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Deodato M, Ronconi L, Melcher D. Schizotypal traits and anomalous perceptual experiences are associated with greater visual temporal acuity. Schizophr Res 2024; 269:1-8. [PMID: 38703518 DOI: 10.1016/j.schres.2024.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/24/2024] [Accepted: 04/28/2024] [Indexed: 05/06/2024]
Abstract
One of the main tasks of the human visual system is to organize the temporal flow of visual events into meaningful patterns. It has been suggested that segregation/integration of continuous visual stimuli relies on temporal windows that are phase-locked to brain oscillations in the alpha frequency range (~10 Hz). From a behavioral point of view, the balance between integration and segregation is reflected in visual temporal acuity: the ability to perceive a small temporal gap between two identical stimuli. Disruption of this balance may lead to impairment of perceptual organization processes. Notably, schizophrenia, a condition characterized by unusual perceptual experiences, has been associated with abnormal temporal processing of sensory stimuli and aberrant oscillations. We asked a large cohort of healthy participants to complete an online version of the two-flash fusion task and two questionnaires for schizotypal personality traits to investigate individual differences in the temporal resolution of perception, particularly its relationship with anomalous perceptual experiences. We found that two-flash discrimination acuity declines with age and that schizotypal traits are associated with better performances. Although this association was strong for perceptual and cognitive subscales, we found that this result could not be attributed to response biases (e.g., hallucination of two flashes). While these results appear to contrast with findings of slower alpha rhythms and sensory processing in schizotypy, we propose that a faster visual rate could be the consequence of an oscillopathy or a disconnection between different sensory modalities and their physiological pacemaker.
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Affiliation(s)
- Michele Deodato
- Psychology Program, Division of Science, New York University Abu Dhabi, United Arab Emirates.
| | - Luca Ronconi
- School of Psychology, Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - David Melcher
- Psychology Program, Division of Science, New York University Abu Dhabi, United Arab Emirates; Center for Brain and Health, NYUAD Research Institute, New York University Abu Dhabi, United Arab Emirates
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2
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Zhu J, Zikopoulos B, Yazdanbakhsh A. A neural model of modified excitation/inhibition and feedback levels in schizophrenia. Front Psychiatry 2023; 14:1199690. [PMID: 37900297 PMCID: PMC10600455 DOI: 10.3389/fpsyt.2023.1199690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/20/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction The strength of certain visual illusions, including contrast-contrast and apparent motion, is weakened in individuals with schizophrenia. Such phenomena have been interpreted as the impaired integration of inhibitory and excitatory neural responses, and impaired top-down feedback mechanisms. Methods To investigate whether and how these factors influence the perceived contrast-contrast and apparent motion illusions in individuals with schizophrenia, we propose a two-layer network, with top-down feedback from layer 2 to layer 1 that can model visual receptive fields (RFs) and their inhibitory and excitatory subfields. Results Our neural model suggests that illusion perception changes in individuals with schizophrenia can be influenced by altered top-down mechanisms and the organization of the on-center off-surround receptive fields. Alteration of the RF inhibitory surround and/or the excitatory center can replicate the difference of illusion precepts between individuals with schizophrenia within certain clinical states and normal controls. The results show that the simulated top-down feedback modulation enlarges the difference of the model illusion representations, replicating the difference between the two groups. Discussion We propose that the heterogeneity of visual and in general sensory processing in certain clinical states of schizophrenia can be largely explained by the degree of top-down feedback reduction, emphasizing the critical role of top-down feedback in illusion perception, and to a lesser extent on the imbalance of excitation/inhibition. Our neural model provides a mechanistic explanation for the modulated visual percepts of contrast-contrast and apparent motion in schizophrenia with findings that can explain a broad range of visual perceptual observations in previous studies. The two-layer motif of the current model provides a general framework that can be tailored to investigate subcortico-cortical (such as thalamocortical) and cortico-cortical networks, bridging neurobiological changes in schizophrenia and perceptual processing.
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Affiliation(s)
- Jiating Zhu
- Program in Brain, Behavior & Cognition, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Arash Yazdanbakhsh
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Computational Neuroscience and Vision Laboratory, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
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Zhu J, Zikopoulos B, Yazdanbakhsh A. A neural model of modified excitation/inhibition and feedback levels in schizophrenia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538166. [PMID: 37162902 PMCID: PMC10168241 DOI: 10.1101/2023.04.24.538166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The strength of certain visual illusions is weakened in individuals with schizophrenia. Such phenomena have been interpreted as the impaired integration of inhibitory and excitatory neural responses, and impaired top-down feedback mechanisms. To investigate whether and how these factors influence the perceived illusions in individuals with schizophrenia, we propose a two-layer network that can model visual receptive fields (RFs), their inhibitory and excitatory subfields, and the top-down feedback. Our neural model suggests that illusion perception changes in individuals with schizophrenia can be influenced by altered top-down mechanisms and the organization of the on-center off-surround receptive fields. Alteration of the RF inhibitory surround and/or the excitatory center can replicate the difference of illusion precepts between individuals with schizophrenia and normal controls. The results show that the simulated top-down feedback modulation enlarges the difference of the model illusion representations, replicating the difference between the two groups. We propose that the heterogeneity of visual and in general sensory processing in schizophrenia can be largely explained by the degree of top-down feedback reduction, emphasizing the critical role of top-down feedback in illusion perception, and to a lesser extent on the imbalance of excitation/inhibition. Our neural model provides a mechanistic explanation for the modulated visual percepts in schizophrenia with findings that can explain a broad range of visual perceptual observations in previous studies. The two-layer motif of the current model provides a general framework that can be tailored to investigate subcortico-cortical (such as thalamocortical) and cortico-cortical networks, bridging neurobiological changes in schizophrenia and perceptual processing.
