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Amerio P, Michel M, Goerttler S, Peters MAK, Cleeremans A. Unconscious Perception of Vernier Offsets. Open Mind (Camb) 2024; 8:739-765. [PMID: 38895041 PMCID: PMC11185422 DOI: 10.1162/opmi_a_00145] [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: 12/15/2023] [Accepted: 04/15/2024] [Indexed: 06/21/2024] Open
Abstract
The comparison between conscious and unconscious perception is a cornerstone of consciousness science. However, most studies reporting above-chance discrimination of unseen stimuli do not control for criterion biases when assessing awareness. We tested whether observers can discriminate subjectively invisible offsets of Vernier stimuli when visibility is probed using a bias-free task. To reduce visibility, stimuli were either backward masked or presented for very brief durations (1-3 milliseconds) using a modern-day Tachistoscope. We found some behavioral indicators of perception without awareness, and yet, no conclusive evidence thereof. To seek more decisive proof, we simulated a series of Bayesian observer models, including some that produce visibility judgements alongside type-1 judgements. Our data are best accounted for by observers with slightly suboptimal conscious access to sensory evidence. Overall, the stimuli and visibility manipulations employed here induced mild instances of blindsight-like behavior, making them attractive candidates for future investigation of this phenomenon.
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Affiliation(s)
- Pietro Amerio
- Consciousness, Cognition & Computation Group, Center for Research in Cognition & Neurosciences, ULB Neuroscience Institute, Université libre de Bruxelles
| | - Matthias Michel
- Consciousness, Cognition & Computation Group, Center for Research in Cognition & Neurosciences, ULB Neuroscience Institute, Université libre de Bruxelles
- Center for Mind, Brain and Consciousness, New York University
| | - Stephan Goerttler
- Consciousness, Cognition & Computation Group, Center for Research in Cognition & Neurosciences, ULB Neuroscience Institute, Université libre de Bruxelles
| | | | - Axel Cleeremans
- Consciousness, Cognition & Computation Group, Center for Research in Cognition & Neurosciences, ULB Neuroscience Institute, Université libre de Bruxelles
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Sánchez-Fuenzalida N, van Gaal S, Fleming SM, Haaf JM, Fahrenfort JJ. Predictions and rewards affect decision-making but not subjective experience. Proc Natl Acad Sci U S A 2023; 120:e2220749120. [PMID: 37878723 PMCID: PMC10622870 DOI: 10.1073/pnas.2220749120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 09/12/2023] [Indexed: 10/27/2023] Open
Abstract
To survive, organisms constantly make decisions to avoid danger and maximize rewards in information-rich environments. As a result, decisions about sensory input are not only driven by sensory information but also by other factors, such as the expected rewards of a decision (known as the payoff matrix) or by information about temporal regularities in the environment (known as cognitive priors or predictions). However, it is unknown to what extent these different types of information affect subjective experience or whether they merely result in nonperceptual response criterion shifts. To investigate this question, we used three carefully matched manipulations that typically result in behavioral shifts in decision criteria: a visual illusion (Müller-Lyer condition), a punishment scheme (payoff condition), and a change in the ratio of relevant stimuli (base rate condition). To gauge shifts in subjective experience, we introduce a task in which participants not only make decisions about what they have just seen but are also asked to reproduce their experience of a target stimulus. Using Bayesian ordinal modeling, we show that each of these three manipulations affects the decision criterion as intended but that the visual illusion uniquely affects sensory experience as measured by reproduction. In a series of follow-up experiments, we use computational modeling to show that although the visual illusion results in a distinct drift-diffusion (DDM) parameter profile relative to nonsensory manipulations, reliance on DDM parameter estimates alone is not sufficient to ascertain whether a given manipulation is perceptual or nonperceptual.
