Intact and deficient contextual processing in schizophrenia patients

Choung, Oh-Hyeon; Gordillo, Darío; Roinishvili, Maya; Brand, Andreas; Herzog, Michael H.; Chkonia, Eka

doi:10.1016/j.scog.2022.100265

Cited by 2 publications

(4 citation statements)

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“…Our results may reconcile previously contradictory findings. Some authors proposed that positive symptoms in schizophrenia relate to abnormalities in prior expectations (Wacongne, 2016; Weilnhammer et al, 2020); on the other hand, other authors argued against this interpretation, based on indirect experimental findings, such as intact illusion perception and intact contextual processing (Choung et al, 2022; Grzeczkowski et al, 2018; Lhotka et al, 2023). To reconcile these contradicting findings, a more nuanced framework was proposed to account, separating priors in the lower areas from those in higher ones (Corlett et al, 2019; Sterzer et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

“…Within this Bayesian framework, it was proposed that schizophrenia patients weigh the prior information more strongly than the sensory information, explaining symptoms such as hallucinations or delusions (Friston et al, 2016; Krystal et al, 2017). Experimental evidence for the hypothesis from behavioral studies is mixed, with supportive ones (Cassidy et al, 2018; Powers et al, 2017), others which found stronger reliance on sensory information in the patients (Stuke et al, 2019; Weilnhammer et al, 2020), and even studies which found intact processing (Choung et al, 2022; Kaliuzhna et al, 2019; Tibber et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…According to this framework, perception combines incoming sensory evidence with prior information, i.e., beliefs about the world (figure 1A). However, experimental evidence from behavioral studies is mixed, including studies showing that patients rely more on prior beliefs than on sensory information (Cassidy et al, 2018; Powers et al, 2017), studies which found stronger reliance on sensory information in the patients (Stuke et al, 2019; Weilnhammer et al, 2020), and even studies which found intact processing (Choung et al, 2022; Kaliuzhna et al, 2019; Tibber et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Oscillatory traveling waves reveal predictive coding abnormalities in schizophrenia

Alamia,

Gordillo,

Chkonia

et al. 2023

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In recent years, increasing interest has been in describing the computational mechanisms underlying psychiatric disorders. Diverse hypotheses aim at characterizing cognitive and perceptual alterations in schizophrenia and its major symptoms. One hypothesis, grounded in the Bayesian predictive coding framework, proposes that schizophrenia patients have alterations in encoding prior beliefs about the environment, resulting in abnormal sensory inference that may underlie some core aspects of this psychopathology. Here, we test this hypothesis from a neurophysiological perspective, leveraging recent work identifying oscillatory traveling waves as neural signatures of predictive coding. By analyzing one of the largest EEG datasets, comprising 146 schizophrenia patients and 96 age-matched healthy controls, we found that schizophrenia patients have stronger top-down alpha-band traveling waves compared to healthy controls during resting state, thereby reflecting an increased flow of prior information from higher-level into sensory brain areas. EEG traveling waves during resting state were strongly correlated to those observed during a visual backward masking task, showing that schizophrenia patients have an inherent impairment in the flow of prior signals into sensory areas that spans many functioning domains. Importantly, the present results yield a novel spatial-based characterization of oscillatory dynamics in schizophrenia, considering brain rhythms as traveling waves and providing a unique framework to study the different components involved in a predictive coding scheme. Altogether, our findings significantly advance our understanding of the mechanisms involved in fundamental pathophysiological aspects of schizophrenia, promoting a more comprehensive and hypothesis-driven approach to psychiatric disorders.SignificanceWe provide novel evidence favoring the Bayesian predictive coding interpretation of schizophrenia. Taking advantage of computational and experimental works that characterized the electrophysiological correlates of predictive processes, we investigate the pattern of oscillatory traveling waves in a large EEG dataset of 146 schizophrenia patients and 96 age-matched healthy controls. Our results reveal stronger top-down alpha-band traveling waves in schizophrenia patients, reflecting an alteration in the precision of their high-level priors.Traveling waves observed during resting-state were strongly correlated to those observed during a visual backward masking task, suggesting that traveling waves probe a general mechanism of predictive processing. Impairments in this mechanism may underlie some of the major perceptual and cognitive alterations as well as the pronounced clinical symptoms of schizophrenia. The strong hypothesis-driven nature of our results accentuates the relevance of our findings.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Oscillatory traveling waves reveal predictive coding abnormalities in schizophrenia

Alamia,

Gordillo,

Chkonia

et al. 2023

Preprint

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“…In this regard, even subtle stimuli differences can generate performance variability. For example, Choung et al ( 22 ) have shown that the same groups of normal observers and patients with schizophrenia have variable performance in flanker crowding of vernier stimulus depending on the flankers configuration and stimuli duration.…”

Section: Introductionmentioning

confidence: 99%

A neural model of modified excitation/inhibition and feedback levels in schizophrenia

2023

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IntroductionThe 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.MethodsTo 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.ResultsOur 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.DiscussionWe 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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Intact and deficient contextual processing in schizophrenia patients

Cited by 2 publications

References 64 publications

Oscillatory traveling waves reveal predictive coding abnormalities in schizophrenia

Oscillatory traveling waves reveal predictive coding abnormalities in schizophrenia

A neural model of modified excitation/inhibition and feedback levels in schizophrenia

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