Theories of consciousness and psychiatric disorders – A comparative analysis

Disorders of consciousness represent an efficient way to test theories of consciousness ’ (ToCs) predictions. So far, ToCs have mostly focused on disorders of quantitative awareness such as coma, vegetative state, spatial neglect and hemianopia. Psychiatric disorders, by contrast, have received little attention, leaving their contribution to consciousness research almost unexplored. Therefore, this paper aims to assess the relation between ToCs and psychiatric disorders – that is, the extent to which current ToCs can account for psychiatric symptomatology. First, I review direct and indirect evidence linking each ToC to psychiatry disorders. Next, I differentiate ToCs based on their theoretical and methodological ground, highlighting how they distinctively address neural, cognitive, and phenomenological aspects of conscious experience and, in turn, psychiatric symptoms. Finally, I refer to one specific symptom to directly compare ToCs ’ explanatory power. Overall, Temporospatial Theory of Consciousness (TTC) appears to provide a more comprehensive account of psychiatric disorders, suggesting that a novel dimension of consciousness (i.e., form of consciousness ) may be needed to address more qualitative al- terations in conscious experience.


Introduction
Consciousness is key to our existence. As Descartes pointed out, it is the only thing we can be immediately and intuitively sure of (Descartes, 1641). For centuries, conscious experience was approached only through introspection and logical reasoning. Over the past couple of decades, however, newly developed neuroimaging techniques have allowed for a more scientific investigation of the so-called hard problemi.e., how the brain gives rise to conscious mental states (Chalmers, 1995). As a result, several neuroscientific theories of consciousness (ToCs) have been proposed. Yet, there seems to be no agreement as to how qualitative features of mental life relate to the quantitative properties of our brain (Nagel, 2007). Given the different presuppositions and empirical measures of the various ToCs' (Seth and Bayne, 2022;Northoff and Lamme, 2020), it remains indeed unclear how to compare their explanatory power regarding specific features of consciousness.
To that aim, one could primarily look at the theorical framework and/or empirical support of each ToC. Accordingly, we would expect a good theory to be able to yield testable predictions not only on basic quantitative features of consciousness (e.g., alertness or perceptual awareness), but also on more qualitative and dynamic contents thereof (Lanius, 2015). Put differently, the more a ToC succeeds in relating brain activity to the richness of both cognition and phenomenology, the more explanatory power can be assigned to it (Seth and Bayne, 2022). Disorders of consciousness may be relevant in this regard: by assessing the extent to which current ToCs can account for their symptoms, it is possible to draw reliable conclusions on ToCs' explanatory power.
Disorders of consciousness are generally defined as medical conditions that impair conscious experience quantitatively (Bernat, 2006), both in level and content (Bachmann, Hudetz, 2014). While level of consciousness can be defined as the overall state of awareness of an individual, ranging from coma to wakefulness (Laureys and Schiff, 2012), content of consciousness refers to the specific contents of awareness, including what one sees, smells, or hears (Zeki, 2003). Accordingly, consciousness comes down to sheer awareness of one's self and the surrounding environment in the here and now, with disorders of consciousness representing deficits thereof. What these conditions have in common is indeed a prominent change in awareness, that is, the extent to which one is alert and able to experience environmental/bodily stimuli.
So far, ToCs have tried to confront themselves with many such disorders, including coma, vegetative state, spatial neglect and hemianopia (Rizkallah et al., 2019;Luppi et al., 2021;Mashour et al., 2020). While carrying a major contribution to consciousness research, they may not properly address more complex and qualitative features of conscious experience, such as the dynamic interaction of perception, thoughts and feelings (Lanius, 2015). Psychiatric disorders (PDs), by contrast, may be more informative in that regard.
However, can PDs be regarded as disorders of consciousness? If we intend consciousness as quantitative awareness in the here and now, then the answer is likely negative. Psychiatric patients are indeed generally characterized by normal awareness, both in level and content. That is, they are generally alert and able to perceive and report on environmental/bodily stimuli. If, however, we intend consciousness not only as quantitative awareness but also as the dynamic experience of one's feelings, perceptions and thoughts (Lanius, 2015), PDs may very well categorize as consciousness disturbances impairing daily life.
Interestingly, the Diagnostic and Statistical Manual of Mental Disorder 5 (DSM-5) ascribes consciousness disturbances to dissociative conditions only, including dissociative identity disorder, amnesia, and derealization/depersonalization (APA, 2013). These conditions are marked by a sense of detachment from the self and/or the environment, and therefore a prominent change in the unity of conscious experience (Scalabrini et al., 2020). Although such a characterization of consciousness in terms of unity as present in the DSM-5 is more comprehensive than just quantitative awareness, it is still restricting to a certain degree. Arguably, insofar as all PDs entail relevant dysfunctions in the subjective experience of thoughts, perceptions and feelings, they can all categorize as disorders of consciousness. As such, they may provide an alternative empirical ground to test ToCs' explanatory power, one that is specifically suitable for more dynamic features of conscious experience. Accordingly, we would expect a solid ToC to succeed in relating its theoretical/methodological framework not only to disorders of quantitative awareness, but also to PDs.
Unfortunately, however, no one has tried to assess ToCs with respect to psychiatry so far. The goal of this article is therefore to conduct a preliminary investigation on how current ToCs relate to PDs, that is, the extent to which ToCs can account for psychiatric symptomatology. To this aim, I will first give a brief overview of the main ToCs in the current neuroscientific discussion. Here, I will also review direct and indirect evidence linking each ToC to PDs. Next, I will consider theoretical and methodological elements to distinguish ToCs according to how they differentially address neural, cognitive, and phenomenological aspects of consciousness. Finally, I will apply such knowledge to one specific psychiatric symptom (i.e., distorted sense of agency in schizophrenia) to directly compare ToCs' explanatory power with respect to PDs.