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Affiliation(s)
- Jiating Zhu
- Program in Brain, Behavior & Cognition, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Arash Yazdanbakhsh
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Computational Neuroscience and Vision Laboratory, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
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4
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Li Q, Xu X, Qian Y, Cai H, Zhao W, Zhu J, Yu Y. Resting-state brain functional alterations and their genetic mechanisms in drug-naive first-episode psychosis. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2023; 9:13. [PMID: 36841861 PMCID: PMC9968350 DOI: 10.1038/s41537-023-00338-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/07/2023] [Indexed: 02/27/2023]
Abstract
Extensive research has established the presence of resting-state brain functional damage in psychosis. However, the genetic mechanisms of such disease phenotype are yet to be unveiled. We investigated resting-state brain functional alterations in patients with drug-naive first-episode psychosis (DFP) by performing a neuroimaging meta-analysis of 8 original studies comprising 500 patients and 469 controls. Combined with the Allen Human Brain Atlas, we further conducted transcriptome-neuroimaging spatial correlations to identify genes whose expression levels were linked to brain functional alterations in DFP, followed by a range of gene functional characteristic analyses. Meta-analysis revealed a mixture of increased and decreased brain function in widespread areas including the default-mode, visual, motor, striatal, and cerebellar systems in DFP. Moreover, these brain functional alterations were spatially associated with the expression of 1662 genes, which were enriched for molecular functions, cellular components, and biological processes of the cerebral cortex, as well as psychiatric disorders including schizophrenia. Specific expression analyses demonstrated that these genes were specifically expressed in the brain tissue, in cortical neurons and immune cells, and during nearly all developmental periods. Concurrently, the genes could construct a protein-protein interaction network supported by hub genes and were linked to multiple behavioral domains including emotion, attention, perception, and motor. Our findings provide empirical evidence for the notion that brain functional damage in DFP involves a complex interaction of polygenes with various functional characteristics.
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Affiliation(s)
- Qian Li
- grid.459419.4Department of Radiology, Chaohu Hospital of Anhui Medical University, 238000 Hefei, China ,grid.412679.f0000 0004 1771 3402Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022 Hefei, China ,Research Center of Clinical Medical Imaging, Anhui Province, 230032 Hefei, China ,Anhui Provincial Institute of Translational Medicine, 230032 Hefei, China
| | - Xiaotao Xu
- grid.412679.f0000 0004 1771 3402Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022 Hefei, China ,Research Center of Clinical Medical Imaging, Anhui Province, 230032 Hefei, China ,Anhui Provincial Institute of Translational Medicine, 230032 Hefei, China
| | - Yinfeng Qian
- grid.412679.f0000 0004 1771 3402Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022 Hefei, China ,Research Center of Clinical Medical Imaging, Anhui Province, 230032 Hefei, China ,Anhui Provincial Institute of Translational Medicine, 230032 Hefei, China
| | - Huanhuan Cai
- grid.412679.f0000 0004 1771 3402Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022 Hefei, China ,Research Center of Clinical Medical Imaging, Anhui Province, 230032 Hefei, China ,Anhui Provincial Institute of Translational Medicine, 230032 Hefei, China
| | - Wenming Zhao
- grid.412679.f0000 0004 1771 3402Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022 Hefei, China ,Research Center of Clinical Medical Imaging, Anhui Province, 230032 Hefei, China ,Anhui Provincial Institute of Translational Medicine, 230032 Hefei, China
| | - Jiajia Zhu
- Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022, Hefei, China. .,Research Center of Clinical Medical Imaging, Anhui Province, 230032, Hefei, China. .,Anhui Provincial Institute of Translational Medicine, 230032, Hefei, China.
| | - Yongqiang Yu
- Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 230022, Hefei, China. .,Research Center of Clinical Medical Imaging, Anhui Province, 230032, Hefei, China. .,Anhui Provincial Institute of Translational Medicine, 230032, Hefei, China.
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5
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Zouraraki C, Kyriklaki A, Economou E, Giakoumaki SG. The moderating role of early traumatic experiences on the association of schizotypal traits with visual perception. Scand J Psychol 2023; 64:10-20. [PMID: 35833570 DOI: 10.1111/sjop.12859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/11/2022] [Accepted: 06/24/2022] [Indexed: 01/11/2023]
Abstract
The findings on the association of schizotypal traits with the perception of visual illusions are scarce and inconsistent and have not taken into consideration potential effects of childhood traumatic experiences, a risk factor for schizophrenia-spectrum conditions. Thus, the present study addressed the question of potential moderating effects of early traumatic experiences on the association between different aspects of schizotypal traits with the perception of the Müller-Lyer and Navon's Hierarchical Letters (NHL) illusions. The study revealed that (a) increased suspiciousness was associated with increased liability to the Müller-Lyer illusion, when the exposure to traumatic events was high, whereas the opposite pattern was true when the exposure to traumatic events was low; (b) negative schizotypy was associated with more accurate global perception, and high disorganized schizotypy was associated with superior accuracy when target letters were present during the NHL illusion, when early traumatic experiences were at lower levels; and (c) high negative, disorganized, and total schizotypy were associated with lower accuracy when target letters were present in the NHL paradigm, when early traumatic experiences were at higher levels. The findings of the study suggest that early traumatic events differentially moderate the relationship between various aspects of schizotypal traits and visual perceptual processing.
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Affiliation(s)
- Chrysoula Zouraraki
- Laboratory of Neuropsychology, Department of Psychology, University of Crete, Rethymno, Crete, Greece.,University of Crete Research Center for the Humanities, The Social and Educational Sciences (UCRC), University of Crete, Rethymno, Crete, Greece
| | - Andriani Kyriklaki
- Department of Social Medicine, School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Elias Economou
- Laboratory of Experimental Psychology, Department of Psychology, University of Crete, Rethymno, Crete, Greece
| | - Stella G Giakoumaki
- Laboratory of Neuropsychology, Department of Psychology, University of Crete, Rethymno, Crete, Greece.,University of Crete Research Center for the Humanities, The Social and Educational Sciences (UCRC), University of Crete, Rethymno, Crete, Greece
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6
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Costa ALL, Costa DL, Pessoa VF, Caixeta FV, Maior RS. Systematic review of visual illusions in schizophrenia. Schizophr Res 2023; 252:13-22. [PMID: 36610221 DOI: 10.1016/j.schres.2022.12.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/06/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
Visual illusions have long been used as tools to investigate sensory-perceptual deficits in schizophrenia. Recent conflicting accounts have called into question the assumption of abnormal illusion perception in patients and, therefore, the validity of this approach. Here, we present a systematic review of the current evidence regarding visual illusion perception abnormalities in patients with schizophrenia. Relevant publications were identified by a systematic search of PubMed, Literatura LILACS, PsycINFO, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), IBECS, BIOSIS, and Web of Science. Forty-five studies were selected which included illusions classified as 'Motion illusions', 'Geometric-optical illusions', 'Illusory contours', 'Depth inversion illusion', and 'Non-specific'. There is concordant evidence of abnormal processing of illusions in patients for most categories, especially in facial Depth Inversion and Müller-Lyer illusions. There were significant methodological disparities and shortcomings, but risk of bias was overall low for individual studies. The usefulness of visual illusions as tools in clinical settings as well as in basic research may be contingent on significant methodological refinements.
