant monocular image is well-encoded in the network dynamics and improvements are garnered when realistic spatial receptive field structure is incorporated into the feedforward connectivity. Our model demonstrates gamma-distributed dominance durations and well obeys Levelt's four laws for how dominance durations change with stimulus strength, agreeing with key recurring experimental observations often used to benchmark rivalry models. In light of evidence that individuals with autism exhibit relatively slow percept switching in binocular rivalry, we corroborate the ubiquitous hypothesis that autism manifests from reduced inhibition in the brain by systematically probing our model alternation rate across choices of inhibition strength. We exhibit sufficient conditions for producing binocular rivalry in the context of natural scene stimuli, opening a clearer window into the dynamic brain computations that vary with the generated percept and a potential path toward further understanding neurological disorders.
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8
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Skerswetat J, Bex PJ. InFoRM (Indicate-Follow-Replay-Me): A novel method to measure perceptual multistability dynamics using continuous data tracking and validated estimates of visual introspection. Conscious Cogn 2023; 107:103437. [PMID: 36450218 PMCID: PMC9840704 DOI: 10.1016/j.concog.2022.103437] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/29/2022]
Abstract
Perceptual multistability, e.g. Binocular Rivalry, has been intensively used as a tool to study visual consciousness. Current methods to assess multistability do not capture all potentially occurring perceptual states, provide no estimate of introspection, and lack continuous, high-temporal resolution to resolve perceptual changes between states and within mixed perceptual states. We introduce InFoRM (Indicate-Follow-Replay-Me), a four-phase method that (1) trains a participant to self-generate estimates of perceptual introspection-maps that are (2) validated during a physical mimic task, (3) gathers perceptual multistability data, and (4) confirms their validity during a physical replay. 28 condition-blinded adults performed InFoRM while experiencing binocular rivalry evoked with orthogonal sinusoidal gratings. A 60 Hz joystick (3600 data samples/minute) was used to indicate continuously changes across six perceptual states within each 1 min trial. A polarized monitor system was used to present the stimuli dichoptically. Three contrast conditions were investigated: low vs low, high vs high, and low vs high. InFoRM replicates standard outcome measures, i.e. alternation rate, mean and relative proportions of perception, and distribution of exclusive percepts that are well fitted with gamma functions. Furthermore, InFoRM generates novel outcomes that deliver new insights in visual cognition via estimates of introspection maps, in ocular dominance via perceptual-state-specific dominance scores, in transitory dynamics between and within perceptual states, via techniques adopted from eye-tracking, and in rivalry-zone-size estimates utilizing InFoRM's ability to simulate piecemeal perception. The replay phase (physical replay of perceptual rivalry) confirmed good overall agreement (73% ±5 standard deviation). InFoRM can be applied to other multistable paradigms and can be used to study visual consciousness in typical and neuro-atypical populations.
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Affiliation(s)
- Jan Skerswetat
- Department of Psychology, Northeastern University, 360 Huntington Ave, Boston, MA 02115, United States.
| | - Peter J Bex
- Department of Psychology, Northeastern University, 360 Huntington Ave, Boston, MA 02115, United States
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9
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Lee SM, Slezak E, Shevell SK. Ambiguity is a linking feature for interocular grouping. J Vis 2022; 22:12. [PMID: 36264654 PMCID: PMC9587512 DOI: 10.1167/jov.22.11.12] [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] [Indexed: 11/24/2022] Open
Abstract
Ambiguity is implicit in neural representations of the physical world. Previous work has examined how the visual system resolves ambiguous neural signals that represent various features, such as the percept resulting from rivalrous chromaticities or forms. Relatively little is known, however, about the contribution of unambiguous neural representations to perceptual resolution of ambiguous ones. This is addressed here by measuring perceptual resolution of ambiguity by grouping, which is operationalized as the tendency for multiple similar ambiguous representations to be seen as identical to each other. Multiple chromatically ambiguous representations were created using interocular switch rivalry and presented together with a nearby but separate unambiguous (non-rivalrous) chromaticity. The magnitude of grouping the chromatic regions was compared when ambiguous regions were seen alone versus with unambiguous regions seen simultaneously. Contrary to prevailing theory that the resolution of the ambiguous percepts would follow the unambiguous ones, the ambiguous chromatic regions consistently appeared identical to each other, but their appearance was not found to be attracted to the unambiguous color percept. This supports the proposition that the ambiguity itself in a neural representation is a linking feature contributing to perceptual disambiguation.
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Affiliation(s)
- Sunny M Lee
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL, USA.,
| | - Emily Slezak
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL, USA.,
| | - Steven K Shevell
- Department of Psychology and Institute for Mind and Biology, University of Chicago, Chicago, IL, USA.,Department of Ophthalmology & Visual Science, University of Chicago, Chicago, IL, USA.,
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10
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Ono M, Hirose N, Mori S. Tactile information affects alternating visual percepts during binocular rivalry using naturalistic objects. Cogn Res Princ Implic 2022; 7:40. [PMID: 35543826 PMCID: PMC9095789 DOI: 10.1186/s41235-022-00390-w] [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: 02/14/2020] [Accepted: 04/17/2022] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION Past studies have provided evidence that the effects of tactile stimulation on binocular rivalry are mediated by primitive features (orientation and spatial frequency) common in vision and touch. In this study, we examined whether such effects on binocular rivalry can be obtained through the roughness of naturalistic objects. In three experiments, the total dominant time of visual percepts of two objects was measured under binocular rivalry when participants touched one of the objects. RESULT In Experiment 1, the total dominant time for the image of artificial turf and bathmat was prolonged by congruent tactile stimulation and shortened by incongruent tactile stimulation. In Experiment 2, we used the same stimuli but rotated their visual images in opposite directions. The dominant time for either image was prolonged by congruent tactile stimulation. In Experiment 3, we used different types of stimuli, smooth marble and rough fabric, and noted significant effects of the congruent and incongruent tactile stimulation on the dominant time of visual percepts. CONCLUSION These three experiments demonstrated that visuo-tactile interaction on binocular rivalry can be mediated by roughness.
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Affiliation(s)
- Mikoto Ono
- grid.177174.30000 0001 2242 4849Department of Informatics, Graduate school of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka City, Fukuoka 819-0395 Japan
| | - Nobuyuki Hirose
- grid.177174.30000 0001 2242 4849Department of Informatics, Graduate school of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka City, Fukuoka 819-0395 Japan
| | - Shuji Mori
- grid.177174.30000 0001 2242 4849Department of Informatics, Graduate school of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka City, Fukuoka 819-0395 Japan
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11
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DiNuzzo M, Mangia S, Moraschi M, Mascali D, Hagberg GE, Giove F. Perception is associated with the brain's metabolic response to sensory stimulation. eLife 2022; 11:71016. [PMID: 35225790 PMCID: PMC9038191 DOI: 10.7554/elife.71016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 02/25/2022] [Indexed: 11/13/2022] Open
Abstract
Processing of incoming sensory stimulation triggers an increase of cerebral perfusion and blood oxygenation (neurovascular response) as well as an alteration of the metabolic neurochemical profile (neurometabolic response). Here we show in human primary visual cortex (V1) that perceived and unperceived isoluminant chromatic flickering stimuli designed to have similar neurovascular responses as measured by blood oxygenation level dependent functional MRI (BOLD-fMRI) have markedly different neurometabolic responses as measured by functional MRS. In particular, a significant regional buildup of lactate, an index of aerobic glycolysis, and glutamate, an index of malate-aspartate shuttle, occurred in V1 only when the flickering was perceived, without any relation with behavioral or physiological variables. Whereas the BOLD-fMRI signal in V1, a proxy for input to V1, was insensitive to flickering perception by design, the BOLD-fMRI signal in secondary visual areas was larger during perceived than unperceived flickering, indicating increased output from V1. These results demonstrate that the upregulation of energy metabolism induced by visual stimulation depends on the type of information processing taking place in V1, and that 1H-fMRS provides unique information about local input/output balance that is not measured by BOLD fMRI.