Higher Order Theory (HOT) and PDs
HOT maintains that being conscious of a mental state goes hand in hand with having a meta-representation of it. That is, in order for consciousness to arise, higher-order mechanisms are required. For instance, while having a first-order perceptual representation of a sound is key for an organism to respond functionally to it, that is not enough to be consciously aware of that sound. For that, higher order/metarepresentations are necessary. Those can take the form of conceptual thoughts (Lau, Rosenthal, 2011;Brown, 2015), neural computations (Cleeremans, 2007), or reality monitoring mechanisms (Lau, 2019), which are thought to be generated in frontal regions of the brain, especially in the prefrontal cortex (PFC).
Although HOT was primarily developed to account for basic perceptual conscious states, a link with more complex conscious experiences can be made. Two recent papers (Taschereau-Dumouchel et al., 2022;Brown et al., 2019) present HOT as a useful framework to understand emotional dysregulation typical of fear and anxiety. Building on empirical evidence showing that threats can trigger amygdala activation and physiological responses without individuals' conscious awareness, HOT posits that subcortical activity is not sufficient for feelings to be consciously perceived. Instead, prefrontal activity is also needed. Specifically, the PFC would re-represent subcortical inputs drawing from self-schemas as well as semantic and episodic memories, thereby generating (conscious) feelings.
Besides fear/anxiety, HOT might also relate to other PDs. If we intend meta-representations as one's ability to represent and integrate thoughts and emotions, the HOT framework might also account for some features of schizophrenia (Patniyot, 2021). Accordingly, schizophrenic subjects may no longer be able to create a coherent narrative of their own as well as other people's thoughts/emotions due to meta-representation deficits. That, in turn, may pave the way for bizarre interpretations resulting into delusions and hallucinations (Lysaker et al., 2020). Also depression can arguably categorize as a meta-representational disorder in that symptoms such as ruminative thinking relate to an increased focus on negative aspects of the own self (Northoff, 2007(Northoff, , 2016a. Such an enhanced self-focus seems also to positively relate to PFC activity, therefore in line with HOT's predictions (Cooney et al., 2010;Grimm et al., 2009;Lemogne et al., 2012).

