Neuroscience of Consciousness最新文献

In this study, we explore how the notion of meta-representations in higher-order theories (HOT) of consciousness can be implemented in computational models. HOT suggests that consciousness emerges from meta-representations, which are representations of first-order sensory representations. However, translating this abstract concept into a concrete computational model, such as those used in artificial intelligence, presents a theoretical challenge. For example, a simplistic interpretation of meta-representation as a representation of representation makes the notion rather trivial and ubiquitous. Here, as a foundational step toward understanding meta-representations, we propose a refined computational interpretation that focuses specifically on process-level representations. Contrary to the simplistic view of meta-representations as mere transformations of the first-order representational states or confidence estimates, we argue that meta-representations represent the computational processes that generate first-order representations, building on the Radical Plasticity Thesis by Cleeremans (2011). https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2011.00086.) This presents a process-oriented view whereby meta-representations capture the qualitative aspect of how sensory information is transformed into first-order representations. As a proof-of-concept of this formulated notion of meta-representation, we constructed "meta-networks" designed to explicitly model meta-representations within deep learning architectures while methodologically isolating process representations from specific sensory activations to avoid confounding effects. Specifically, we constructed meta-networks by implementing autoencoders of first-order neural networks. In this architecture, the latent spaces embedding those first-order networks correspond to the meta-representations of first-order networks. By applying meta-networks to embed neural networks trained to encode visual and auditory datasets, we show that the meta-representations of first-order networks successfully capture the qualitative aspects of those networks by separating the visual and auditory networks in the meta-representation space. We argue that such meta-representations would be useful for quantitatively comparing and contrasting the qualitative differences of computational processes. While whether such meta-representational systems exist in the human brain remains an open question, this formulation of meta-representation offers a new empirically testable hypothesis that there are brain regions that represent the processes of transforming a representation in one brain region to a representation in another brain region. Furthermore, this form of meta-representations might underlie our ability to describe the qualitative aspect of sensory experience or qualia.

Affective stimuli, such as fearful faces, are assumed to receive prioritized processing over neutral stimuli, making them easier to detect when perception is suppressed using techniques such as visual masking or binocular rivalry. Moreover, some studies suggest that fearful expressions can be processed outside of conscious awareness, as evidenced by enhanced early event-related potentials (ERPs) in response to subliminally presented fearful vs. neutral faces. This might be associated with increased detection of fear-related stimuli. However, it remains unclear whether increased cortical processing of unseen fearful faces is a necessary condition for detection advantages and whether effects are related to expression-related or low-level features of stimuli. In the present pre-registered ERP study, we addressed these questions using stereoscopic forward masking (FM). Forty-eight male and female participants were presented with fearful and neutral, intact and phase-scrambled faces. The behavioural results showed that masked fearful faces were detected better than neutral faces. Phase-scrambled faces did not show this effect, indicating that the perceptual advantage was not mediated by low-level spectral stimulus properties. ERPs elicited by consciously perceived faces showed typical expression effects in the form of enhanced occipito-temporal negativities in the time range of the N170 and the early posterior negativity (EPN). Crucially, these effects were absent for subjectively invisible faces, as corroborated by Bayesian statistics. Taken together, our results suggest that the perceptual advantage of fearful faces under dichoptic FM cannot be attributed to low-level stimulus properties. Furthermore, within this paradigm, the perceptual advantage does not coincide with the amplification of early ERPs to subjectively invisible faces, suggesting a dissociation between unconscious stimulus processing and stimulus detection.

This article presents a neuroscientific interpretation of Carl Jung's theory of archetypes and their experience in altered states of consciousness. We begin by rehearsing the Free Energy Principle and Predictive Processing as foundational frameworks that subserve and inform the thesis that follows. The following sections examine three aspects of archetypes: the affective core rooted in subcortical systems, archetypal imagery emergent in altered states such as psychedelic experiences, and archetypal stories encoded in higher cortical areas. Specifically, we propose a trilogical interplay between the high-level cortex, the low-level cortex, and subcortical/affective systems in instantiating these archetypal phenomena. We then explore how archetypes may be transmitted between individuals, developing into a collective unconscious through social learning and subsequent attunement. Throughout, we provide syntheses of Jungian psychology with contemporary neuroscience, offering testable hypotheses regarding the neurological bases of archetypal phenomena. We conclude by discussing implications for both psychoanalytic theory and neuroscientific research. By bridging these disciplines, we aim to lend construct validity to Jungian concepts and encourage further empirical investigation of archetypes and the collective unconscious.