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Affiliation(s)
- Ana Luísa Lamounier Costa
- Department of Physiological Sciences, Institute of Biology, University of Brasilia, 70910-900 Brasilia, DF, Brazil
| | - Dorcas Lamounier Costa
- Maternal and Childhood Department, Federal University of Piauí, 64049-550 Teresina, PI, Brazil; Intelligence Center for Emerging and Neglected Tropical Diseases (CIATEN), 64.001-450 Teresina, PI, Brazil
| | - Valdir Filgueiras Pessoa
- Department of Physiological Sciences, Institute of Biology, University of Brasilia, 70910-900 Brasilia, DF, Brazil
| | - Fábio Viegas Caixeta
- Department of Physiological Sciences, Institute of Biology, University of Brasilia, 70910-900 Brasilia, DF, Brazil
| | - Rafael S Maior
- Department of Physiological Sciences, Institute of Biology, University of Brasilia, 70910-900 Brasilia, DF, Brazil.
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7
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Born RT, Bencomo GM. Illusions, Delusions, and Your Backwards Bayesian Brain: A Biased Visual Perspective. BRAIN, BEHAVIOR AND EVOLUTION 2021; 95:272-285. [PMID: 33784667 PMCID: PMC8238803 DOI: 10.1159/000514859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/27/2021] [Indexed: 12/29/2022]
Abstract
The retinal image is insufficient for determining what is "out there," because many different real-world geometries could produce any given retinal image. Thus, the visual system must infer which external cause is most likely, given both the sensory data and prior knowledge that is either innate or learned via interactions with the environment. We will describe a general framework of "hierarchical Bayesian inference" that we and others have used to explore the role of cortico-cortical feedback in the visual system, and we will further argue that this approach to "seeing" makes our visual systems prone to perceptual errors in a variety of different ways. In this deliberately provocative and biased perspective, we argue that the neuromodulator, dopamine, may be a crucial link between neural circuits performing Bayesian inference and the perceptual idiosyncrasies of people with schizophrenia.
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Affiliation(s)
- Richard T Born
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Gianluca M Bencomo
- Department of Computer Science, Whittier College, Whittier, California, USA
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8
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Heightened perception of illusory motion is associated with symptom severity in schizophrenia patients. Prog Neuropsychopharmacol Biol Psychiatry 2021; 104:110055. [PMID: 32763343 DOI: 10.1016/j.pnpbp.2020.110055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 11/22/2022]
Abstract
Abnormal perceptual processing in schizophrenia may contribute to the development of positive symptoms such as hallucinations. Experimental findings suggest that such abnormalities result from impaired processing of local signals into complex cortical representations. Because complex processing is needed to generate the perception of illusory motion from local signals, deteriorated perception of illusory motion would be expected in schizophrenia. However, findings are mixed, and the relationship between complex motion processing and symptoms is unclear. Illusions with multiple flow components (e.g. rotation/expansion) are known to strongly engage specialized complex processing mechanisms that may be abnormal in schizophrenia, but have not yet been investigated. We used a recently constructed paradigm based on the Pinna-Brelstaff illusion to manipulate complex-flow illusory perception in a quantitative manner and probe associations with dimensional symptoms. In 102 patients and 90 controls, perceived speed and perceptual variability for the PBF were measured across a range of parameters. Meanwhile, eye movement was recorded and gaze parameters were analysed to examine effects on illusory perception. Our results showed that patients experienced faster illusory rotation than controls, while they made fewer eye fixations. This heightened illusory perception was significantly correlated with positive and general, but not negative, symptom scores. Our results indicate that unusual processing of complex-flow motion in patients may be specifically related to dimensional symptoms, which could provide a promising strategy for parsing heterogeneity in the schizophrenia syndrome. This further highlights the role of motion perception abnormalities in the pathophysiology of schizophrenia, thus encouraging future investigation into visual remediation therapeutics.
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9
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Affiliation(s)
- Jeff P. Hamm
- School of Psychology, The University of Auckland, Auckland, New Zealand
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10
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Kaliuzhna M, Stein T, Sterzer P, Seymour KJ. Examining motion speed processing in schizophrenia using the flash lag illusion. Schizophr Res Cogn 2020; 19:100165. [PMID: 31832345 PMCID: PMC6890935 DOI: 10.1016/j.scog.2019.100165] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/23/2019] [Accepted: 09/26/2019] [Indexed: 01/29/2023]
Abstract
Research on visual perception in schizophrenia suggests a deficit in motion processing. Specifically, difficulties with discriminating motion speed are commonly reported. However, speed discrimination tasks typically require participants to make judgments about the difference between two stimuli in a two-interval forced choice (2IFC) task. Such tasks not only tap into speed processing mechanisms, but also rely on higher executive functioning including working memory and attention which has been shown to be compromised in schizophrenia. We used the Flash Lag illusion to examine speed processing in patients with schizophrenia. Based on previous research showing a strong dependence between motion speed and the illusion magnitude, we expected a deficit in speed processing to alter this relationship. A motion processing deficit in patients would also predict overall reductions in perceived lag. We found the magnitude and speed dependence of the Flash Lag illusion to be similar in patients and controls. Together, the findings suggest no general abnormality in motion speed processing in schizophrenia.