Global Neuronal Workspace Theory (GNWT) and PDs
GNWT discriminates between conscious and non-conscious mental states based on their "global availability" to a number of cognitive processes, including attention, memory, and verbal report. Accordingly, the more the information of a state is globally available, the more that state can be consciously accessed. On a neural level, this results from the broadcasting of sensory inputs within an anatomically widespread workspace seated in prefrontal regions (Mashour et al., 2020). Therefore, like HOT, GWNT posits that the elaboration of a stimulus in early sensory cortices is not sufficient by itself to render it conscious. Two additional mechanisms supported by prefrontal activity are indeed required: broadcasting and ignition. Broadcasting refers to how populations of pyramidal cells in frontal regions receive bottom-up and transmit top-down information to areas specialized in multiple domains, including memory, attention, and motility. Only in this way can information be "globally available" and, thus, conscious. Ignition, on the other hand, simply refers to the sudden and selective activation of a specific subset of such pyramidal cells, serving as a starting point for the just-described broadcasting process. Berkovitch et al.'s (2017; papers are key resources in relating GNWT to PDs. Based on several lines of evidence, the authors suggest that schizophrenia is a disorder primarily affecting explicit (rather than implicit) cognitive processing (Berkovitch et al., 2017;Huddy et al., 2009). As such, it produces deficits in the global availability of information without simultaneously affecting subliminal processing. Psychotic individuals would therefore present selective deficits in the conscious access and manipulation of information. These, in turn, are thought to originate from dysregulations in either top-down attentional amplification or bottom-up sensory signaling (Sergent et al., 2005).

Predictive Processing Theory (PPT) and PDs
PPT posits that consciousness originates from the interplay between top-down predictions and bottom-up sensory signals (Hohwy, 2013). The brain is accordingly viewed as a machine implementing a process of prediction error minimizationthat is, minimizing the discrepancy between top-down predictions and bottom-up information (Fletcher, 2020). Conscious mental states would then arise from the brain's "best guess" of the causes of sensory stimulation (Friston, 2010), with the type of experience depending on the nature of the predictions. For example, proprioceptive and visual consciousness both depend on conditional predictions of the sensory consequences of motor actions, whereas conscious emotional states arise from predictions of interoceptive nature.
Explicit connections between PPT and psychiatry can only be found in Seth et al. (2012) and Critchley and Garfinkel (2017). A more general link between predictive processing and PDs is instead much broader (for an overview, see Friston, 2017). The literature proliferates with evidence on predictive mechanisms and various psychiatric conditions such as somatic symptom disorder, depression and schizophrenia. For instance, somatic symptom disorder is a psychiatric condition characterized by excessive feelings, thoughts, or behaviors toward alleged physical symptoms. According to PPT, it results from excessively strong and negatively biased interoceptive predictions that alter bottom-up bodily signals, thereby amplifying the unpleasantness attached to them (Seth et al., 2012). As for depression, resting-state functional MRI data and computational modeling indicate altered bottom-up and top-down information flow in sensory and motor regions (Ray et al., 2021). In line with PPT, depression has additionally been proposed to originate from distorted (predictive) inferences regarding allostasis, whereby the brain becomes insensitive to its sensory context (Barrett et al., 2016). Finally, auditory verbal hallucinations (AVH) in schizophrenia have also been explained as disruptions in predictive mechanisms, especially those governing inner speech production (Vicente, 2014). Accordingly, schizophrenic individuals wrongly ascribe the source of their inner speech to external sources due to aberrant predictive processing (Mondino et al., 2015(Mondino et al., , 2016Humpston et al., 2019).

Recurrent processing theory (RPT) and PDs
RPT was first formulated by Lamme (2006) after experiments on visual awareness. The theory maintains that the first stream of feedforward sensory processing is not conscious, for consciousness arises only when feedback information interacts with those same neurons activated during the initial stream (Fahrenfort et al., 2007).
Given RPT's restricted application on basic perceptual forms of consciousness (e.g., visual awareness), adapting its theoretical framework to PDs turns out problematic. While HOTs, GNWT, and PPT frameworks are more or less relatable to cognitive, affective and behavioral aspects of PDs, RPT is arguably far from that. Considering also the absence of previous literature linking RPT and PDs, elaborating on a connection between the two would be too much of a speculation. Hence its exclusion from the analysis.