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Affiliation(s)
- Mauro DiNuzzo
- Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, Italy
| | - Silvia Mangia
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, United States
| | - Marta Moraschi
- Department of Radiation Oncology, University of Rome, Rome, Italy
| | - Daniele Mascali
- Dipartimento di Neuroscienze, Università Gabriele D'Annunzio, Chieti, Italy
| | - Gisela E Hagberg
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics and Biomedical Magnetic Resonance, Tübingen, Germany
| | - Federico Giove
- Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, Italy
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12
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MRI Stereoscope: A Miniature Stereoscope for Human Neuroimaging. eNeuro 2022; 9:ENEURO.0382-21.2021. [PMID: 35045974 PMCID: PMC8856700 DOI: 10.1523/eneuro.0382-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 11/29/2022] Open
Abstract
Stereoscopic vision enables the perception of depth. To study the brain mechanisms behind stereoscopic vision using noninvasive brain imaging (magnetic resonance brain imaging; MRI), scientists need to reproduce the independent views of the left and right eyes in the brain scanner using "dichoptic" displays. However, high-quality dichoptic displays are technically challenging and costly to implement in the MRI scanner. The novel miniature stereoscope system ("MRI stereoscope") is an affordable and open-source tool that displays high-quality dichoptic images inside the MRI scanner. The MRI stereoscope takes advantage of commonly used display equipment, the MRI head coil, and a display screen. To validate the MRI stereoscope, binocular disparity stimuli were presented in a 3T MRI scanner while neural activation was recorded using functional MRI in six human participants. The comparison of large binocular disparities compared with disparities close to zero evoked strong responses across dorsal and ventral extra-striate visual cortex. In contrast, binocularly anti-correlated stimuli, which are not perceived in depth, did not evoke comparable activation. These results are the proof-of-concept that the MRI stereoscope can deliver dichoptic images that produce the perception of stereoscopic depth during acquisition of MR responses. Application of the MRI stereoscope to neuroscience can help to address important questions in perception and consciousness.
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13
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Klimova M, Ling S. Davida reorients intermediate visual processing. Cogn Neuropsychol 2022; 39:88-91. [PMID: 35588248 PMCID: PMC10928806 DOI: 10.1080/02643294.2022.2052719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/11/2022] [Accepted: 03/08/2022] [Indexed: 11/03/2022]
Affiliation(s)
- Michaela Klimova
- Department of Psychological and Brain Sciences, Boston University, Boston, MA
- Center for Systems Neuroscience, Boston University, Boston, MA
| | - Sam Ling
- Department of Psychological and Brain Sciences, Boston University, Boston, MA
- Center for Systems Neuroscience, Boston University, Boston, MA
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14
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Devia C, Concha-Miranda M, Rodríguez E. Bi-Stable Perception: Self-Coordinating Brain Regions to Make-Up the Mind. Front Neurosci 2022; 15:805690. [PMID: 35153663 PMCID: PMC8829010 DOI: 10.3389/fnins.2021.805690] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022] Open
Abstract
Bi-stable perception is a strong instance of cognitive self-organization, providing a research model for how ‘the brain makes up its mind.’ The complexity of perceptual bistability prevents a simple attribution of functions to areas, because many cognitive processes, recruiting multiple brain regions, are simultaneously involved. The functional magnetic resonance imaging (fMRI) evidence suggests the activation of a large network of distant brain areas. Concurrently, electroencephalographic and magnetoencephalographic (MEEG) literature shows sub second oscillatory activity and phase synchrony on several frequency bands. Strongly represented are beta and gamma bands, often associated with neural/cognitive integration processes. The spatial extension and short duration of brain activities suggests the need for a fast, large-scale neural coordination mechanism. To address the range of temporo-spatial scales involved, we systematize the current knowledge from mathematical models, cognitive sciences and neuroscience at large, from single-cell- to system-level research, including evidence from human and non-human primates. Surprisingly, despite evidence spanning through different organization levels, models, and experimental approaches, the scarcity of integrative studies is evident. In a final section of the review we dwell on the reasons behind such scarcity and on the need of integration in order to achieve a real understanding of the complexities underlying bi-stable perception processes.
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Affiliation(s)
- Christ Devia
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | - Miguel Concha-Miranda
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Laboratorio de Neurodinámica Básica y Aplicada, Escuela de Psicología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Eugenio Rodríguez
- Laboratorio de Neurodinámica Básica y Aplicada, Escuela de Psicología, Pontificia Universidad Católica de Chile, Santiago, Chile
- *Correspondence: Eugenio Rodríguez,
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15
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Torralba Cuello M, Drew A, Sabaté San José A, Morís Fernández L, Soto-Faraco S. Alpha fluctuations regulate the accrual of visual information to awareness. Cortex 2021; 147:58-71. [PMID: 35021126 DOI: 10.1016/j.cortex.2021.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/21/2021] [Accepted: 11/23/2021] [Indexed: 01/26/2023]
Abstract
Endogenous brain processes play a paramount role in shaping up perceptual phenomenology. This is illustrated by the alternations experienced by humans (and other animals) when watching perceptually ambiguous, static images. We hypothesised that endogenous alpha fluctuations in the visual cortex pace the accumulation of sensory information leading to perceptual outcomes. Here, we addressed this hypothesis using binocular rivalry combined with visual entrainment and electroencephalography in humans (64 female, 53 male). The results revealed a correlation between the individual frequency of alpha oscillations in the occipital cortex and perceptual alternation rates experienced during binocular rivalry. In subsequent experiments we show that regulating endogenous brain activity via rhythmic entrainment produced corresponding changes in perceptual alternation rate. These changes were observed only in the alpha range but not at lower entrainment frequencies, and were much reduced when using arrhythmic stimulation. Additionally, entraining at frequencies above the alpha range did not result in speeding up perceptual alternation rates. Overall, these findings support the notion that visual information is accumulated via alpha cycles to promote the emergence of conscious perceptual representations. We suggest that models of binocular rivalry incorporating posterior alpha as a pacemaker can provide an important advance in the comprehension of the dynamics of visual awareness.
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Affiliation(s)
- Mireia Torralba Cuello
- Multisensory Research Group, Center for Brain and Cognition, University of Pompeu Fabra, Barcelona, Spain.
| | - Alice Drew
- Multisensory Research Group, Center for Brain and Cognition, University of Pompeu Fabra, Barcelona, Spain
| | | | - Luis Morís Fernández
- Multisensory Research Group, Center for Brain and Cognition, University of Pompeu Fabra, Barcelona, Spain
| | - Salvador Soto-Faraco
- Multisensory Research Group, Center for Brain and Cognition, University of Pompeu Fabra, Barcelona, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
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16
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Kurita Y, Urakawa T, Araki O. Involvement of Visual Mismatch Negativity in Access Processing to Visual Awareness. Front Hum Neurosci 2021; 15:757411. [PMID: 34803638 PMCID: PMC8603928 DOI: 10.3389/fnhum.2021.757411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/21/2021] [Indexed: 11/26/2022] Open
Abstract
Psychophysiological studies with electroencephalography, focusing on the dynamical aspect of neural correlate of consciousness, reported that visual awareness negativity and P3 enhancement are observed at a latency, 200–300 ms after the visual stimulus onset, when the visual stimulus is consciously perceived. However, access processing to visual awareness (APVA) immediately before conscious perception still remains at the earlier stage of visual sensory processing, though there is little known regarding this subject. The present study hypothesized that visual mismatch negativity (vMMN), which reflects automatic change detection at a latency of 130–250 ms, might be involved in the APVA. In a previous study, vMMN was reported to be evoked by the deviant stimulus that is not consciously perceived in binocular rivalry. To clarify whether the visual change detection affects APVA, we conducted a modified experiment of oddball paradigm on binocular rivalry. The results showed a significant correlation between enhancement of vMMN amplitude and facilitation of perceptual alternation when the unconscious deviant was presented. This implies that vMMN is relevant to the APVA, which is a novel role of vMMN. In early visual processing, the attentional mechanism associated with vMMN is suggested to play an important role in unconscious neural processing at an earlier stage of visual awareness.
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Affiliation(s)
- Yuki Kurita
- Department of Applied Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Tomokazu Urakawa
- Department of Applied Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Osamu Araki
- Department of Applied Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
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17
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Watanabe T. Causal roles of prefrontal cortex during spontaneous perceptual switching are determined by brain state dynamics. eLife 2021; 10:69079. [PMID: 34713803 PMCID: PMC8631941 DOI: 10.7554/elife.69079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 10/28/2021] [Indexed: 12/23/2022] Open
Abstract
The prefrontal cortex (PFC) is thought to orchestrate cognitive dynamics. However, in tests of bistable visual perception, no direct evidence supporting such presumable causal roles of the PFC has been reported except for a recent work. Here, using a novel brain-state-dependent neural stimulation system, we identified causal effects on percept dynamics in three PFC activities—right frontal eye fields, dorsolateral PFC (DLPFC), and inferior frontal cortex (IFC). The causality is behaviourally detectable only when we track brain state dynamics and modulate the PFC activity in brain-state-/state-history-dependent manners. The behavioural effects are underpinned by transient neural changes in the brain state dynamics, and such neural effects are quantitatively explainable by structural transformations of the hypothetical energy landscapes. Moreover, these findings indicate distinct functions of the three PFC areas: in particular, the DLPFC enhances the integration of two PFC-active brain states, whereas IFC promotes the functional segregation between them. This work resolves the controversy over the PFC roles in spontaneous perceptual switching and underlines brain state dynamics in fine investigations of brain-behaviour causality. A cube that seems to shift its spatial arrangement as you keep looking; the elegant silhouette of a pirouetting dancer, which starts to spin in the opposite direction the more you stare at it; an illustration that shows two profiles – or is it a vase? These optical illusions are examples of bistable visual perception. Beyond their entertaining aspect, they provide a way for scientists to explore the dynamics of human consciousness, and the neural regions involved in this process. Some studies show that bistable visual perception is associated with the activation of the prefrontal cortex, a brain area involved in complex cognitive processes. However, it is unclear whether this region is required for the illusions to emerge. Some research has showed that even if sections of the prefrontal cortex are temporally deactivated, participants can still experience the illusions. Instead, Takamitsu Watanabe proposes that bistable visual perception is a process tied to dynamic brain states – that is, that distinct regions of the prefontal cortex are required for this fluctuating visual awareness, depending on the state of the whole brain. Such causal link cannot be observed if brain activity is not tracked closely. To investigate this, the brain states of 65 participants were recorded as individuals were experiencing the optical illusions; the activity of their various brain regions could therefore be mapped, and then areas of the prefrontal cortex could precisely be inhibited at the right time using transcranial magnetic stimulation. This revealed that, indeed, prefrontal cortex regions were necessary for bistable visual perception, but not in a simple way. Instead, which ones were required and when depended on activity dynamics taking place in the whole brain. Overall, these results indicate that monitoring brain states is necessary to better understand – and ultimately, control – the neural pathways underlying perception and behaviour.