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Affiliation(s)
- Mariia Kaliuzhna
- Clinical and Experimental Psychopathology Group, Department of Psychiatry, University of Geneva, Switzerland
| | - Timo Stein
- Department of Psychology, University of Amsterdam, Netherlands
| | - Philipp Sterzer
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité Universitätsmedizin Berlin, Germany
- Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Germany
| | - Kiley J. Seymour
- School of Psychology, The MARCS Institute for Brain, Behaviour and Development, Translational Health Research Institute, Western Sydney University, New South Wales, Australia
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11
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Kaliuzhna M, Stein T, Rusch T, Sekutowicz M, Sterzer P, Seymour KJ. No evidence for abnormal priors in early vision in schizophrenia. Schizophr Res 2019; 210:245-254. [PMID: 30587425 DOI: 10.1016/j.schres.2018.12.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 12/31/2022]
Abstract
The predictive coding account of psychosis postulates the abnormal formation of prior beliefs in schizophrenia, resulting in psychotic symptoms. One domain in which priors play a crucial role is visual perception. For instance, our perception of brightness, line length, and motion direction are not merely based on a veridical extraction of sensory input but are also determined by expectation (or prior) of the stimulus. Formation of such priors is thought to be governed by the statistical regularities within natural scenes. Recently, the use of such priors has been attributed to a specific set of well-documented visual illusions, supporting the idea that perception is biased toward what is statistically more probable within the environment. The Predictive Coding account of psychosis proposes that patients form abnormal representations of statistical regularities in natural scenes, leading to altered perceptual experiences. Here we use classical vision experiments involving a specific set of visual illusions to directly test this hypothesis. We find that perceptual judgments for both patients and control participants are biased in accordance with reported probability distributions of natural scenes. Thus, despite there being a suggested link between visual abnormalities and psychotic symptoms in schizophrenia, our results provide no support for the notion that altered formation of priors is a general feature of the disorder. These data call for a refinement in the predictions of quantitative models of psychosis.
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Affiliation(s)
- Mariia Kaliuzhna
- ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Macquarie University, Sydney, NSW, Australia; Clinical and Experimental Psychopathology Group, Department of Psychiatry, University of Geneva, Switzerland
| | - Timo Stein
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité Universitätsmedizin Berlin, Germany; Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Germany; Department of Psychology, University of Amsterdam, the Netherlands
| | - Tessa Rusch
- Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Maria Sekutowicz
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité Universitätsmedizin Berlin, Germany; Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Germany
| | - Philipp Sterzer
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité Universitätsmedizin Berlin, Germany; Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Germany
| | - Kiley J Seymour
- ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Macquarie University, Sydney, NSW, Australia; Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité Universitätsmedizin Berlin, Germany; School of Social Sciences and Psychology, Western Sydney University, New South Wales, Australia.
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12
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Valton V, Karvelis P, Richards KL, Seitz AR, Lawrie SM, Seriès P. Acquisition of visual priors and induced hallucinations in chronic schizophrenia. Brain 2019; 142:2523-2537. [PMID: 31257444 PMCID: PMC6734996 DOI: 10.1093/brain/awz171] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/01/2019] [Accepted: 04/21/2019] [Indexed: 01/10/2023] Open
Abstract
Prominent theories suggest that symptoms of schizophrenia stem from learning deficiencies resulting in distorted internal models of the world. To test these theories further, we used a visual statistical learning task known to induce rapid implicit learning of the stimulus statistics. In this task, participants are presented with a field of coherently moving dots and are asked to report the presented direction of the dots (estimation task), and whether they saw any dots or not (detection task). Two of the directions were more frequently presented than the others. In controls, the implicit acquisition of the stimuli statistics influences their perception in two ways: (i) motion directions are perceived as being more similar to the most frequently presented directions than they really are (estimation biases); and (ii) in the absence of stimuli, participants sometimes report perceiving the most frequently presented directions (a form of hallucinations). Such behaviour is consistent with probabilistic inference, i.e. combining learnt perceptual priors with sensory evidence. We investigated whether patients with chronic, stable, treated schizophrenia (n = 20) differ from controls (n = 23) in the acquisition of the perceptual priors and/or their influence on perception. We found that although patients were slower than controls, they showed comparable acquisition of perceptual priors, approximating the stimulus statistics. This suggests that patients have no statistical learning deficits in our task. This may reflect our patients' relative wellbeing on antipsychotic medication. Intriguingly, however, patients experienced significantly fewer (P = 0.016) hallucinations of the most frequently presented directions than controls when the stimulus was absent or when it was very weak (prior-based lapse estimations). This suggests that prior expectations had less influence on patients' perception than on controls when stimuli were absent or below perceptual threshold.
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Affiliation(s)
- Vincent Valton
- Institute for Adaptive and Neural Computation, University of Edinburgh, UK
- Department of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, UK
- Institute of Cognitive Neuroscience, University College London, London, UK
| | - Povilas Karvelis
- Institute for Adaptive and Neural Computation, University of Edinburgh, UK
| | - Katie L Richards
- Department of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, UK
| | - Aaron R Seitz
- Department of Psychology, University of California Riverside, CA, USA
| | - Stephen M Lawrie
- Department of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, UK
- Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | - Peggy Seriès
- Institute for Adaptive and Neural Computation, University of Edinburgh, UK
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Comparisons of flashILM, transformational apparent motion, and polarized gamma motion indicate these are three independent and separable illusions. Atten Percept Psychophys 2019; 81:517-532. [PMID: 30488188 DOI: 10.3758/s13414-018-1632-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Illusory line motion (ILM) refers to perceived motion in a bar when it is presented all at once. Explanations for ILM include low-level visual accounts, visual attention, and object tracking. These explanations tend to arise from studies using different protocols to induce ILM, based on the assumption that the same illusion is being generated. Using real motion in the same and in the opposite direction as the ILM quantifies the illusions from all protocols as the area between response curves for the left- and right-side inducers. This common measure enables testing of the assumption that two display configurations result in the same illusion. If there is a common underlying cause, an individual who shows a strong illusion in one situation should show a strong illusion in the other, but illusions that arise through different systems should not correlate. This approach has differentiated ILM induced by a flash (flashILM) from ILM induced by matching the bar to an attribute of the inducing stimuli (transformational apparent motion, TAM). The former is thought to reflect attention, while the latter is thought to reflect object processing. Low-level visual explanations are often offered based on ILM that occurs when the bar is adjacent to only a single inducer (polarized gamma motion, PGM) rather than between two stimuli (flashILM and TAM). The present study replicates the independence of flashILM and TAM and shows that neither is related to PGM, suggesting that all three explanations for ILM are warranted and that the debates in the literature are conflating at least three different illusions.