Information integration theory (IIT) and PDs
Unlike any other ToC seen so far, IIT starts from experience itself and makes the link with brain activity only at a second stage. While ToCs such as HOT and GNWT focus on access consciousness, i.e., the brain mechanisms associated with accessing the contents of experience, IIT focuses primarily on phenomenological consciousness, i.e., what it feels like to be conscious (Block, 2005). IIT starts from five universal axioms (i.e., intrinsic existence, composition, information, integration, exclusion) assumed to be true for every phenomenological experience (Tononi et al., 2016), and posits that each physical system that satisfies those axioms causally entails consciousness. In other words, consciousness can be viewed as the necessary effect of the structure of a physical system that meets the five axioms. Crucial to the functioning of the system is information integration. That is, the more information integrated by the system, the higher the level of consciousness entailed by it. This can be measured through the mathematical index Φ or the Lev-Zempel Complexity (LZC). Of note, a proxy of Φ has yielded low values in coma, medium in minimal conscious state, and maximal during wakefulness (Tononi et al., 2016;Casali et al., 2013), therefore in line with IIT predictions.
Besides addressing quantitative aspects of consciousness such as level/state, IIT claims to potentially explain qualitative features too. That is, depending on how the elements in the physical system are causally structured, different qualitative experiences arise. In the case of humans, the physical system is the brain, and the elements are the pattern of neuronal firing/connections. Taking visual (spatial) experience as one example, the cause-effect structure has been related to grid-like neural patterns in early visual cortices (Huan and Tononi, 2019).
Given such a prominent focus on phenomenological features of consciousness, we would expect IIT to relate to the phenomenology of PDs to a greater extent than the other above-described ToCs. While true in principle, this remains yet to be established. Early evidence linking the IIT framework to PDs concerns schizophrenia (Tononi and Edelman, 2000), here boiled down to a disorder of information integration based on the following argumentation. Assuming that the unity of cognition/perception stems from coherent re-entrant neural interactions among widely distributed networks (rather than within single regions), psychotic symptoms would result from disruptions in such mechanisms. Building upon evidence from binocular rivalry (Srinivasan et al., 1999), the authors go on to claim that similar dynamics may apply not only to the visual system but also to other subdivisions of the thalamocortical system, including those thalamic and cortical regions allegedly involved in the pathophysiology of schizophrenia.
Along those lines, a robust body of research on thalamic-generated oscillations in schizophrenic populations has gained increasing attention over the past decade (Ferrarelli and Tononi, 2011). Of note, many studies converge in finding abnormal spindle activity (especially during sleep) in patients as well as first-degree relatives (Manoach et al., 2016;Ferrarelli et al., 2007;D'Agostino et al., 2018). Given that thalamic oscillations cue information integration (Pinault, 2011), these results are thought to partly corroborate the IIT framework.
Lastly, deficits in information integration have also been linked to depression (Brzezicka, 2013). Here, aberrant information integration would be manifest in the abnormal pairing between the default mode network (DMN) and the frontoparietal network (FPN). Accordingly, the typical DMN hyperactivity seen in depression is thought to result in reduced FPN activity, causing impaired information processing and, in turn, cognitive deficits (Brzezicka, 2013).