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Affiliation(s)
- Takamitsu Watanabe
- International Research Centre for Neurointelligence, The University of Tokyo Institutes for Advanced Study, Tokyo, Japan.,RIKEN Centre for Brain Science, Saitama, Japan
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18
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Chang DH, Waring GO, Hom M, Barnett M. Presbyopia Treatments by Mechanism of Action: A New Classification System Based on a Review of the Literature. Clin Ophthalmol 2021; 15:3733-3745. [PMID: 34522079 PMCID: PMC8432361 DOI: 10.2147/opth.s318065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 07/08/2021] [Indexed: 01/07/2023] Open
Abstract
Presbyopia, a loss of accommodative ability associated with aging, is a significant cause of vision impairment globally. At the clinical level, it is a frustrating and difficult issue that negatively impacts patients’ quality of life. Less appreciated is the fact that loss of accommodative ability and its current treatments methods may present safety concerns, for example, increasing the risk of falls. Therefore, a more complete understanding of treatment options with respect to how they relate to the natural ability of the eye is needed to improve decision making and to aid clinicians in individualizing treatment options. This article reviews the options for expanding functional through focus—a term coined to describe the ability of the eye to see at all distances with minimal latency—by how they vary the refractive power over time, across the visual field, between eyes, or across a range of distances. ![]()
Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/HZw7qvIu6pw
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Affiliation(s)
| | | | | | - Melissa Barnett
- University of California, Davis Eye Center, Sacramento, CA, USA
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19
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Brascamp JW, de Hollander G, Wertheimer MD, DePew AN, Knapen T. Separable pupillary signatures of perception and action during perceptual multistability. eLife 2021; 10:66161. [PMID: 34378532 PMCID: PMC8378849 DOI: 10.7554/elife.66161] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 08/11/2021] [Indexed: 02/04/2023] Open
Abstract
The pupil provides a rich, non-invasive measure of the neural bases of perception and cognition and has been of particular value in uncovering the role of arousal-linked neuromodulation, which alters both cortical processing and pupil size. But pupil size is subject to a multitude of influences, which complicates unique interpretation. We measured pupils of observers experiencing perceptual multistability-an ever-changing subjective percept in the face of unchanging but inconclusive sensory input. In separate conditions, the endogenously generated perceptual changes were either task-relevant or not, allowing a separation between perception-related and task-related pupil signals. Perceptual changes were marked by a complex pupil response that could be decomposed into two components: a dilation tied to task execution and plausibly indicative of an arousal-linked noradrenaline surge, and an overlapping constriction tied to the perceptual transient and plausibly a marker of altered visual cortical representation. Constriction, but not dilation, amplitude systematically depended on the time interval between perceptual changes, possibly providing an overt index of neural adaptation. These results show that the pupil provides a simultaneous reading on interacting but dissociable neural processes during perceptual multistability, and suggest that arousal-linked neuromodulator release shapes action but not perception in these circumstances.
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Affiliation(s)
- Jan W Brascamp
- Michigan State University, Department of Psychology, East Lansing, United States.,Michigan State University, Neuroscience Program, East Lansing, United States
| | - Gilles de Hollander
- Zurich Center for Neuroeconomics, Department of Economics, University of Zurich, Zurich, Switzerland
| | - Michael D Wertheimer
- Michigan State University, Department of Psychology, East Lansing, United States
| | - Ashley N DePew
- Michigan State University, Department of Psychology, East Lansing, United States
| | - Tomas Knapen
- Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Spinoza Centre for Neuroimaging, Royal Academy of Sciences, Amsterdam, Netherlands
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20
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Abstract
Studies utilizing continuous flash suppression (CFS) provide valuable information regarding conscious and nonconscious perception. There are, however, crucial unanswered questions regarding the mechanisms of suppression and the level of visual processing in the absence of consciousness with CFS. Research suggests that the answers to these questions depend on the experimental configuration and how we assess consciousness in these studies. The aim of this review is to evaluate the impact of different experimental configurations and the assessment of consciousness on the results of the previous CFS studies. We review studies that evaluated the influence of different experimental configuration on the depth of suppression with CFS and discuss how different assessments of consciousness may impact the results of CFS studies. Finally, we review behavioral and brain recording studies of CFS. In conclusion, previous studies provide evidence for survival of low-level visual information and complete impairment of high-level visual information under the influence of CFS. That is, studies suggest that nonconscious perception of lower-level visual information happens with CFS, but there is no evidence for nonconscious high-level recognition with CFS.
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21
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Zacharia AA, Ahuja N, Kaur S, Sharma R. Frontal activation as a key for deciphering context congruity and valence during visual perception: An electrical neuroimaging study. Brain Cogn 2021; 150:105711. [PMID: 33774336 DOI: 10.1016/j.bandc.2021.105711] [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: 10/23/2020] [Revised: 01/12/2021] [Accepted: 02/24/2021] [Indexed: 11/20/2022]
Abstract
The object-context associations and the valence are two important stimulus attributes that influence visual perception. The current study investigates the neural sources associated with schema congruent and incongruent object-context associations within positive, negative, and neutral valence during an intermittent binocular rivalry task with simultaneous high-density EEG recording. Cortical sourceswere calculated using the sLORETA algorithm in 150 ms after stimulus onset (Stim + 150) and 400 ms before response (Resp-400) time windows. No significant difference in source activity was found between congruent and incongruent associations in any of the valence categories in the Stim + 150 ms window indicating that immediately after stimulus presentation the basic visual processing remains the same for both. In the Resp-400 ms window, different frontal regions showed higher activity for incongruent associations with different valence such as the superior frontal gyrus showed significantly higher activations for negative while the middle and medial frontal gyrus showed higher activations for neutral and finally, the inferior frontal gyrus showed higher activations for positive valence. Besides replicating the previous knowledge of frontal activations in response to context congruity, the current study provides further evidence for the sensitivity of the frontal lobe to the valence associated with the incongruent stimuli.
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Affiliation(s)
- Angel Anna Zacharia
- Stress and Cognitive Electroimaging Lab, Department of Physiology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Navdeep Ahuja
- Stress and Cognitive Electroimaging Lab, Department of Physiology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Simran Kaur
- Stress and Cognitive Electroimaging Lab, Department of Physiology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Ratna Sharma
- Stress and Cognitive Electroimaging Lab, Department of Physiology, All India Institute of Medical Sciences, New Delhi 110029, India.
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22
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Carter O, van Swinderen B, Leopold DA, Collin S, Maier A. Perceptual rivalry across animal species. J Comp Neurol 2020; 528:3123-3133. [PMID: 32361986 PMCID: PMC7541519 DOI: 10.1002/cne.24939] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/18/2020] [Accepted: 04/20/2020] [Indexed: 01/10/2023]
Abstract
This review in memoriam of Jack Pettigrew provides an overview of past and current research into the phenomenon of multistable perception across multiple animal species. Multistable perception is characterized by two or more perceptual interpretations spontaneously alternating, or rivaling, when animals are exposed to stimuli with inherent sensory ambiguity. There is a wide array of ambiguous stimuli across sensory modalities, ranging from the configural changes observed in simple line drawings, such as the famous Necker cube, to the alternating perception of entire visual scenes that can be instigated by interocular conflict. The latter phenomenon, called binocular rivalry, in particular caught the attention of the late Jack Pettigrew, who combined his interest in the neuronal basis of perception with a unique comparative biological approach that considered ambiguous sensation as a fundamental problem of sensory systems that has shaped the brain throughout evolution. Here, we examine the research findings on visual perceptual alternation and suppression in a wide variety of species including insects, fish, reptiles, and primates. We highlight several interesting commonalities across species and behavioral indicators of perceptual alternation. In addition, we show how the comparative approach provides new avenues for understanding how the brain suppresses opposing sensory signals and generates alternations in perceptual dominance.