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McGuire K, Pinny A, Hamm JP. Cancelling Flash Illusory Line Motion by Cancelling the Attentional Gradient and a Consideration of Consciousness. Vision (Basel) 2019; 3:E3. [PMID: 31735804 PMCID: PMC6802763 DOI: 10.3390/vision3010003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/26/2018] [Accepted: 01/07/2019] [Indexed: 11/16/2022] Open
Abstract
Illusory line motion (ILM) refers to the perception of motion in a line that is, in fact, presented in full at one time. One form of this illusion (flashILM) occurs when the line is presented between two objects following a brief luminance change in one of them and flashILM is thought to result from exogenous attention being captured by the flash. Exogenous attention fades with increasing delays, which predicts that flashILM should show a similar temporal pattern. Exogenous attention appears to follow flashILM to become more or less equally distributed along the line.The current study examines flashILM in order to test these predictions derived from the attentional explanation for flashILM and the results were consistent with them. The discussion then concludes with an exploratory analysis approach concerning states of consciousness and decision making and suggests a possible role for attention.
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Affiliation(s)
| | | | - Jeff P. Hamm
- School of Psychology, The University of Auckland, Auckland 1023, New Zealand
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15
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Grzeczkowski L, Roinishvili M, Chkonia E, Brand A, Mast FW, Herzog MH, Shaqiri A. Is the perception of illusions abnormal in schizophrenia? Psychiatry Res 2018; 270:929-939. [PMID: 30551346 DOI: 10.1016/j.psychres.2018.10.063] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 10/23/2018] [Accepted: 10/23/2018] [Indexed: 12/22/2022]
Abstract
There seems to be no common factor for visual perception, i.e., performance in visual tasks correlates only weakly with each other. Similar results were found with visual illusions. One may expect common visual factors for individuals suffering from pathologies that alter brain functioning, such as schizophrenia. For example, patients who are more severely affected by the disease, e.g., stronger positive symptoms, may show increased illusion magnitudes. Here, in the first experiment, we used a battery of seven visual illusions and a mental imagery questionnaire. Illusion magnitudes for the seven illusions did not differ significantly between the patients and controls. In addition, correlations between the different illusions and mental imagery were low. In the second experiment, we tested 59 patients (mostly outpatients) with ten visual illusions. As for the first experiment, patients and controls showed similar susceptibility to all but one visual illusion. Moreover, there were no significant correlations between different illusions, symptoms, or medication type. Thus, it seems that perception of visual illusions is mostly intact in schizophrenia.
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Affiliation(s)
- Lukasz Grzeczkowski
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Allgemeine und Experimentelle Psychologie, Department Psychologie, Ludwig-Maximilians-Universität München (LMU), Leopoldstraße 13, München 80802 Germany.
| | - Maya Roinishvili
- Laboratory of Vision Physiology, Beritashvili Centre of Experimental Biomedicine, Tbilisi, Georgia; Institute of Cognitive Neurosciences, Free University of Tbilisi, Tbilisi, Georgia
| | - Eka Chkonia
- Department of Psychiatry, Tbilisi State Medical University, Tbilisi, Georgia
| | - Andreas Brand
- Institute of Psychology and Cognition Research, University of Bremen, Germany
| | - Fred W Mast
- Department of Psychology, University of Bern, Switzerland
| | - Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - Albulena Shaqiri
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
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Riemer M. Delusions of control in schizophrenia: Resistant to the mind's best trick? Schizophr Res 2018; 197:98-103. [PMID: 29208423 DOI: 10.1016/j.schres.2017.11.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 11/05/2017] [Accepted: 11/24/2017] [Indexed: 11/29/2022]
Abstract
The existence of a free will is fiercely debated in neuroscience and philosophy. The debate has great impact on society and our self-understanding as human beings. Behavioral and electrophysiological data have challenged the intuitive assumption that human behavior is the result of conscious intentions. This notion has important implications for delusions of control in schizophrenia, where patients experience bodily movements as not being controlled by themselves. Current theories explain control delusions as a deficit to perceive certain aspects of motor control, but many findings are inconsistent with this idea. Here, an alternative view is proposed: Control delusions might be triggered by an even more veridical perception of the temporal order of intentions and actions. This hypothesis is supported by evidence that (a) conscious intentions in healthy subjects are often based on retrospective inferences, (b) temporal recalibrations of conscious percepts occur in healthy subjects and are disturbed in schizophrenia and (c) basic perceptual functions of schizophrenic patients are less influenced by expectations and therefore they can sometimes be closer to physical reality than those of healthy subjects.
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Affiliation(s)
- Martin Riemer
- German Center for Neurodegenerative Diseases (DZNE), Aging & Cognition Research Group, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany.
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Abstract
Illusory line motion (ILM) refers to perception of motion in a bar that onsets or offsets all at once. When the bar onsets or offsets between two boxes after one of the boxes flashes, the bar appears to shoot out of the flashed box (flashILM). If the bar offsets during the flash, it appears to contract into the flashed box (reverse ILM; rILM). Onset bars do not show rILM. Moreover, rILM and flashILM are not correlated, indicating they are two different illusions. To date, rILM has only been studied using a 50-ms flash where the bar offsets 16.7 ms after flash onset. It is not clear if rILM is due to the 16.7-ms flash-bar-removal stimulus onset asynchrony (SOA) or due to the flash offsetting after the bar. The current studies explore these parameters to better understand the conditions that lead to rILM. The results suggest that flashILM is sensitive to the temporal interval between flash onset and bar offset, while rILM appears to arise when the flash offsets after the bar has been removed regardless of the temporal interval between flash onset and bar removal. These results are consistent with flashILM reflecting visual exogenous attention while rILM may reflect the low-level spreading of subthreshold activation radiating from the flashed box. The findings are incorporated into the recent work that suggests that the literature concerning ILM is possibly conflating a number of different illusions of line motion, including polarized gamma motion (PGM), transformational apparent motion (TAM), and exogenous attention induced motion (flashILM).