Theoretical accounts link mind wandering with attentional and executive processes, both of which exhibit time-of-day fluctuations influenced by chronotype. While previous studies have proposed increased mind wandering at nonpreferred times of the day, these findings come from methodologically limited designs. Using ecological momentary assessment (EMA), we revisited this hypothesis and examined how mind wandering is associated with time of day and chronotype, hypothesizing that mind wandering would be more likely to occur during nonpreferred times of the day. Additionally, we took an exploratory approach and investigated previously unexplored daily fluctuations in temporal orientations of mind wandering in different chronotypes. A total of 152 participants were involved in an EMA, rendering a total of 13 001 successfully completed samples. Generalized linear and linear mixed models were employed to investigate the associations between chronotype, time of day, mind wandering, and its temporal orientations. A pronounced time-of-day dynamic was observed, pointing to a gradually decreasing probability of mind wandering over the course of the day; however, no chronotype synchrony effect was observed. Daily dynamics of the temporal orientation of mind wandering were significantly predicted by chronotype. While eveningness was associated with an increase in the proportion of future-oriented thoughts and a decrease in that of present-oriented thoughts throughout the day, the opposite was found for morningness. These findings suggest that time of day is associated with the probability of mind wandering and its temporal orientation, the latter moderated by an individual's chronotype.

It is well known that in interdisciplinary consciousness studies there are various competing hypotheses about the neural correlate(s) of consciousness (NCCs). Much contemporary work is dedicated to determining which of these hypotheses is right (or the weaker claim is to be preferred). The prevalent working assumption is that one of the competing hypotheses is correct, and the remaining hypotheses misdescribe the phenomenon in some critical manner and their associated purported empirical evidence will eventually be explained away. In contrast to this, we propose that each hypothesis-simultaneously with its competitors-may be right and its associated evidence be genuine evidence of NCCs. To account for this, we develop the multiple generator hypothesis (MGH) based on a distinction between principles and generators. The former denotes ways consciousness can be brought about and the latter how these are implemented in physical systems. We explicate and delineate the hypothesis and give examples of aspects of consciousness studies where the MGH is applicable and relevant. Finally, to show that it is promising we show the MGH has implications which give rise to novel questions or aspects to consider for the field of consciousness studies.

The role of the prefrontal cortex (PFC) in consciousness is hotly debated. Frontal theories argue that the PFC is necessary for consciousness, while sensory theories propose that consciousness arises from recurrent activity in the posterior cortex alone, with activity in the PFC resulting from the mere act of reporting. To resolve this dispute, we re-analysed an electroencephalography (EEG) dataset of 30 participants from a no-report inattentional blindness paradigm where faces are (un)consciously perceived. We performed source reconstruction on the EEG data to first establish the robustly active regions, which were then used to build the networks in the dynamic causal modelling analysis. Dynamic causal modelling was used to estimate the effective connectivity between the key contended brain regions, the prefrontal and the posterior cortices. Then, a second-level parametric empirical Bayesian model was conducted to determine how connectivity was modulated by awareness and task-relevance. While an initial data-driven search could not corroborate neither sensory nor frontal theories of consciousness, a more directed hypothesis-driven analysis revealed strong evidence that both theories could explain the data, with a very slight preference for frontal theories. Specifically, a model with backward connections switched off within the posterior cortex explained awareness better (53%) than a model without backward connections from the PFC to sensory regions. Our findings provide some support for a subtle, yet crucial, contribution of the frontal cortex in consciousness, and highlight the need to revise current theories of consciousness.