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Affiliation(s)
- Olivia Carter
- Melbourne School of Psychological Sciences, University of Melbourne, Parkville, VIC, AUS
| | | | | | - Shaun Collin
- School of Life Sciences, La Trobe University, Melbourne, VIC, AUS
| | - Alex Maier
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
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23
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Bareham CA, Oxner M, Gastrell T, Carmel D. Beyond the neural correlates of consciousness: using brain stimulation to elucidate causal mechanisms underlying conscious states and contents. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1840405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Corinne A. Bareham
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - Matt Oxner
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - Tim Gastrell
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - David Carmel
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
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24
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Intracranial Recordings Reveal Unique Shape and Timing of Responses in Human Visual Cortex during Illusory Visual Events. Curr Biol 2020; 30:3089-3100.e4. [PMID: 32619489 DOI: 10.1016/j.cub.2020.05.082] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 05/01/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023]
Abstract
During binocular rivalry, perception spontaneously changes without any alteration to the visual stimulus. What neural events bring about this illusion that a constant stimulus is changing? We recorded from intracranial electrodes placed on the occipital and posterior temporal cortex of two patients with epilepsy while they experienced illusory changes of a face-house binocular-rivalry stimulus or observed a control stimulus that physically changed. We performed within-patient comparisons of broadband high-frequency responses, focusing on single epochs recorded along the ventral processing stream. We found transient face- and house-selective responses localized to the same electrodes for illusory and physical changes, but the temporal characteristics of these responses markedly differed. In comparison with physical changes, responses to illusory changes were longer lasting, in particular exhibiting a characteristic slow rise. Furthermore, the temporal order of responses across the visual hierarchy was reversed for illusory as compared to physical changes: for illusory changes, higher order fusiform and parahippocampal regions responded before lower order occipital regions. Our tentative interpretation of these findings is that two stages underlie the initiation of illusory changes: a destabilization stage in which activity associated with the impending change gradually accumulates across the visual hierarchy, ultimately graduating in a top-down cascade of activity that may stabilize the new perceptual interpretation of the stimulus.
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25
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Darki F, Rankin J. Methods to assess binocular rivalry with periodic stimuli. JOURNAL OF MATHEMATICAL NEUROSCIENCE 2020; 10:10. [PMID: 32542516 PMCID: PMC7295892 DOI: 10.1186/s13408-020-00087-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 06/04/2020] [Indexed: 05/29/2023]
Abstract
Binocular rivalry occurs when the two eyes are presented with incompatible stimuli and perception alternates between these two stimuli. This phenomenon has been investigated in two types of experiments: (1) Traditional experiments where the stimulus is fixed, (2) eye-swap experiments in which the stimulus periodically swaps between eyes many times per second (Logothetis et al. in Nature 380(6575):621-624, 1996). In spite of the rapid swapping between eyes, perception can be stable for many seconds with specific stimulus parameter configurations. Wilson introduced a two-stage, hierarchical model to explain both types of experiments (Wilson in Proc. Natl. Acad. Sci. 100(24):14499-14503, 2003). Wilson's model and other rivalry models have been only studied with bifurcation analysis for fixed inputs and different types of dynamical behavior that can occur with periodically forcing inputs have not been investigated. Here we report (1) a more complete description of the complex dynamics in the unforced Wilson model, (2) a bifurcation analysis with periodic forcing. Previously, bifurcation analysis of the Wilson model with fixed inputs has revealed three main types of dynamical behaviors: Winner-takes-all (WTA), Rivalry oscillations (RIV), Simultaneous activity (SIM). Our results have revealed richer dynamics including mixed-mode oscillations (MMOs) and a period-doubling cascade, which corresponds to low-amplitude WTA (LAWTA) oscillations. On the other hand, studying rivalry models with numerical continuation shows that periodic forcing with high frequency (e.g. 18 Hz, known as flicker) modulates the three main types of behaviors that occur with fixed inputs with forcing frequency (WTA-Mod, RIV-Mod, SIM-Mod). However, dynamical behavior will be different with low frequency periodic forcing (around 1.5 Hz, so-called swap). In addition to WTA-Mod and SIM-Mod, cycle skipping, multi-cycle skipping and chaotic dynamics are found. This research provides a framework for either assessing binocular rivalry models to check consistency with empirical results, or for better understanding neural dynamics and mechanisms necessary to implement a minimal binocular rivalry model.
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Affiliation(s)
- Farzaneh Darki
- Department of Mathematics, College of Engineering, Mathematics & Physical Sciences, University of Exeter, Exeter, UK.
| | - James Rankin
- Department of Mathematics, College of Engineering, Mathematics & Physical Sciences, University of Exeter, Exeter, UK
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26
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Neural representations of perceptual color experience in the human ventral visual pathway. Proc Natl Acad Sci U S A 2020; 117:13145-13150. [PMID: 32457156 DOI: 10.1073/pnas.1911041117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Color is a perceptual construct that arises from neural processing in hierarchically organized cortical visual areas. Previous research, however, often failed to distinguish between neural responses driven by stimulus chromaticity versus perceptual color experience. An unsolved question is whether the neural responses at each stage of cortical processing represent a physical stimulus or a color we see. The present study dissociated the perceptual domain of color experience from the physical domain of chromatic stimulation at each stage of cortical processing by using a switch rivalry paradigm that caused the color percept to vary over time without changing the retinal stimulation. Using functional MRI (fMRI) and a model-based encoding approach, we found that neural representations in higher visual areas, such as V4 and VO1, corresponded to the perceived color, whereas responses in early visual areas V1 and V2 were modulated by the chromatic light stimulus rather than color perception. Our findings support a transition in the ascending human ventral visual pathway, from a representation of the chromatic stimulus at the retina in early visual areas to responses that correspond to perceptually experienced colors in higher visual areas.
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27
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Wang Z, Dai W, McLaughlin DW. Ring models of binocular rivalry and fusion. J Comput Neurosci 2020; 48:193-211. [PMID: 32363561 DOI: 10.1007/s10827-020-00744-7] [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: 08/05/2019] [Revised: 03/19/2020] [Accepted: 03/24/2020] [Indexed: 11/27/2022]
Abstract
When similar visual stimuli are presented binocularly to both eyes, one perceives a fused single image. However, when the two stimuli are distinct, one does not perceive a single image; instead, one perceives binocular rivalry. That is, one perceives one of the stimulated patterns for a few seconds, then the other for few seconds, and so on - with random transitions between the two percepts. Most theoretical studies focus on rivalry, with few considering the coexistence of fusion and rivalry. Here we develop three distinct computational neuronal network models which capture binocular rivalry with realistic stochastic properties, fusion, and the hysteretic transition between. Each is a conductance-based point neuron model, which is multi-layer with two ocular dominance columns (L & R) and with an idealized "ring" architecture where the orientation preference of each neuron labels its location on a ring. In each model, the primary mechanism initiating binocular rivalry is cross-column inhibition, with firing rate adaptation governing the temporal properties of the transitions between percepts. Under stimulation by similar visual patterns, each of three models uses its own mechanism to overcome cross-column inhibition, and thus to prevent rivalry and allow the fusion of similar images: The first model uses cross-column feedforward inhibition from the opposite eye to "shut off" the cross-column feedback inhibition; the second model "turns on" a second layer of monocular neurons as a parallel pathway to the binocular neurons, rivaling out of phase with the first layer, and together these two pathways represent fusion; and the third model uses cross-column excitation to overcome the cross-column inhibition and enable fusion. Thus, each of the idealized ring models depends upon a different mechanism for fusion that might emerge as an underlying mechanism present in real visual cortex.
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Affiliation(s)
- Ziqi Wang
- Integrated Program in Neuroscience, McGill University, 3801 Rue Université, Montréal, QC, H3A 2B4, Canada
| | - Wei Dai
- New York University - Courant Institute of Mathematical Science, 251 Mercer Street, New York, NY, 10012, USA
| | - David W McLaughlin
- New York University - Courant Institute of Mathematical Science, 251 Mercer Street, New York, NY, 10012, USA. .,New York University - Tandon School of Engineering, 6 Metro Tech Center, Brooklyn, NY, 11201, USA. .,New York University Shanghai, 1555 Century Ave, Pudong, Shanghai, 200122, China. .,Neuroscience Institute at NYU Langone Medical Center, Science Building, 435 East 30th Street, New York, NY, 10016, USA.