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Abstract
Illusory line motion (ILM) refers to the perception of motion in a bar that is presented all at once next to an inducing stimulus. The experimental methods for producing and quantifying ILM are varied, and the resulting explanations are likewise at odds. The current study examined the explanations for ILM away from the inducing stimulus (bright or dark flash) using bars that either suddenly appear (onset bars) or suddenly disappear (offset bars). Real motion is used to cancel ILM, providing three measures to quantify ILM: the consistency of responding to only ILM in the absence of real motion; the distance between the points of subjective equality between ILM and the real motion; and the area between the curves relating perception of motion to the real and illusory conditions. ILM quantities for onset and offset bars are strongly correlated when the bar change occurs after the flash. However, onset bars presented during the flash do not show any evidence of ILM, whereas offset bars removed during the flash result in reverse ILM (rILM). Moreover, rILM and ILM are not correlated, suggesting they reflect two separate illusions. These results are consistent over the various measures of ILM.
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Comprehensive review: Computational modelling of schizophrenia. Neurosci Biobehav Rev 2017; 83:631-646. [PMID: 28867653 DOI: 10.1016/j.neubiorev.2017.08.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 07/08/2017] [Accepted: 08/30/2017] [Indexed: 12/21/2022]
Abstract
Computational modelling has been used to address: (1) the variety of symptoms observed in schizophrenia using abstract models of behavior (e.g. Bayesian models - top-down descriptive models of psychopathology); (2) the causes of these symptoms using biologically realistic models involving abnormal neuromodulation and/or receptor imbalance (e.g. connectionist and neural networks - bottom-up realistic models of neural processes). These different levels of analysis have been used to answer different questions (i.e. understanding behavioral vs. neurobiological anomalies) about the nature of the disorder. As such, these computational studies have mostly supported diverging hypotheses of schizophrenia's pathophysiology, resulting in a literature that is not always expanding coherently. Some of these hypotheses are however ripe for revision using novel empirical evidence. Here we present a review that first synthesizes the literature of computational modelling for schizophrenia and psychotic symptoms into categories supporting the dopamine, glutamate, GABA, dysconnection and Bayesian inference hypotheses respectively. Secondly, we compare model predictions against the accumulated empirical evidence and finally we identify specific hypotheses that have been left relatively under-investigated.
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King DJ, Hodgekins J, Chouinard PA, Chouinard VA, Sperandio I. A review of abnormalities in the perception of visual illusions in schizophrenia. Psychon Bull Rev 2017; 24:734-751. [PMID: 27730532 PMCID: PMC5486866 DOI: 10.3758/s13423-016-1168-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Specific abnormalities of vision in schizophrenia have been observed to affect high-level and some low-level integration mechanisms, suggesting that people with schizophrenia may experience anomalies across different stages in the visual system affecting either early or late processing or both. Here, we review the research into visual illusion perception in schizophrenia and the issues which previous research has faced. One general finding that emerged from the literature is that those with schizophrenia are mostly immune to the effects of high-level illusory displays, but this effect is not consistent across all low-level illusions. The present review suggests that this resistance is due to the weakening of top-down perceptual mechanisms and may be relevant to the understanding of symptoms of visual distortion rather than hallucinations as previously thought.
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Affiliation(s)
- Daniel J King
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Joanne Hodgekins
- Department of Clinical Psychology, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Philippe A Chouinard
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Virginie-Anne Chouinard
- Psychotic Disorders Division, McLean Hospital, Belmont, MA, USA
- Harvard Medical School, Department of Psychiatry, Boston, MA, USA
| | - Irene Sperandio
- School of Psychology, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom.
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21
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Experimental evidence for circular inference in schizophrenia. Nat Commun 2017; 8:14218. [PMID: 28139642 PMCID: PMC5290312 DOI: 10.1038/ncomms14218] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 12/07/2016] [Indexed: 01/05/2023] Open
Abstract
Schizophrenia (SCZ) is a complex mental disorder that may result in some combination of hallucinations, delusions and disorganized thinking. Here SCZ patients and healthy controls (CTLs) report their level of confidence on a forced-choice task that manipulated the strength of sensory evidence and prior information. Neither group's responses can be explained by simple Bayesian inference. Rather, individual responses are best captured by a model with different degrees of circular inference. Circular inference refers to a corruption of sensory data by prior information and vice versa, leading us to ‘see what we expect' (through descending loops), to ‘expect what we see' (through ascending loops) or both. Ascending loops are stronger for SCZ than CTLs and correlate with the severity of positive symptoms. Descending loops correlate with the severity of negative symptoms. Both loops correlate with disorganized symptoms. The findings suggest that circular inference might mediate the clinical manifestations of SCZ. Schizophrenia is a mental disorder characterized by hallucinations and delusions. Here the authors report a novel probabilistic inference task in which compared to healthy subjects, schizophrenia patients show greater degree of circular inference that matches the severity of their clinical symptoms.
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A comparison of colour, shape, and flash induced illusory line motion. Atten Percept Psychophys 2017; 79:911-928. [DOI: 10.3758/s13414-016-1269-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Jardri R, Hugdahl K, Hughes M, Brunelin J, Waters F, Alderson-Day B, Smailes D, Sterzer P, Corlett PR, Leptourgos P, Debbané M, Cachia A, Denève S. Are Hallucinations Due to an Imbalance Between Excitatory and Inhibitory Influences on the Brain? Schizophr Bull 2016; 42:1124-34. [PMID: 27261492 PMCID: PMC4988749 DOI: 10.1093/schbul/sbw075] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This review from the International Consortium on Hallucinations Research intends to question the pertinence of the excitatory-to-inhibitory (E/I) imbalance hypothesis as a model for hallucinations. A large number of studies suggest that subtle impairments of the E/I balance are involved in neurological and psychiatric conditions, such as schizophrenia. Emerging evidence also points to a role of the E/I balance in maintaining stable perceptual representations, suggesting it may be a plausible model for hallucinations. In support, hallucinations have been linked to inhibitory deficits as shown with impairment of gamma-aminobutyric acid transmission, N-methyl-d-aspartate receptor plasticity, reductions in gamma-frequency oscillations, hyperactivity in sensory cortices, and cognitive inhibition deficits. However, the mechanisms by which E/I dysfunctions at the cellular level might relate to clinical symptoms and cognitive deficits remain unclear. Given recent data advances in the field of clinical neuroscience, it is now possible to conduct a synthesis of available data specifically related to hallucinations. These findings are integrated with the latest computational frameworks of hallucinations, and recommendations for future research are provided.
