Experimental and Theoretical Approaches to Conscious Processing

Experimental and Theoretical Approaches to Conscious Processing Dehaene Changeux

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Experimental and Theoretical Approaches to Conscious Processing 2011 Neuron 10.1016/j.neuron.2011.03.018 dehaene2011-experimental-and-theoretical-appro dehaene2011-experimental-and-theoretical-appro.txt, the project's staged copy 2cd2282294c92a2ad79e1be6ff5064af3d910263 open-access neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them mechanism Quotation withheld because this record is not cleared for redistribution. conscious access Quotation withheld because this record is not cleared for redistribution. review review Quotation withheld because this record is not cleared for redistribution. mechanisms incoming activity that exceeds a dynamical threshold ignites a self-supporting reverberating cell assembly which sustains the conscious content and broadcasts it to distant sites Quotation withheld because this record is not cleared for redistribution. mechanisms global broadcasting frees information from encapsulated circuits and makes it available to many processors, including the ones that formulate verbal reports, which is why conscious information is reportable Quotation withheld because this record is not cleared for redistribution. mechanisms during ignition the workspace is mobilised as a whole, with the non-selected neurons actively inhibited, which blocks a second simultaneous ignition and produces the serial bottleneck Quotation withheld because this record is not cleared for redistribution. mechanisms spontaneous prestimulus fluctuations barely affect the fast feedforward stage but strongly bias the slow NMDA-based reverberating stage, so an identical stimulus ignites on some trials and not others, producing all-or-none perception Quotation withheld because this record is not cleared for redistribution. mechanisms a weak stimulus produces a feedforward wave that cannot recruit enough self-sustaining reverberation, so it dies out before the late global activation and stays subliminal Quotation withheld because this record is not cleared for redistribution. mechanisms because far more workspace neurons are laterally inhibited than activated, the summed scalp signal during ignition is net positive, which is why conscious access shows up as the positive P3b status: the paper's own words: can explain why Quotation withheld because this record is not cleared for redistribution. The review deliberately covers only conscious access, not higher-order concepts of consciousness Quotation withheld because this record is not cleared for redistribution. Higher-order concepts such as metacognition and self-representation are excluded because the authors judge them insufficiently defined empirically Quotation withheld because this record is not cleared for redistribution. The supporting simulations implement only a small fragment of the proposed architecture Quotation withheld because this record is not cleared for redistribution. Lesion and TMS evidence does not establish that prefrontal contribution is causally necessary for conscious perception Quotation withheld because this record is not cleared for redistribution. The field's strict operational criterion is stated to OVERESTIMATE the thing it measures: subjects perform above chance while denying they perceived anything. what this limits: a chance-level performance criterion as the test of non-conscious processing: the review states it tends to overestimate conscious perception, because subjects can perform above chance and still deny perceiving the stimulus Quotation withheld because this record is not cleared for redistribution. Which task counts as evidence is unresolved, because performance can be at chance on one task and not another. what this limits: a null result on one task as evidence of non-conscious processing: the review states performance can be at chance for some tasks but not others, leaving which tasks count unresolved Quotation withheld because this record is not cleared for redistribution. The verdict rests on accepting a null hypothesis, and the review states the significance often depends on an analyst's choice of how many trials to run. what this limits: any published claim that a stimulus was processed non-consciously: the review states performance never really falls to zero and that significance often depends on arbitrary choices such as the number of trials used to measure it Quotation withheld because this record is not cleared for redistribution. the concept of a stochastic phase transition, used to describe the sudden switch of the network into the ignited conscious state Quotation withheld because this record is not cleared for redistribution. the blackboard architecture - a shared data structure updated by many specialised modules - taken over as the global workspace of consciousness Quotation withheld because this record is not cleared for redistribution. conscious access conscious access Quotation withheld because this record is not cleared for redistribution. attention attention Quotation withheld because this record is not cleared for redistribution. post-decision wagering post-decision wagering Quotation withheld because this record is not cleared for redistribution. state of consciousness state of consciousness Quotation withheld because this record is not cleared for redistribution. wakefulness wakefulness Quotation withheld because this record is not