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28
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A hierarchical model of perceptual multistability involving interocular grouping. J Comput Neurosci 2020; 48:177-192. [PMID: 32338341 DOI: 10.1007/s10827-020-00743-8] [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: 10/18/2019] [Revised: 02/04/2020] [Accepted: 02/11/2020] [Indexed: 10/24/2022]
Abstract
Ambiguous visual images can generate dynamic and stochastic switches in perceptual interpretation known as perceptual rivalry. Such dynamics have primarily been studied in the context of rivalry between two percepts, but there is growing interest in the neural mechanisms that drive rivalry between more than two percepts. In recent experiments, we showed that split images presented to each eye lead to subjects perceiving four stochastically alternating percepts (Jacot-Guillarmod et al. Vision research, 133, 37-46, 2017): two single eye images and two interocularly grouped images. Here we propose a hierarchical neural network model that exhibits dynamics consistent with our experimental observations. The model consists of two levels, with the first representing monocular activity, and the second representing activity in higher visual areas. The model produces stochastically switching solutions, whose dependence on task parameters is consistent with four generalized Levelt Propositions, and with experiments. Moreover, dynamics restricted to invariant subspaces of the model demonstrate simpler forms of bistable rivalry. Thus, our hierarchical model generalizes past, validated models of binocular rivalry. This neuromechanistic model also allows us to probe the roles of interactions between populations at the network level. Generalized Levelt's Propositions hold as long as feedback from the higher to lower visual areas is weak, and the adaptation and mutual inhibition at the higher level is not too strong. Our results suggest constraints on the architecture of the visual system and show that complex visual stimuli can be used in perceptual rivalry experiments to develop more detailed mechanistic models of perceptual processing.
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29
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Brascamp JW, Qian CS, Hambrick DZ, Becker MW. Individual differences point to two separate processes involved in the resolution of binocular rivalry. J Vis 2020; 19:15. [PMID: 31622474 DOI: 10.1167/19.12.15] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although binocular rivalry is different from other perceptually bistable phenomena in requiring interocular conflict, it also shares numerous features with those phenomena. This raises the question of whether, and to what extent, the neural bases of binocular rivalry and other bistable phenomena overlap. Here we examine this question using an individual-differences approach. In a first experiment, observers reported perception during four binocular rivalry tasks that differed in the features and retinal locations of the stimuli used. Perceptual dominance durations were highly correlated when compared between stimuli that differed in location only. Correlations were substantially weaker, however, when comparing stimuli comprised of different features. Thus, individual differences in binocular-rivalry perception partly reflect a feature-specific factor that is not shared among all variants of binocular rivalry. Our second experiment again included several binocular rivalry variants, but also a different form of bistability: moving plaid rivalry. Correlations in dominance durations between binocular rivalry variants that differed in feature content were again modest. Moreover, and surprisingly, correlations between binocular rivalry and moving plaid rivalry were of similar magnitude. This indicates a second, more general, factor underlying individual differences in binocular rivalry perception: one that is shared across binocular rivalry and moving plaid rivalry. We propose that the first, feature-specific factor corresponds to feature-tuned mechanisms involved in the treatment of interocular conflict, whereas the second, general factor corresponds to mechanisms involved in representing surfaces. These latter mechanisms would operate at a binocular level and be central to both binocular rivalry and other forms of bistability.
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Affiliation(s)
- Jan W Brascamp
- Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - Cheng Stella Qian
- Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - David Z Hambrick
- Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - Mark W Becker
- Department of Psychology, Michigan State University, East Lansing, MI, USA
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30
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Gayet S, Guggenmos M, Christophel TB, Haynes JD, Paffen CLE, Sterzer P, Van der Stigchel S. No evidence for mnemonic modulation of interocularly suppressed visual input. Neuroimage 2020; 215:116801. [PMID: 32276069 DOI: 10.1016/j.neuroimage.2020.116801] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/04/2020] [Accepted: 03/24/2020] [Indexed: 01/24/2023] Open
Abstract
Visual working memory (VWM) allows for keeping visual information available for upcoming goal-directed behavior, while new visual input is processed concurrently. Interactions between the mnemonic and perceptual systems cause VWM to affect the processing of visual input in a content-specific manner: visual input that is initially suppressed from consciousness is detected faster when it matches rather than mismatches the content of VWM. It is currently under debate whether such mnemonic influences on perception occur prior to or after conscious access. To address this issue, we investigated whether VWM content modulates the neural response to visual input that remains suppressed from consciousness. We measured fMRI responses to interocularly suppressed stimuli in 20 human participants performing a delayed match-to-sample task: Participants were retro-cued to memorize one of two geometrical shapes for subsequent recognition. During retention, an interocularly suppressed peripheral stimulus (the probe) was briefly presented, which was either of the cued (memorized) or uncued (not memorized) shape category. We found no evidence that VWM content modulated the neural response to the probe. Substantial evidence for the absence of this modulation was found despite leveraging a highly liberal analysis approach: (1) selecting regions of interest that were particularly prone to detecting said modulation, and (2) using directional Bayesian tests favoring the presence of the hypothesized modulation. We did observe faster detection of memory-matching compared to memory-mismatching probes in a behavioral control experiment, thus validating the stimulus set. We conclude that VWM impacts the processing of visual input only once suppression is mostly alleviated.
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Affiliation(s)
- Surya Gayet
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands.
| | - Matthias Guggenmos
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin, Berlin, Germany
| | - Thomas B Christophel
- Max-Planck Institute for Human Development, Berlin, Germany; Berlin Center for Advanced Neuroimaging, Charité Universitätsmedizin, Berlin, Germany
| | - John-Dylan Haynes
- Berlin Center for Advanced Neuroimaging, Charité Universitätsmedizin, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany; Berlin School of Mind and Brain, Humboldt Universität, Berlin, Germany
| | - Chris L E Paffen
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Philipp Sterzer
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin, Berlin, Germany; Berlin Center for Advanced Neuroimaging, Charité Universitätsmedizin, Berlin, Germany; Berlin School of Mind and Brain, Humboldt Universität, Berlin, Germany
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31
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Little DF, Snyder JS, Elhilali M. Ensemble modeling of auditory streaming reveals potential sources of bistability across the perceptual hierarchy. PLoS Comput Biol 2020; 16:e1007746. [PMID: 32275706 PMCID: PMC7185718 DOI: 10.1371/journal.pcbi.1007746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/27/2020] [Accepted: 02/25/2020] [Indexed: 11/19/2022] Open
Abstract
Perceptual bistability-the spontaneous, irregular fluctuation of perception between two interpretations of a stimulus-occurs when observing a large variety of ambiguous stimulus configurations. This phenomenon has the potential to serve as a tool for, among other things, understanding how function varies across individuals due to the large individual differences that manifest during perceptual bistability. Yet it remains difficult to interpret the functional processes at work, without knowing where bistability arises during perception. In this study we explore the hypothesis that bistability originates from multiple sources distributed across the perceptual hierarchy. We develop a hierarchical model of auditory processing comprised of three distinct levels: a Peripheral, tonotopic analysis, a Central analysis computing features found more centrally in the auditory system, and an Object analysis, where sounds are segmented into different streams. We model bistable perception within this system by applying adaptation, inhibition and noise into one or all of the three levels of the hierarchy. We evaluate a large ensemble of variations of this hierarchical model, where each model has a different configuration of adaptation, inhibition and noise. This approach avoids the assumption that a single configuration must be invoked to explain the data. Each model is evaluated based on its ability to replicate two hallmarks of bistability during auditory streaming: the selectivity of bistability to specific stimulus configurations, and the characteristic log-normal pattern of perceptual switches. Consistent with a distributed origin, a broad range of model parameters across this hierarchy lead to a plausible form of perceptual bistability.
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Affiliation(s)
- David F. Little
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Joel S. Snyder
- Department of Psychology, University of Nevada, Las Vegas; Las Vegas, Nevada, United States of America
| | - Mounya Elhilali
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
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32
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Loued-Khenissi L, Pfeuffer A, Einhäuser W, Preuschoff K. Anterior insula reflects surprise in value-based decision-making and perception. Neuroimage 2020; 210:116549. [DOI: 10.1016/j.neuroimage.2020.116549] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 12/20/2019] [Accepted: 01/14/2020] [Indexed: 11/30/2022] Open
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33
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Löffler A, Haggard P, Bode S. Decoding Changes of Mind in Voluntary Action-Dynamics of Intentional Choice Representations. Cereb Cortex 2020; 30:1199-1212. [PMID: 31504263 DOI: 10.1093/cercor/bhz160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 05/01/2019] [Accepted: 06/24/2019] [Indexed: 01/08/2023] Open
Abstract
Voluntary actions rely on appropriate flexibility of intentions. Usually, we should pursue our goals, but sometimes we should change goals if they become too costly to achieve. Using functional magnetic resonance imaging, we investigated the neural dynamics underlying the capacity to change one's mind based on new information after action onset. Multivariate pattern analyses revealed that in visual areas, neural representations of intentional choice between 2 visual stimuli were unchanged by additional decision-relevant information. However, in fronto-parietal cortex, representations changed dynamically as decisions evolved. Precuneus, angular gyrus, and dorsolateral prefrontal cortex encoded new externally cued rewards/costs that guided subsequent changes of mind. Activity in medial frontal cortex predicted changes of mind when participants detached from externally cued evidence, suggesting a role in endogenous decision updates. Finally, trials with changes of mind were associated with an increase in functional connectivity between fronto-parietal areas, allowing for integration of various endogenous and exogenous decision components to generate a distributed consensus about whether to pursue or abandon an initial intention. In conclusion, local and global dynamics of choice representations in fronto-parietal cortex allow agents to maintain the balance between adapting to changing environments versus pursuing internal goals.