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Affiliation(s)
- Renaud Jardri
- Univ Lille, CNRS UMR 9193, SCALab (psyCHIC Team) & CHU Lille, Psychiatry Department (CURE), Lille, France;
| | - Kenneth Hugdahl
- Department of Biological and Medical Psychology, University of Bergen; Department of Radiology, Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Matthew Hughes
- Brain & Psychological Sciences Centre, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Jérôme Brunelin
- Centre Interdisciplinaire de Recherche en Réadaptation et en Intégration Sociale (CIRRIS), Université Laval, Québec City, Québec, Canada; Université Lyon 1, INSERM U1028 & CNRS 5292, Lyon Neuroscience Research Centre (ΨR2 Team), Centre Hospitalier Le Vinatier, Lyon, France
| | - Flavie Waters
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, and Clinical Research Centre, Graylands Health Campus, North Metropolitan Area Health Service Mental Health, Perth, Western Australia, Australia
| | | | - Dave Smailes
- School of Health and Social Sciences, Leeds Trinity University, Leeds, UK
| | - Philipp Sterzer
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universtätsmedizin Berlin, Berlin, Germany
| | - Philip R Corlett
- Department of Psychiatry, Yale University, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT
| | - Pantelis Leptourgos
- Group for Neural Theory, INSERM U960, Institute of Cognitive Studies, École Normale Supérieure, Paris, France
| | - Martin Debbané
- Developmental Clinical Psychology Research Unit, Faculty of Psychology and Educational Sciences, University of Geneva, Geneva, Switzerland; Research Department of Clinical, Educational and Health Psychology, University College London, London, UK
| | - Arnaud Cachia
- Laboratoire de Psychologie du Développement et de l'Éducation de l'Enfant, UMR 8240, CNRS & Université Paris-Descartes (Sorbonne-Paris-Cité), Paris, France
| | - Sophie Denève
- Group for Neural Theory, INSERM U960, Institute of Cognitive Studies, École Normale Supérieure, Paris, France
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Schmack K, Schnack A, Priller J, Sterzer P. Perceptual instability in schizophrenia: Probing predictive coding accounts of delusions with ambiguous stimuli. SCHIZOPHRENIA RESEARCH-COGNITION 2015; 2:72-77. [PMID: 29114455 PMCID: PMC5609639 DOI: 10.1016/j.scog.2015.03.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 11/29/2022]
Abstract
Background Delusions, a core symptom of schizophrenia, are thought to arise from an alteration in predictive coding mechanisms that underlie perceptual inference. Here, we aimed to empirically test the hypothesized link between delusions and perceptual inference. Method 28 patients with schizophrenia and 32 healthy controls matched for age and gender took part in a behavioral experiment that assessed the influence of stabilizing predictions on perception of an ambiguous visual stimulus. Results Participants with schizophrenia exhibited a weaker tendency towards percept stabilization during intermittent viewing of the ambiguous stimulus compared to healthy controls. The tendency towards percept stabilization in participants with schizophrenia correlated negatively with delusional ideation as measured with a validated questionnaire. Conclusion Our results indicate an association between a weakened effect of sensory predictions in perceptual inference and delusions in schizophrenia. We suggest that attenuated predictive signaling during perceptual inference in schizophrenia may yield the experience of aberrant salience, thereby providing the starting point for the formation of delusions.
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Affiliation(s)
- Katharina Schmack
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Alexandra Schnack
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Josef Priller
- Department of Neuropsychiatry, Charité Universitätsmedizin Berlin, NeuroCure, DZNE and BIH, Charitéplatz 1, 10117 Berlin, Germany
| | - Philipp Sterzer
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.,Bernstein Center for Computational Neuroscience, Charité Universitätsmedizin Berlin, Philippstrasse 13, Haus 6, 10117 Berlin, Germany.,Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
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25
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Notredame CE, Pins D, Deneve S, Jardri R. What visual illusions teach us about schizophrenia. Front Integr Neurosci 2014; 8:63. [PMID: 25161614 PMCID: PMC4130106 DOI: 10.3389/fnint.2014.00063] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/23/2014] [Indexed: 11/18/2022] Open
Abstract
Illusion, namely a mismatch between the objective and perceived properties of an object present in the environment, is a common feature of visual perception, both in normal and pathological conditions. This makes illusion a valuable tool with which to explore normal perception and its impairments. Although still debated, the hypothesis of a modified, and typically diminished, susceptibility to illusions in schizophrenia patients is supported by a growing number of studies. The current paper aimed to review how illusions have been used to explore and reveal the core features of visual perception in schizophrenia from a psychophysical, neurophysiological and functional point of view. We propose an integration of these findings into a common hierarchical Bayesian inference framework. The Bayesian formalism considers perception as the optimal combination between sensory evidence and prior knowledge, thereby highlighting the interweaving of perceptions and beliefs. Notably, it offers a holistic and convincing explanation for the perceptual changes observed in schizophrenia that might be ideally tested using illusory paradigms, as well as potential paths to explore neural mechanisms. Implications for psychopathology (in terms of positive symptoms, subjective experience or behavior disruptions) are critically discussed.