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Affiliation(s)
- Nicolás Sánchez-Fuenzalida
- Department of Psychology, University of Amsterdam, Amsterdam1001NK, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, Amsterdam1001NK, The Netherlands
| | - Simon van Gaal
- Department of Psychology, University of Amsterdam, Amsterdam1001NK, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, Amsterdam1001NK, The Netherlands
| | - Stephen M. Fleming
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, LondonWC1N 3AR, United Kingdom
- Department of Experimental Psychology, University College London, LondonWC1H 0AP, United Kingdom
- Max Planck Centre for Computational Psychiatry and Ageing Research, University College London, LondonWC1B 5EH, United Kingdom
| | - Julia M. Haaf
- Department of Psychology, University of Amsterdam, Amsterdam1001NK, The Netherlands
| | - Johannes J. Fahrenfort
- Department of Psychology, University of Amsterdam, Amsterdam1001NK, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, Amsterdam1001NK, The Netherlands
- Department of Applied and Experimental Psychology, Vrije Universiteit Amsterdam, Amsterdam1081HV, The Netherlands
- Institute for Brain and Behavior Amsterdam, Vrije Universiteit Amsterdam, Amsterdam1081HV, The Netherlands
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Aydin M, Carpenelli AL, Lucia S, Di Russo F. The Dominance of Anticipatory Prefrontal Activity in Uncued Sensory-Motor Tasks. SENSORS (BASEL, SWITZERLAND) 2022; 22:6559. [PMID: 36081018 PMCID: PMC9460036 DOI: 10.3390/s22176559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/25/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Anticipatory event-related potentials (ERPs) precede upcoming events such as stimuli or actions. These ERPs are usually obtained in cued sensory-motor tasks employing a warning stimulus that precedes a probe stimulus as in the contingent negative variation (CNV) paradigms. The CNV wave has been widely studied, from clinical to brain-computer interface (BCI) applications, and has been shown to emerge in medial frontoparietal areas, localized in the cingulate and supplementary motor areas. Several dated studies also suggest the existence of a prefrontal CNV, although this component was not confirmed by later studies due to the contamination of ocular artifacts. Another lesser-known anticipatory ERP is the prefrontal negativity (pN) that precedes the uncued probe stimuli in discriminative response tasks and has been localized in the inferior frontal gyrus. This study aimed to characterize the pN by comparing it with the CNV in cued and uncued tasks and test if the pN could be associated with event preparation, temporal preparation, or both. To achieve these aims, high-density electroencephalographic recording and advanced ERP analysis controlling for ocular activity were obtained in 25 volunteers who performed 4 different visuomotor tasks. Our results showed that the pN amplitude was largest in the condition requiring both time and event preparation, medium in the condition requiring event preparation only, and smallest in the condition requiring temporal preparation only. We concluded that the prefrontal CNV could be associated with the pN, and this activity emerges in complex tasks requiring the anticipation of both the category and timing of the upcoming stimulus. The proposed method can be useful in BCI studies investigating the endogenous neural signatures triggered by different sensorimotor paradigms.
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Affiliation(s)
- Merve Aydin
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy
| | | | - Stefania Lucia
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy
| | - Francesco Di Russo
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy
- Santa Lucia Foundation IRCCS, 00179 Rome, Italy
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Francken JC, Beerendonk L, Molenaar D, Fahrenfort JJ, Kiverstein JD, Seth AK, van Gaal S. An academic survey on theoretical foundations, common assumptions and the current state of consciousness science. Neurosci Conscious 2022; 2022:niac011. [PMID: 35975240 PMCID: PMC9374479 DOI: 10.1093/nc/niac011] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 05/13/2022] [Accepted: 07/27/2022] [Indexed: 11/24/2022] Open
Abstract
We report the results of an academic survey into the theoretical and methodological foundations, common assumptions, and the current state of the field of consciousness research. The survey consisted of 22 questions and was distributed on two different occasions of the annual meeting of the Association of the Scientific Study of Consciousness (2018 and 2019). We examined responses from 166 consciousness researchers with different backgrounds (e.g. philosophy, neuroscience, psychology, and computer science) and at various stages of their careers (e.g. junior/senior faculty and graduate/undergraduate students). The results reveal that there remains considerable discussion and debate between the surveyed researchers about the definition of consciousness and the way it should be studied. To highlight a few observations, a majority of respondents believe that machines could have consciousness, that consciousness is a gradual phenomenon in the animal kingdom, and that unconscious processing is extensive, encompassing both low-level and high-level cognitive functions. Further, we show which theories of consciousness are currently considered most promising by respondents and how supposedly different theories cluster together, which dependent measures are considered best to index the presence or absence of consciousness, and which neural measures are thought to be the most likely signatures of consciousness. These findings provide us with a snapshot of the current views of researchers in the field and may therefore help prioritize research and theoretical approaches to foster progress.