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Affiliation(s)
- Anne Löffler
- Zuckerman Mind Brain Behaviour Institute, Columbia University, New York, NY 10027, USA.,Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, UK.,Melbourne School of Psychological Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, UK
| | - Stefan Bode
- Melbourne School of Psychological Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.,Department of Psychology, University of Cologne, 50969 Cologne, Germany
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34
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Ooi TL, He ZJ. Sensory Eye Dominance: Relationship Between Eye and Brain. Eye Brain 2020; 12:25-31. [PMID: 32021530 PMCID: PMC6980844 DOI: 10.2147/eb.s176931] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/28/2019] [Indexed: 11/23/2022] Open
Abstract
Eye dominance refers to the preference to use one eye more than the fellow eye to accomplish a task. However, the dominant eye revealed can be task dependent especially when the tasks are as diverse as instructing the observer to sight a target through a ring, or to report which half-image is perceived more of during binocular rivalry stimulation. Conventionally, the former task is said to reveal motor eye dominance while the latter task reveals sensory eye dominance. While the consensus is that the motor and sensory-dominant eye could be different in some observers, the reason for it is still unclear and has not been much researched. This review mainly focuses on advances made in recent studies of sensory eye dominance. It reviews studies conducted to quantify and relate sensory eye dominance to other visual functions, in particular to stereopsis, as well as studies conducted to explore its plasticity. It is recognized that sensory eye dominance in observers with clinically normal vision shares some similarity with amblyopia at least at the behavioral level, in that both exhibit an imbalance of interocular inhibition. Furthermore, sensory eye dominance is probably manifested at multiple sites along the visual pathway, perhaps including the level of ocular dominance columns. But future studies with high-resolution brain imaging approaches are required to confirm this speculation in the human visual system.
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Affiliation(s)
- Teng Leng Ooi
- College of Optometry, The Ohio State University, Columbus, OH, USA
| | - Zijiang J He
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY, USA
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35
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Cox MA, Dougherty K, Westerberg JA, Schall MS, Maier A. Temporal dynamics of binocular integration in primary visual cortex. J Vis 2019; 19:13. [PMID: 31622471 PMCID: PMC6797477 DOI: 10.1167/19.12.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Whenever we open our eyes, our brain quickly integrates the two eyes' perspectives into a combined view. This process of binocular integration happens so rapidly that even incompatible stimuli are briefly fused before one eye's view is suppressed in favor of the other (binocular rivalry). The neuronal basis for this brief period of fusion during incompatible binocular stimulation is unclear. Neuroanatomically, the eyes provide two largely separate streams of information that are integrated into a binocular response by the primary visual cortex (V1). However, the temporal dynamics underlying the formation of this binocular response are largely unknown. To address this question, we examined the temporal profile of binocular responses in V1 of fixating monkeys. We found that V1 processes binocular stimuli in a dynamic sequence that comprises at least two distinct temporal phases. An initial transient phase is characterized by enhanced spiking responses for both compatible and incompatible binocular stimuli compared to monocular stimulation. This transient is followed by a sustained response that differed markedly between congruent and incongruent binocular stimulation. Specifically, incompatible binocular stimulation resulted in overall response reduction relative to monocular stimulation (binocular suppression). In contrast, responses to compatible stimuli were either suppressed or enhanced (binocular facilitation) depending on the neurons' ocularity (selectivity for one eye over the other) and laminar location. These results suggest that binocular integration in V1 occurs in at least two sequential steps that comprise initial additive combination of the two eyes' signals followed by widespread differentiation between binocular concordance and discordance.
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Affiliation(s)
- Michele A Cox
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Cognitive and Integrative Neuroscience, Vanderbilt University, Nashville, TN, USA
| | - Kacie Dougherty
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Cognitive and Integrative Neuroscience, Vanderbilt University, Nashville, TN, USA
| | - Jacob A Westerberg
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Cognitive and Integrative Neuroscience, Vanderbilt University, Nashville, TN, USA
| | - Michelle S Schall
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Cognitive and Integrative Neuroscience, Vanderbilt University, Nashville, TN, USA
| | - Alexander Maier
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Cognitive and Integrative Neuroscience, Vanderbilt University, Nashville, TN, USA
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36
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Parr T, Corcoran AW, Friston KJ, Hohwy J. Perceptual awareness and active inference. Neurosci Conscious 2019; 2019:niz012. [PMID: 31528360 PMCID: PMC6734140 DOI: 10.1093/nc/niz012] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/24/2019] [Accepted: 07/28/2019] [Indexed: 12/16/2022] Open
Abstract
Perceptual awareness depends upon the way in which we engage with our sensorium. This notion is central to active inference, a theoretical framework that treats perception and action as inferential processes. This variational perspective on cognition formalizes the notion of perception as hypothesis testing and treats actions as experiments that are designed (in part) to gather evidence for or against alternative hypotheses. The common treatment of perception and action affords a useful interpretation of certain perceptual phenomena whose active component is often not acknowledged. In this article, we start by considering Troxler fading - the dissipation of a peripheral percept during maintenance of fixation, and its recovery during free (saccadic) exploration. This offers an important example of the failure to maintain a percept without actively interrogating a visual scene. We argue that this may be understood in terms of the accumulation of uncertainty about a hypothesized stimulus when free exploration is disrupted by experimental instructions or pathology. Once we take this view, we can generalize the idea of using bodily (oculomotor) action to resolve uncertainty to include the use of mental (attentional) actions for the same purpose. This affords a useful way to think about binocular rivalry paradigms, in which perceptual changes need not be associated with an overt movement.
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Affiliation(s)
- Thomas Parr
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, Institute of Neurology, 12 Queen Square, London, UK
| | - Andrew W Corcoran
- Cognition & Philosophy Laboratory, Department of Philosophy, Monash University, Melbourne, Australia
| | - Karl J Friston
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, Institute of Neurology, 12 Queen Square, London, UK
| | - Jakob Hohwy
- Cognition & Philosophy Laboratory, Department of Philosophy, Monash University, Melbourne, Australia
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37
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Kim S, Kim J. Effects of Multimodal Association on Ambiguous Perception in Binocular Rivalry. Perception 2019; 48:796-819. [DOI: 10.1177/0301006619867023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
When two eyes view dissimilar images, an observer typically reports ambiguous perception called binocular rivalry where the subjective perception fluctuates between the two inputs. This perceptual instability is often comprised of exclusive dominance of each image and a transition state called piecemeal state where the two images are intermingled in patchwork manner. Herein, we investigated the effects of multimodal association of sensory congruent pair, arbitrary pair, and reverse pair on piecemeal state in order to see how each level of association affects the ambiguous perception during binocular rivalry. To induce the multisensory associations, we designed a matching task with audiovisual feedback where subjects were required to respond according to given pairing rules. We found that explicit audiovisual associations can substantially affect the piecemeal state during binocular rivalry and that this congruency effect that reduces the amount of visual ambiguity originates primarily from explicit audiovisual association training rather than common sensory features. Furthermore, when one information is associated with multiple information, recent and preexisting associations work collectively to influence the perceptual ambiguity during rivalry. Our findings show that learned multimodal association directly affects the temporal dynamics of ambiguous perception during binocular rivalry by modulating not only the exclusive dominance but also the piecemeal state in a systematic manner.