cleared for redistribution. vigilance vigilance Quotation withheld because this record is not cleared for redistribution. selective attention selective attention Quotation withheld because this record is not cleared for redistribution. conscious content conscious content Quotation withheld because this record is not cleared for redistribution. conscious access - BY THE OBJECTIVE CRITERION: a stimulus counts as non-conscious only if subjects cannot perform above chance on a direct task, a tradition grounded in signal-detection theory Quotation withheld because this record is not cleared for redistribution. conscious access - BY SUBJECTIVE CRITERIA: visibility ratings, or second-order commentaries such as post-decision wagering, adopted BECAUSE the objective criterion fails Quotation withheld because this record is not cleared for redistribution. attention - James's classic definition, which the review says CONFLATES two processes that are now clearly separable Quotation withheld because this record is not cleared for redistribution. `conscious` - ONE WORD SPLIT BY GRAMMAR, NOT BY FIELD OR BY DATE. `“Conscious” is an ambiguous word. In its intransitive use (e.g. "the patient was still conscious"), it refers to the state of consciousness ... In its transitive use (e.g. "I was not conscious of the red light"), it refers to conscious access.` The disambiguating test is whether the word takes an object. Every other split in this corpus runs across disciplines, across decades, or across languages; this one runs across a syntactic frame, and the paper hands the reader a grammatical test rather than a definition. Quotation withheld because this record is not cleared for redistribution. `selection` / `selective attention` - AN ALIAS INTRODUCED IN PASSING AND THEN USED TO BREAK A FOLK IDENTITY. `Selection, also called selective attention, refers to the separation of relevant versus irrelevant information`, and the paper immediately reports that `selection can occur without conscious processing`. The naming matters because the everyday word `attention` carries the implication that attending is being aware, and the paper is dismantling exactly that. Quotation withheld because this record is not cleared for redistribution. builds-on → Crick and Koch (1990) programme on the neural correlates of consciousness Quotation withheld because this record is not cleared for redistribution. builds-on → Dehaene et al. (1998a) global neuronal workspace architecture Quotation withheld because this record is not cleared for redistribution. conscious access —distinct-from→ attention conscious access attention strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. state of consciousness —same-as→ wakefulness state of consciousness wakefulness strength of the relation: 1 · note: 'also called' - an explicit alias, both names in the one span. Quotation withheld because this record is not cleared for redistribution. state of consciousness —same-as→ vigilance state of consciousness vigilance strength of the relation: 1 · note: Same 'also called' list. Confidence 0.85 rather than 0.9 because the paper then uses 'vigilance' as a POINT ON the scale ('full vigilance') as well as a name FOR the scale. Quotation withheld because this record is not cleared for redistribution. selective attention —distinct-from→ conscious access selective attention conscious access strength of the relation: 1 · note: A DISSOCIATION, and the strongest form of distinctness the paper offers: 'selection can occur without conscious processing'. This is an empirical claim, not a definitional stipulation, which is why it is evidenced by the dissociation sentence and not by the definition. Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span writes 'selection can occur without conscious processing', not 'selective attention' vs 'conscious access'. Quotation withheld because this record is not cleared for redistribution. Granger causality Granger causality Quotation withheld because this record is not cleared for redistribution. correlation (coefficient of determination) correlation (coefficient of determination) Quotation withheld because this record is not cleared for redistribution. sensitivity and specificity sensitivity and specificity Quotation withheld because this record is not cleared for redistribution. independent component analysis independent component analysis Quotation withheld because this record is not cleared for redistribution. Across many paradigms, conscious access is marked by three convergent physiological signatures: late amplification of the relevant sensory activity, long-distance cortico-cortical synchronisation in the beta and gamma bands, and ignition of a large-scale prefronto-parietal network. Quotation withheld because this record is not cleared for redistribution. Subliminal influence shrinks as processing depth increases, leaving only small effects at high-level cognitive and decision stages. Quotation withheld because this record is not cleared for redistribution. Subliminal priming decays with time and is typically undetectable beyond about 500 ms. Quotation withheld because this record is not cleared for redistribution. Subliminal stimuli do not produce durable or flexible changes in executive control. Quotation withheld because this record is not cleared for redistribution. The first 200 ms of visual processing can be fully preserved on trials where subjects deny seeing the stimulus. Quotation withheld because this record is not cleared for redistribution. The most consistent