Temporo-spatial theory of consciousness (TTC) and PDs
TTC was first developed by Northoff and Huang in 2017 (see also Northoff and Zilio 2022a and b for recent updates). It relies on the assumption that the brain constructs its own intrinsic time and space as distinct from the extrinsic time and space of the environment (Northoff, 2018). Crucially, TTC posits that subjective experience exhibits spatiotemporal properties (i.e., subjective time and space) which tightly related to those of the resting-state brain (i.e., regions topography and neural timescales). In other words, the way in which conscious experience unfolds in subjective space and time mirrors the spatiotemporal patterns underlying spontaneous brain activity (Northoff et al., 2020a and2020b).
Such a novel theoretical perspective carries innovative methodological implications. While all the above ToCs exclusively focus on stimulus-induced brain activity, TTC also emphasizes the role of spontaneous and pre-stimulus activity, including their interaction with stimulus-induced activity. Accordingly, four different mechanisms are thought to underly conscious experience: (1) Temporo-spatial nestedness refers to the organization of the various spatial and temporal brain scales during its resting-state. Rather than operating as independent units, they are contained (or nested) within each other such that different organizations entail different conscious experiences.
For a link between spatial organization (i.e., brain topography) and level of consciousness, see Tanabe et al. (2020). Similarly, for a connection between temporal organization (i.e., brain timescales) and level of consciousness, see Zilio et al. (2021).
(2) Temporo-spatial alignment refers to how the brain adapts its spontaneous activity to integrate upcoming stimuli. Different brain regions adapt their spontaneous activity to different extents depending on their intrinsic neural timescales. Multimodal regions such as the DMN exhibit longer timescales, whereas unimodal regions like primary sensory cortices have shorter timescales (Golesorkhi et al., 2021a and2021b;Wolff et al., 2022). These latter are crucial for maintaining normal levels of consciousness as their shorter timescales allow the brain to timely align with external inputs (Zilio et al., 2021).
(3) Temporo-spatial expansion refers to the actual interaction between pre-stimulus activity and stimulus-induced activity. The interaction is assumed to be non-additive, meaning that the spatiotemporal features of pre-stimulus activity are carried over and expanded during the post-stimulus interval (Huang et al., 2015;Wainio-Theberge et al., 2022;Wolff et al., 2022).
(4) Temporo-spatial globalization refers to the post-stimulus interval only, i.e, stimulus induced-activity. In keeping with ToCs like HOT and GNWT that focus on access consciousness, it describes brain activity patterns whereby the contents of consciousness are accessed.
In sum, (1) temporospatial nestedness provides the contents-free background of consciousness, as determined by the spatiotemporal dynamics of spontaneous brain activity. The remaining mechanisms (2,3,4) focus on how spontaneous activity interacts with stimulus-induced activity to produce the actual contents of consciousness, thereby shaping subjective experience.
While introducing new concepts and tools for measuring spatiotemporal features of stimulus-free spontaneous brain activity, TTC still embraces elements of the other ToCs. For instance, the stimulus-related neurocognitive mechanisms postulated by functionalist ToCs such as GNWT and PPT still cohere with the TTC framework, but they are now considered in light of stimulus-free spontaneous activity see also Fig. 3). Moreover, the short-term input integration as postulated by IIT (100-300 ms as in the alpha and theta frequency range) is now incorporated by TTC into longer timescales (delta and slower frequencies) (Northoff and Zilio, 2022a).
Interestingly, not only has the TTC framework proven useful to explain quantitative disruptions in conscious experience (Tanabe et al., 2020;Zilio et al., 2021), but it also seems to address more (qualitative) phenomenological alterations, including those occurring in PDs. Considering schizophrenia as an example, evidence points towards altered spontaneous activity both in space and time (Robinson et al., 2016;Wolff et al., 2021). On the spatial level, schizophrenic patients exhibit reduced anticorrelation between the DMN and the central executive network (CEN) (Robinson et al., 2016). Phenomenologically, this translates to a blurry distinction between internally and externally generated stimuli, as reflected in positive symptoms such as delusions and hallucinations. On the temporal level, there is evidence of a disbalance between slower frequencies (delta and theta) and faster frequencies (beta and gamma) (Northoff and Duncan, 2016), with the power shifted towards the long-phase durations of the former. This has been related to a pronounced focus on the self and detachment from the environment (Northoff et al., 2021; Northoff and Gomez-Pilar, 2021). Further, decreased cross-frequency coupling between frequency bands (Northoff and Duncan, 2016) is thought to prevent the integration of faster frequencies into slower frequencies, which phenomenologically translates into difficulty integrating environmental stimuli into a coherent unitary representation ("perceiving the world as snapshots"). Schizophrenic individuals additionally exhibit weak rest-to-task changes in brain activity, which points toward the inability to align spontaneous activity to environmental stimuli Wolff et al., 2021). Intriguingly, Wolff et al. (2019) found that similar dynamics apply to depression, where pre-stimulus activity changes are carried over to task-related activity, leading to reduced reactivity to external stimuli and, thus, cognitive deficits. Lastly, further evidence linking TTC with PDs comes from bipolar disorder, where the phenomenology of mania and depression has been related to increased and decreased resting-state neural variability, respectively (see also Discussion;Northoff et al., 2018).