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Affiliation(s)
- Sungyong Kim
- Graduate School of Culture Technology, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jeounghoon Kim
- Graduate School of Culture Technology, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea; School of Humanities and Social Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
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38
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Bock EA, Fesi JD, Baillet S, Mendola JD. Tagged MEG measures binocular rivalry in a cortical network that predicts alternation rate. PLoS One 2019; 14:e0218529. [PMID: 31295259 PMCID: PMC6622468 DOI: 10.1371/journal.pone.0218529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 06/04/2019] [Indexed: 11/30/2022] Open
Abstract
Binocular rivalry (BR) is a dynamic visual illusion that provides insight into the cortical mechanisms of visual awareness, stimulus selection, and object identification. When dissimilar binocular images cannot be fused, perception switches every few seconds between the left and right eye images. The speed at which individuals switch between alternatives is a stable, partially heritable trait. In order to isolate the monocular and binocular processes that determine the speed of rivalry, we presented stimuli tagged with a different flicker frequency in each eye and applied stimulus-phase locked MEG source imaging. We hypothesized that the strength of the evoked fundamental or intermodulation frequencies would vary when comparing Fast and Slow Switchers. Ten subjects reported perceptual alternations, with mean dominance durations between 1.2–4.0 sec. During BR, event-related monocular input in V1, and broadly in higher-tier ventral temporal cortex, waxed and waned with the periods of left or right eye dominance/suppression. In addition, we show that Slow Switchers produce greater evoked intermodulation frequency responses in a cortical network composed of V1, lateral occipital, posterior STS, retrosplenial & superior parietal cortices. Importantly, these dominance durations were not predictable from the brain responses to either of the fundamental tagging frequencies in isolation, nor from any responses to a pattern rivalry control condition, or a non-rivalrous control. The novel cortical network isolated, which overlaps with the default-mode network, may contain neurons that compute the level of endogenous monocular difference, and monitor accumulation of this conflict over extended periods of time. These findings are the first to relate the speed of rivalry across observers to the ‘efficient coding’ theory of computing binocular differences that may apply to binocular vision generally.
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Affiliation(s)
- Elizabeth A. Bock
- Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Jeremy D. Fesi
- Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Sylvain Baillet
- Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Janine D. Mendola
- Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
- * E-mail:
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39
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Jiang Q, Shao F, Gao W, Chen Z, Jiang G, Ho YS. Unified No-Reference Quality Assessment of Singly and Multiply Distorted Stereoscopic Images. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2019; 28:1866-1881. [PMID: 30452360 DOI: 10.1109/tip.2018.2881828] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A challenging problem in the no-reference quality assessment of multiply distorted stereoscopic images (MDSIs) is to simulate the monocular and binocular visual properties under a mixed type of distortions. Due to the joint effects of multiple distortions in MDSIs, the underlying monocular and binocular visual mechanisms have different manifestations with those of singly distorted stereoscopic images (SDSIs). This paper presents a unified no-reference quality evaluator for SDSIs and MDSIs by learning monocular and binocular local visual primitives (MB-LVPs). The main idea is to learn MB-LVPs to characterize the local receptive field properties of the visual cortex in response to SDSIs and MDSIs. Furthermore, we also consider that the learning of primitives should be performed in a task-driven manner. For this, two penalty terms including reconstruction error and quality inconsistency are jointly minimized within a supervised dictionary learning framework, generating a set of quality-oriented MB-LVPs for each single and multiple distortion modality. Given an input stereoscopic image, feature encoding is performed using the learned MB-LVPs as codebooks, resulting in the corresponding monocular and binocular responses. Finally, responses across all the modalities are fused with probabilistic weights which are determined by the modality-specific sparse reconstruction errors, yielding the final monocular and binocular features for quality regression. The superiority of our method has been verified on several SDSI and MDSI databases.
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40
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Bahmani H, Li Q, Logothetis NK, Keliris GA. Responses of Neurons in Lateral Intraparietal Area Depend on Stimulus-Associated Reward During Binocular Flash Suppression. Front Syst Neurosci 2019; 13:9. [PMID: 30914928 PMCID: PMC6422913 DOI: 10.3389/fnsys.2019.00009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 02/25/2019] [Indexed: 11/13/2022] Open
Abstract
Discovering neural correlates of subjective perception and dissociating them from sensory input has fascinated neuroscientists for a long time. Bistable and multistable perception phenomena have exhibited great experimental potential to address this question. Here, we performed electrophysiological recordings from single neurons in lateral intraparietal area (LIP) of rhesus macaques during stimulus and perceptual transitions induced by binocular flash suppression (BFS). LIP neurons demonstrated transient bursts of activity after stimulus presentation and stimulus or perceptual switches but only a minority of cells demonstrated stimulus and perceptual selectivity. To enhance LIP neural selectivity, we performed a second experiment in which the competing stimuli were associated with asymmetric rewards. We found that transient and sustained activities substantially increased while the proportion of stimulus selective neurons remained approximately the same, albeit with increased selectivity magnitude. In addition, we observed mild increases in the proportion of perceptually selective neurons which also showed increase magnitude of selectivity. Importantly, the increased selectivity of cells after the reward manipulation was not directly reflecting the reward size per se but an enhancement in stimulus differentiation. Based on our results, we conjecture that LIP contributes to perceptual transitions and serves a modulatory role in perceptual selection taking into account the stimulus behavioral value.
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Affiliation(s)
- Hamed Bahmani
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Bernstein Center for Computational Neuroscience, Tuebingen, Germany
| | - Qinglin Li
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Bernstein Center for Computational Neuroscience, Tuebingen, Germany
| | - Nikos K Logothetis
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, United Kingdom
| | - Georgios A Keliris
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Bernstein Center for Computational Neuroscience, Tuebingen, Germany.,Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
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41
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van der Groen O, Mattingley JB, Wenderoth N. Altering brain dynamics with transcranial random noise stimulation. Sci Rep 2019; 9:4029. [PMID: 30858404 PMCID: PMC6411772 DOI: 10.1038/s41598-019-40335-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/14/2019] [Indexed: 11/26/2022] Open
Abstract
Random noise can enhance the detectability of weak signals in nonlinear systems, a phenomenon known as stochastic resonance (SR). This concept is not only applicable to single threshold systems but can also be applied to dynamical systems with multiple attractor states, such as observed during the phenomenon of binocular rivalry. Binocular rivalry can be characterized by marginally stable attractor states between which the brain switches in a spontaneous, stochastic manner. Here we used a computational model to predict the effect of noise on perceptual dominance durations. Subsequently we compared the model prediction to a series of experiments where we measured binocular rivalry dynamics when noise (zero-mean Gaussian random noise) was added either to the visual stimulus (Exp. 1) or directly to the visual cortex (Exp. 2) by applying transcranial Random Noise Stimulation (tRNS 1 mA, 100–640 Hz zero -mean Gaussian random noise). We found that adding noise significantly reduced the mixed percept duration (Exp. 1 and Exp. 2). Our results are the first to demonstrate that both central and peripheral noise can influence state-switching dynamics of binocular rivalry under specific conditions (e.g. low visual contrast stimuli), in line with a SR-mechanism.
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Affiliation(s)
- Onno van der Groen
- Neural Control of Movement Laboratory, Health Sciences and Technology, ETH Zurich, Zurich, 8057, Switzerland. .,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, 6027, Australia.
| | - Jason B Mattingley
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland, 4072, Australia.,School of Psychology, The University of Queensland, St Lucia, Queensland, 4072, Australia.,Canadian Institute for Advanced Research (CIFAR), Toronto, Canada
| | - Nicole Wenderoth
- Neural Control of Movement Laboratory, Health Sciences and Technology, ETH Zurich, Zurich, 8057, Switzerland
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42
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Abstract
The mind and brain sciences began with consciousness as a central concern. But for much of the 20th century, ideological and methodological concerns relegated its empirical study to the margins. Since the 1990s, studying consciousness has regained a legitimacy and momentum befitting its status as the primary feature of our mental lives. Nowadays, consciousness science encompasses a rich interdisciplinary mixture drawing together philosophical, theoretical, computational, experimental, and clinical perspectives, with neuroscience its central discipline. Researchers have learned a great deal about the neural mechanisms underlying global states of consciousness, distinctions between conscious and unconscious perception, and self-consciousness. Further progress will depend on specifying closer explanatory mappings between (first-person subjective) phenomenological descriptions and (third-person objective) descriptions of (embodied and embedded) neuronal mechanisms. Such progress will help reframe our understanding of our place in nature and accelerate clinical approaches to a wide range of psychiatric and neurological disorders.