ERP correlate of visibility is a late (~300-500 ms), broadly distributed positive component, the P3 or P3b. Quotation withheld because this record is not cleared for redistribution. The proportion of neurons following the reported percept rose from about 20% in V1/V2 to 40% in V4/MT/MST and up to 90% in IT and STS. Quotation withheld because this record is not cleared for redistribution. Conscious words modulated late activity at 68.8% of intracranial electrode sites versus 24.4% for non-conscious words, showing that conscious access has a brain-wide impact. Quotation withheld because this record is not cleared for redistribution. Transcranial magnetic stimulation over parietal or prefrontal cortex, far from visual areas, can block conscious perception and even make a fixated stimulus subjectively disappear. Quotation withheld because this record is not cleared for redistribution. Patients with focal prefrontal lesions needed stronger stimuli to see a masked target, in proportion to how far the lesion extended into left anterior prefrontal cortex, while their subliminal performance stayed normal. Quotation withheld because this record is not cleared for redistribution. MS patients needed a longer target-mask delay before a masked stimulus became conscious. Quotation withheld because this record is not cleared for redistribution. The GNW model predicts, and simulations reproduce, strict seriality of conscious access. Quotation withheld because this record is not cleared for redistribution. Only conscious no-go signals triggered broad anterior activation into anterior cingulate, inferior and middle frontal gyrus, dorsolateral prefrontal and inferior parietal cortex. Quotation withheld because this record is not cleared for redistribution. Schizophrenic patients show impaired neural signatures of conscious access while their subliminal processing remains normal. Quotation withheld because this record is not cleared for redistribution. The review's inventory of empirical markers of conscious access is: all-or-none prefronto-parietal ignition, all-or-none amplification of sensory activation, a late global P3b, late broad-band gamma power increase, enhanced long-distance beta-band phase synchronisation, and enhanced causal coupling between distant areas including a top-down component. Quotation withheld because this record is not cleared for redistribution. conscious access conscious access Quotation withheld because this record is not cleared for redistribution. subliminal stimulus subliminal stimulus Quotation withheld because this record is not cleared for redistribution. preconscious stimulus preconscious stimulus Quotation withheld because this record is not cleared for redistribution. masking masking Quotation withheld because this record is not cleared for redistribution. subliminal priming subliminal priming Quotation withheld because this record is not cleared for redistribution. attentional blink attentional blink Quotation withheld because this record is not cleared for redistribution. selective attention selective attention Quotation withheld because this record is not cleared for redistribution. Global Neuronal Workspace Global Neuronal Workspace Quotation withheld because this record is not cleared for redistribution. ignition ignition Quotation withheld because this record is not cleared for redistribution. information integration information integration Quotation withheld because this record is not cleared for redistribution. MMN MMN Quotation withheld because this record is not cleared for redistribution. attention attention Quotation withheld because this record is not cleared for redistribution. response requirements response requirements Quotation withheld because this record is not cleared for redistribution. 68.8% / 24.4% — share of intracranial electrode sites whose late activity was modulated by conscious words versus by non-conscious words Quotation withheld because this record is not cleared for redistribution. 20% / 40% / 90% — proportion of recorded neurons whose firing followed the consciously perceived image during binocular rivalry, in V1-V2, in V4/MT/MST, and in IT/STS respectively Quotation withheld because this record is not cleared for redistribution. r²=0.96 — agreement across subjects between conscious perception thresholds estimated from objective performance and from subjective report in visual masking Quotation withheld because this record is not cleared for redistribution. 86% sensitivity and 97% specificity — accuracy of predicting non-recovery one year after traumatic coma from diffusion tensor and spectroscopic measures of white-matter integrity Quotation withheld because this record is not cleared for redistribution. 16 times — how many more dendritic spines layer-III pyramidal neurons carry in prefrontal cortex than in V1, cited as morphological support for long-distance integration Quotation withheld because this record is not cleared for redistribution. ~50% — the level to which global cerebral metabolic activity typically falls in coma and vegetative state relative to normal Quotation withheld because this record is not cleared for redistribution. 500 ms — elapsed time after which subliminal priming typically ceases to be detectable Quotation withheld because this record is not cleared for redistribution. ~300-500 ms — latency of the P3/P3b component identified as the most consistent ERP correlate of stimulus visibility Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1016/j.neuron.2011.03.018.