A major distinction in early visual processing is the magnocellular (MC) and parvocellular (PC) pathways. Prior work has theorized that the PC pathway more strongly contributes to conscious object recognition via projections to the ventral ``what'' visual pathway, whereas the MC pathway underlies non-conscious, action-oriented motion and localization processing via the dorsal stream ``where/how'' pathway. This invites the question: are we equally aware of activity in both pathways? And if not, do task demands interact with which pathway is more accessible to awareness? We investigated this question in a set of two studies measuring participants' metacognition for stimuli biased toward MC or PC processing. The "Steady/Pulsed Paradigm" has two conditions that present brief stimuli alongside temporally distinct luminance pedestals, thought to bias stimulus processing to either pathway. Experiment 1 was a spatial localization task thought to rely on information relayed from the MC pathway. Using both a model-based and model-free approach to quantify participants' metacognitive sensitivity to their own task performance, we found greater metacognitive efficiency in the steady (MC-biased) condition compared to the pulsed (PC-biased) condition. Experiment 2 was a fine-grained orientation-discrimination task more reliant on PC pathway information. Our results show an abolishment of the MC pathway advantage seen in Experiment 1 and suggest that the advantage in metacognitive efficiency for MC processing may hold for stimulus localization tasks only. More generally, our results highlight the need to consider the possibility of differential access to low-level stimulus properties in studies of visual metacognition.

The signals registered by our senses are inherently ambiguous. Subjective experience, by contrast, is informative: it portrays one's interpretation of the sensory environment at a time while discarding competing alternatives. This is exemplified by bistable perception, where ambiguous sensory information induces prolonged intervals of alternating unambiguous perceptual states. According to neurocomputational predictive-processing accounts of bistable perception, perceptual experiences in the recent past constitute a predictive context that stabilizes perception, while sensory information in conflict with this predictive temporal context evokes perceptual prediction errors. These perceptual prediction errors are thought to drive spontaneous perceptual switches. In this study, we compared neural correlates of perceptual conflicts induced by violations of temporal context to conflicts induced by spatial context. To this aim, we used functional magnetic resonance imaging and a bistable perception paradigm with temporal and spatial context modulation. Twenty-six healthy participants viewed intermittent presentations of ambiguous structure-from-motion stimuli either in isolation (conflict with temporal context) or embedded in a similar but unambiguous surround stimulus (conflict with spatial context). Only the anterior insula bilaterally showed brain activation associated with both types of perceptual conflict. Approximate perceptual prediction errors derived from generalized linear mixed-effects models yielded signals in the anterior insula bilaterally, the right inferior frontal gyrus, and the right inferior parietal lobe. Together, these findings point to a key role of the anterior insular cortex in detecting perceptual conflicts and thus in the construction of unambiguous perceptual experiences.

When the eyes view separate and incompatible images, the brain suppresses one image-removing it from visual awareness. A popular paradigm for doing this is continuous flash suppression (CFS). One eye views a static 'target', the other is presented with a complex dynamic stimulus which very effectively suppresses the target. Measuring the time needed for the suppressed target to break suppression as it slowly increases in contrast (bCFS) has been widely used to investigate unconscious processing and the results have generated controversy regarding the scope of visual processing without awareness. In particular, upright faces and fearful faces have been claimed to have priority access to awareness. Here, we address this controversy with a new 'CFS tracking' paradigm (tCFS) in which the suppressed monocular target steadily increases in contrast until breaking into awareness (as in bCFS) after which it decreases until it becomes suppressed again (reCFS), with this cycle continuing for many reversals. Unlike bCFS, tCFS provides measures of breakthrough thresholds as well as suppression thresholds, and the difference between breakthrough and suppression thresholds defines the important metric of 'suppression depth'. The suppression depth results over two experiments are consistent in showing no face inversion effects (i.e. no priority for upright faces relative to inverted) and no effect of emotion (no priority for fearful faces relative to happy or neutral). Given this consistent non-selectivity, we conclude that CFS elicits a strong suppression in early visual cortex at a level preceding face processing.