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Affiliation(s)
- Anil K Seth
- Sackler Centre for Consciousness Science and School of Engineering and Informatics, University of Sussex, Brighton, UK
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43
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Han C, He ZJ, Ooi TL. On Sensory Eye Dominance Revealed by Binocular Integrative and Binocular Competitive Stimuli. Invest Ophthalmol Vis Sci 2018; 59:5140-5148. [PMID: 30372739 PMCID: PMC6201702 DOI: 10.1167/iovs.18-24342] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 09/11/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose Two core processes underlie 3-D binocular vision. The first, a binocular combination/summation process, integrates similar feature signals from the two eye channels to form a binocular representation. The second, a binocular inhibitory process, suppresses interocular conflicting signals or falsely matched binocular representations to establish single vision. Having an intrinsic interocular imbalance within one or both processes can cause sensory eye dominance (SED), related to imbalances of combination (SEDcombo) and/or inhibition (SEDinhibition). While much has recently been revealed about SEDcombo and SEDinhibition, the relationship between them is still unknown. Methods We measured observers' foveal SEDcombo and SEDinhibition, respectively, with a pair of dichoptic horizontal sine wave gratings with different phases and binocular rivalry stimulus with vertical and horizontal gratings. We then measured horizontal and vertical monocular contrast thresholds using sinusoidal grating stimuli, and stereo thresholds using random-dot stereograms. Results There exists a strong correlation between SEDcombo and SEDinhibition. An observer's interocular difference in contrast threshold was not always consistent with his/her SEDcombo and SEDinhihition, suggesting a partial binocular origin for the underlying imbalances. We also found stereo thresholds significantly increased with the magnitudes of SEDcombo, as well as with the magnitude of SEDinhibition. Conclusions Our findings suggest a common origin for interocular imbalance in the two different binocular processes and that both types of sensory eye dominance are significant factors in impeding stereopsis.
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Affiliation(s)
- Chao Han
- College of Optometry, The Ohio State University, Columbus, Ohio, United States
| | - Zijiang J He
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, Kentucky, United States
| | - Teng Leng Ooi
- College of Optometry, The Ohio State University, Columbus, Ohio, United States
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Gruber LZ, Haruvi A, Basri R, Irani M. Perceptual Dominance in Brief Presentations of Mixed Images: Human Perception vs. Deep Neural Networks. Front Comput Neurosci 2018; 12:57. [PMID: 30087604 PMCID: PMC6066547 DOI: 10.3389/fncom.2018.00057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/03/2018] [Indexed: 11/23/2022] Open
Abstract
Visual perception involves continuously choosing the most prominent inputs while suppressing others. Neuroscientists induce visual competitions in various ways to study why and how the brain makes choices of what to perceive. Recently deep neural networks (DNNs) have been used as models of the ventral stream of the visual system, due to similarities in both accuracy and hierarchy of feature representation. In this study we created non-dynamic visual competitions for humans by briefly presenting mixtures of two images. We then tested feed-forward DNNs with similar mixtures and examined their behavior. We found that both humans and DNNs tend to perceive only one image when presented with a mixture of two. We revealed image parameters which predict this perceptual dominance and compared their predictability for the two visual systems. Our findings can be used to both improve DNNs as models, as well as potentially improve their performance by imitating biological behaviors.
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Affiliation(s)
- Liron Z Gruber
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Aia Haruvi
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Ronen Basri
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
| | - Michal Irani
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
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Hegdé J. Neural Mechanisms of High-Level Vision. Compr Physiol 2018; 8:903-953. [PMID: 29978891 DOI: 10.1002/cphy.c160035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The last three decades have seen major strides in our understanding of neural mechanisms of high-level vision, or visual cognition of the world around us. Vision has also served as a model system for the study of brain function. Several broad insights, as yet incomplete, have recently emerged. First, visual perception is best understood not as an end unto itself, but as a sensory process that subserves the animal's behavioral goal at hand. Visual perception is likely to be simply a side effect that reflects the readout of visual information processing that leads to behavior. Second, the brain is essentially a probabilistic computational system that produces behaviors by collectively evaluating, not necessarily consciously or always optimally, the available information about the outside world received from the senses, the behavioral goals, prior knowledge about the world, and possible risks and benefits of a given behavior. Vision plays a prominent role in the overall functioning of the brain providing the lion's share of information about the outside world. Third, the visual system does not function in isolation, but rather interacts actively and reciprocally with other brain systems, including other sensory faculties. Finally, various regions of the visual system process information not in a strict hierarchical manner, but as parts of various dynamic brain-wide networks, collectively referred to as the "connectome." Thus, a full understanding of vision will ultimately entail understanding, in granular, quantitative detail, various aspects of dynamic brain networks that use visual sensory information to produce behavior under real-world conditions. © 2017 American Physiological Society. Compr Physiol 8:903-953, 2018.
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Affiliation(s)
- Jay Hegdé
- Brain and Behavior Discovery Institute, Augusta University, Augusta, Georgia, USA.,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, USA.,Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.,The Graduate School, Augusta University, Augusta, Georgia, USA
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Breitmeyer BG, Tripathy SP, Brown JM. Can Contrast-Response Functions Indicate Visual Processing Levels? Vision (Basel) 2018; 2:vision2010014. [PMID: 31735878 PMCID: PMC6835543 DOI: 10.3390/vision2010014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 02/16/2018] [Accepted: 02/21/2018] [Indexed: 11/27/2022] Open
Abstract
Many visual effects are believed to be processed at several functional and anatomical levels of cortical processing. Determining if and how the levels contribute differentially to these effects is a leading problem in visual perception and visual neuroscience. We review and analyze a combination of extant psychophysical findings in the context of neurophysiological and brain-imaging results. Specifically using findings relating to visual illusions, crowding, and masking as exemplary cases, we develop a theoretical rationale for showing how relative levels of cortical processing contributing to these effects can already be deduced from the psychophysically determined functions relating respectively the illusory, crowding and masking strengths to the contrast of the illusion inducers, of the flankers producing the crowding, and of the mask. The wider implications of this rationale show how it can help to settle or clarify theoretical and interpretive inconsistencies and how it can further psychophysical, brain-recording and brain-imaging research geared to explore the relative functional and cortical levels at which conscious and unconscious processing of visual information occur. Our approach also allows us to make some specific predictions for future studies, whose results will provide empirical tests of its validity.
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Affiliation(s)
- Bruno G. Breitmeyer
- Department of Psychology, University of Houston, Houston, TX 77204, USA
- Correspondence: ; Tel.: +1-713-743-8570
| | - Srimant P. Tripathy
- School of Optometry & Visual Science, University of Bradford, Bradford BD7 1DP, UK
| | - James M. Brown
- Department of Psychology, University of Georgia, Athens, GA 30602, USA
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Chen Z, Zhou W, Li W. Blind Stereoscopic Video Quality Assessment: From Depth Perception to Overall Experience. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2018; 27:721-734. [PMID: 29185989 DOI: 10.1109/tip.2017.2766780] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Stereoscopic video quality assessment (SVQA) is a challenging problem. It has not been well investigated on how to measure depth perception quality independently under different distortion categories and degrees, especially exploit the depth perception to assist the overall quality assessment of 3D videos. In this paper, we propose a new depth perception quality metric (DPQM) and verify that it outperforms existing metrics on our published 3D video extension of High Efficiency Video Coding (3D-HEVC) video database. Furthermore, we validate its effectiveness by applying the crucial part of the DPQM to a novel blind stereoscopic video quality evaluator (BSVQE) for overall 3D video quality assessment. In the DPQM, we introduce the feature of auto-regressive prediction-based disparity entropy (ARDE) measurement and the feature of energy weighted video content measurement, which are inspired by the free-energy principle and the binocular vision mechanism. In the BSVQE, the binocular summation and difference operations are integrated together with the fusion natural scene statistic measurement and the ARDE measurement to reveal the key influence from texture and disparity. Experimental results on three stereoscopic video databases demonstrate that our method outperforms state-of-the-art SVQA algorithms for both symmetrically and asymmetrically distorted stereoscopic video pairs of various distortion types.
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Conflict-sensitive neurons gate interocular suppression in human visual cortex. Sci Rep 2018; 8:1239. [PMID: 29352155 PMCID: PMC5775389 DOI: 10.1038/s41598-018-19809-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/09/2018] [Indexed: 11/08/2022] Open
Abstract
Neural suppression plays an important role in cortical function, including sensory, memory, and motor systems. It remains, however, relatively poorly understood. A paradigmatic case arises when conflicting images are presented to the two eyes. These images can compete for awareness, and one is usually strongly suppressed. The mechanisms that resolve such interocular conflict remain unclear. Suppression could arise solely from “winner-take-all” competition between neurons responsive to each eye. Alternatively, suppression could also depend upon neurons detecting interocular conflict. Here, we provide physiological evidence in human visual cortex for the latter: suppression depends upon conflict-sensitive neurons. We recorded steady-state visual evoked potentials (SSVEP), and used the logic of selective adaptation. The amplitude of SSVEP responses at intermodulation frequencies strengthened as interocular conflict in the stimulus increased, suggesting the presence of neurons responsive to conflict. Critically, adaptation to conflict both reduced this SSVEP effect, and increased the amount of conflict needed to produce perceptual suppression. The simplest account of these results is that interocular-conflict-sensitive neurons exist in human cortex: adaptation likely reduced the responsiveness of these neurons which in turn raised the amount of conflict required to produce perceptual suppression. Similar mechanisms may be used to resolve other varieties of perceptual conflict.
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