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Affiliation(s)
- Charles-Edouard Notredame
- Pediatric Psychiatry Department, University Medical Centre of Lille Lille, France ; SCA-Lab, PSYCHIC Team, Université Lille Nord de France Lille, France
| | - Delphine Pins
- SCA-Lab, PSYCHIC Team, Université Lille Nord de France Lille, France
| | - Sophie Deneve
- Group for Neural Theory, INSERM U960, Institute of Cognitive Studies, École Normale Supérieure Paris, France
| | - Renaud Jardri
- Pediatric Psychiatry Department, University Medical Centre of Lille Lille, France ; SCA-Lab, PSYCHIC Team, Université Lille Nord de France Lille, France ; Group for Neural Theory, INSERM U960, Institute of Cognitive Studies, École Normale Supérieure Paris, France
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26
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Hamm JP, Crawford TJ, Nebl H, Kean M, Williams SCR, Ettinger U. Neural correlates of illusory line motion. PLoS One 2014; 9:e87595. [PMID: 24475313 PMCID: PMC3903774 DOI: 10.1371/journal.pone.0087595] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 12/24/2013] [Indexed: 12/27/2022] Open
Abstract
Illusory line motion (ILM) refers to a motion illusion in which a flash at one end of a bar prior to the bar's instantaneous presentation or removal results in the percept of motion. While some theories attribute the origin of ILM to attention or early perceptual mechanisms, others have proposed that ILM results from impletion mechanisms that reinterpret the static bar as one in motion. The current functional magnetic resonance imaging study examined participants while they made decisions about the direction of motion in which a bar appeared to be removed. Preceding the instantaneous removal of the bar with a flash at one end resulted in a motion percept away from the flash. If this flash and the bar's removal overlapped in time, it appeared that the bar was removed towards the flash (reverse ILM). Independent of the motion type, brain responses indicated activations in areas associated with motion (MT+), endogenous and exogenous attention (intraparietal sulcus, frontal eye fields, and ventral frontal cortex), and response selection (ACC). ILM was associated with lower percept scores and higher activations in ACC relative to real motion, but no differences in shape-selective areas emerged. This pattern of brain activation is consistent with the attentional gradient model or bottom-up accounts of ILM in preference to impletion.
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Affiliation(s)
- Jeff P. Hamm
- Cognitive Neuroscience Research Group, School of Psychology, The University of Auckland, Auckland, New Zealand
- * E-mail: (JPM); (TJC); (HN); (UE)
| | - Trevor J. Crawford
- Centres for Aging Research & Human Learning and Development, Department of Psychology, Lancaster University, Lancaster, United Kingdom
- * E-mail: (JPM); (TJC); (HN); (UE)
| | - Helmut Nebl
- Study Programme Psychology, University of Regensburg, Regensburg, Germany
- * E-mail: (JPM); (TJC); (HN); (UE)
| | - Matthew Kean
- Manchester Medical School, Manchester, United Kingdom
| | - Steven C. R. Williams
- Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Ulrich Ettinger
- Department of Psychology, University of Bonn, Bonn, Germany
- * E-mail: (JPM); (TJC); (HN); (UE)
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Abstract
A considerable number of recent experimental and computational studies suggest that subtle impairments of excitatory to inhibitory balance or regulation are involved in many neurological and psychiatric conditions. The current paper aims to relate, specifically and quantitatively, excitatory to inhibitory imbalance with psychotic symptoms in schizophrenia. Considering that the brain constructs hierarchical causal models of the external world, we show that the failure to maintain the excitatory to inhibitory balance results in hallucinations as well as in the formation and subsequent consolidation of delusional beliefs. Indeed, the consequence of excitatory to inhibitory imbalance in a hierarchical neural network is equated to a pathological form of causal inference called 'circular belief propagation'. In circular belief propagation, bottom-up sensory information and top-down predictions are reverberated, i.e. prior beliefs are misinterpreted as sensory observations and vice versa. As a result, these predictions are counted multiple times. Circular inference explains the emergence of erroneous percepts, the patient's overconfidence when facing probabilistic choices, the learning of 'unshakable' causal relationships between unrelated events and a paradoxical immunity to perceptual illusions, which are all known to be associated with schizophrenia.
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Affiliation(s)
- Renaud Jardri
- 1 Group for Neural Theory, INSERM U960, Institute of Cognitive Studies, École Normale Supérieure, 75005 Paris, France
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28
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Sanders LLO, de Millas W, Heinz A, Kathmann N, Sterzer P. Apparent motion perception in patients with paranoid schizophrenia. Eur Arch Psychiatry Clin Neurosci 2013; 263:233-9. [PMID: 22865160 DOI: 10.1007/s00406-012-0344-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/17/2012] [Indexed: 12/11/2022]
Abstract
Impaired perceptual inference has been suggested to be at the core of positive symptoms in schizophrenia. Apparent motion (AM) is a visual illusion in which perceptual inference gives rise to the experience of a single object moving back and forth when two spatially separated objects are flashed in alternation. Here, we investigated the strength of AM perception in patients with paranoid schizophrenia. Patients were less susceptible to the illusion as indicated by a lower probability of motion perception at the individual's optimal presentation frequency for AM. In addition, the probability of AM perception was inversely related to delusional conviction in the patient group. These results suggest that schizophrenia may be associated with a reduced susceptibility to visual phenomena that commonly rely on perceptual inference.
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Affiliation(s)
- Lia Lira Olivier Sanders
- Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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29
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Abstract
The line-motion illusion has been regarded as the result of attention. An alternative interpretation is that the illusion is related to apparent motion which would predict the stimuli to contain motion energy associated with the direction of the illusory motion. In order to examine this possibility Fourier transforms of x-t plots of line-motion stimuli were generated under a variety of conditions. The sums of amplitudes associated with movement in the directions away from the cue relative to that towards the cue were compared to previously published psychophysical observations. It was found that the amplitude sums are largely consistent with the psychophysical results. In the few cases where there were discrepancies between results based on amplitude spectra and psychophysical findings, these discrepancies could be accounted for by making relatively simple and plausible assumptions. The present observations suggest that motion energy may be sufficient to account for the line-motion illusion.
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30
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Abstract
Motion processing represents a perceptual domain in which dynamic visual information is encoded to support the perception of movement. Research over the last decade has found a variety of abnormalities in the processing of motion information in schizophrenia. The abnormalities span from discrimination of basic motion features (such as speed) to integration of spatially distributed motion signals (such as coherent motion). Motion processing involves visual signals across space and time and thus presents a special opportunity to examine how spatial and temporal information is integrated in the visual system. This article surveys the behavioral and neuroimaging studies that probe into the spatial integration of motion information in schizophrenia. An emerging theme from these studies points to an imbalanced regulation of spatial interaction processes as a potential mechanism mediating different levels of abnormal motion processing in schizophrenia. The synthesis of these mechanism-driven studies suggests that further investigation of the neural basis and functional consequences of this abnormal motion processing are needed in order to render a basic biomarker for assessment and intervention of cognitive dysfunction in this mental disorder.
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Affiliation(s)
- Y. Chen
- To whom correspondence should be addressed. tel: 617-855-3615, fax: 617-855-3611, e-mail:
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