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Affiliation(s)
- Jolien C Francken
- Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Institute for Interdisciplinary Studies, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands
- Faculty of Philosophy, Theology and Religious Sciences, Radboud University, Erasmusplein 1, 6525 HT, Nijmegen, the Netherlands
| | - Lola Beerendonk
- Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
| | - Dylan Molenaar
- Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
| | - Johannes J Fahrenfort
- Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Department of Experimental and Applied Psychology, Vrije Universiteit, Van der Boechorststraat 7, 1081 BT, Amsterdam, the Netherlands
| | - Julian D Kiverstein
- Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Anil K Seth
- Department of Informatics, University of Sussex, Sussex House, Falmer, Brighton BN1 9RH, UK
- Sackler Centre for Consciousness Science, University of Sussex, Sussex House, Falmer, Brighton BN1 9RH, UK
- Canadian Institute for Advanced Research (CIFAR) Program on Brain, Mind, and Consciousness, MaRS Centre, West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Simon van Gaal
- Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WS, Amsterdam, the Netherlands
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Dijkstra N, van Gaal S, Geerligs L, Bosch SE, van Gerven MAJ. No Evidence for Neural Overlap between Unconsciously Processed and Imagined Stimuli. eNeuro 2021; 8:ENEURO.0228-21.2021. [PMID: 34593516 PMCID: PMC8577044 DOI: 10.1523/eneuro.0228-21.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/23/2022] Open
Abstract
Visual representations can be generated via feedforward or feedback processes. The extent to which these processes result in overlapping representations remains unclear. Previous work has shown that imagined stimuli elicit similar representations as perceived stimuli throughout the visual cortex. However, while representations during imagery are indeed only caused by feedback processing, neural processing during perception is an interplay of both feedforward and feedback processing. This means that any representational overlap could be because of overlap in feedback processes. In the current study, we aimed to investigate this issue by characterizing the overlap between feedforward- and feedback-initiated category representations during imagined stimuli, conscious perception, and unconscious processing using fMRI in humans of either sex. While all three conditions elicited stimulus representations in left lateral occipital cortex (LOC), significant similarities were observed only between imagery and conscious perception in this area. Furthermore, connectivity analyses revealed stronger connectivity between frontal areas and left LOC during conscious perception and in imagery compared with unconscious processing. Together, these findings can be explained by the idea that long-range feedback modifies visual representations, thereby reducing representational overlap between purely feedforward- and feedback-initiated stimulus representations measured by fMRI. Neural representations influenced by feedback, either stimulus driven (perception) or purely internally driven (imagery), are, however, relatively similar.
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Affiliation(s)
- Nadine Dijkstra
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 GL, Nijmegen, The Netherlands
- Wellcome Centre for Human Neuroimaging, University College London, London WC1N 3AR, United Kingdom
| | - Simon van Gaal
- Department of Psychology, Brain & Cognition, University of Amsterdam, 1000 GG, Amsterdam, The Netherlands
| | - Linda Geerligs
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 GL, Nijmegen, The Netherlands
| | - Sander E Bosch
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 GL, Nijmegen, The Netherlands
| | - Marcel A J van Gerven
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 GL, Nijmegen, The Netherlands
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Representational dynamics preceding conscious access. Neuroimage 2021; 230:117789. [PMID: 33497774 DOI: 10.1016/j.neuroimage.2021.117789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/08/2020] [Accepted: 01/12/2021] [Indexed: 11/20/2022] Open
Abstract
Our senses are continuously bombarded with more information than our brain can process up to the level of awareness. The present study aimed to enhance understanding on how attentional selection shapes conscious access under conditions of rapidly changing input. Using an attention task, EEG, and multivariate decoding of individual target- and distractor-defining features, we specifically examined dynamic changes in the representation of targets and distractors as a function of conscious access and the task-relevance (target or distractor) of the preceding item in the RSVP stream. At the behavioral level, replicating previous work and suggestive of a flexible gating mechanism, we found a significant impairment in conscious access to targets (T2) that were preceded by a target (T1) followed by one or two distractors (i.e., the attentional blink), but striking facilitation of conscious access to targets shown directly after another target (i.e., lag-1 sparing and blink reversal). At the neural level, conscious access to T2 was associated with enhanced early- and late-stage T1 representations and enhanced late-stage D1 representations, and interestingly, could be predicted based on the pattern of EEG activation well before T1 was presented. Yet, across task conditions, we did not find convincing evidence for the notion that conscious access is affected by rapid top-down selection-related modulations of the strength of early sensory representations induced by the preceding visual event. These results cannot easily be explained by existing accounts of how attentional selection shapes conscious access under rapidly changing input conditions, and have important implications for theories of the attentional blink and consciousness more generally.
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Subjective visibility report is facilitated by conscious predictions only. Conscious Cogn 2020; 87:103048. [PMID: 33262026 DOI: 10.1016/j.concog.2020.103048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/05/2020] [Accepted: 11/04/2020] [Indexed: 11/21/2022]
Abstract
Predictions in the visual domain have been shown to modulate conscious access. Yet, little is known about how predictions may do so and to what extent they need to be consciously implemented to be effective. To address this, we administered an attentional blink (AB) task in which target 1 (T1) identity predicted target 2 (T2) identity, while participants rated their perceptual awareness of validly versus invalidly predicted T2s (Experiment 1 & 2) or reported T2 identity (Experiment 3). Critically, we tested the effects of conscious and non-conscious predictions, after seen and unseen T1s, on T2 visibility. We found that valid predictions increased subjective visibility reports and discrimination of T2s, but only when predictions were generated by a consciously accessed T1, irrespective of the timing at which the effects were measured (short vs. longs lags). These results further our understanding of the intricate relationship between predictive processing and consciousness.
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Bachmann T. The Set of Priors Related Concepts Instrumental in Understanding Conscious Perception Begs Clarification. Front Psychol 2020; 11:1293. [PMID: 32655453 PMCID: PMC7324745 DOI: 10.3389/fpsyg.2020.01293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 05/18/2020] [Indexed: 11/13/2022] Open
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