Overview: comparing ToCs with respect to PDs
The above has shown how current ToCs differ in the way they can account for conscious experience and, in turn, for PDs. While some mainly address neural and cognitive aspects, others better capture phenomenological elements too (see Fig. 1 for an overview). Understanding why requires a deeper examination of ToCs' explanatory targets. Accordingly, I here differentiate between functionalist, causalstructure, and structuralist ToCs. While a description of the first two can be found in Doerig et al. (2019), the latter has been specifically added to characterize TTC.

Functionalist theories
HOTs, GNWT and PPT can be regarded as functionalist ToCs (Doerig et al., 2019). As such, they try to explain consciousness in terms of its function, including applying higher-order representations on lower-order representations (HOT), accessing information stored in a global workspace (GNWT), or using prior information to predict upcoming stimuli (PPT). Crucially, functionalist ToCs do not aim to establish a direct link between phenomenology and neural activity. That is, rather than explaining why different conscious experiences feel differently, they seek to determine the neuro-cognitive mechanisms that render an experience conscious as such. In other words, instead of being interested in why the feeling of seeing a house is different from that of smelling a rose, functionalist ToCs focus on what makes it possible to be aware of either. Consciousness is therefore viewed as an underlying function cutting across different experiential domains (i.e., perceptions, feelings, thoughts, etc.), which allows us to access and manipulate information more efficiently by being aware of it. Accordingly, conscious experience comes down to down to quantitative awareness, i.e., the extent to which one is alert and aware of specific stimuli. As such, functionalist ToCs can only account for neural and cognitive mechanisms of consciousness, leaving qualitative experience (i.e., phenomenology) unaddressed.
Being PDs conditions where consciousness is primarily altered in its qualitative (rather than quantitative) component, functionalist ToCs may account for their symptoms only to a limited extent. HOT, for instance, may help with anxiety or depression by emphasizing the role of high-order representations and, thus, of prefrontal activity over lowerorder subcortical activity, which makes patients more aware of certain contents of experience (e.g., worry and sense of worthlessness). However, it cannot explain why being panicked feels different from being stuck in ruminative thinking. Likewise, GNWT might help understand cognitive deficits in schizophrenia in terms of disruptions in the conscious access to information, but it cannot describe what it feels like not to be able to consciously integrate stimuli from the environment. Lastly, PPT may very well be a good framework to explain symptoms such as delusions and hallucinations on a neurocognitive level, where top-down priors heavily shape bottom-up sensory signals resulting in patients being aware of things that in fact are not there. Yet, it does not provide any information on the experiential component of positive symptoms.

Causal-structure theories
RPT and IIT can be regarded as causal-structure ToCs (Doerig et al., 2019). Unlike functionalist ToCs, they attempt to causally relate phenomenological features of consciousness to specific patterns (i.e., structures) of brain activity. Accordingly, each conscious experience can formally be traced back to a specific neural pattern that is thought to be the cause of that very experience. Thereforeat least in principlecausal-structure ToCs can also address the phenomenological level of consciousness (in addition to the neural and the cognitive level).
However, RTP has fallen short in that regard, being able to account only for a restricted scope of conscious experience (see 2.4). As such, it cannot be considered a valuable tool to explain PDs. IIT, by contrast, appears more promising. Its well-structured theoretical framework seems more suitable for testing empirical hypotheses on PDs, some of which can already be found in Tononi and Edelman (2000). However, its mathematical indices like Φ or LZP are still far from pinpointing even the most basic form of experience (Haun and Tononi, 2019), and much less those characterizing psychiatric conditions. Moreover, IIT has only focused on task-related activity in a limited temporal range, namely that occurring within 100-300 ms after stimulus presentation (Kent and Wittmann, 2021;Northoff and Zilio, 2022a). While suitable for explaining phenomenological experiences restricted to short-time intervals, this approach leaves unexplained the temporal relation among such experiences on longer timescales (from seconds to minutes to hours) -that is, our stream of consciousness.
In sum, while formally able to address all three levels of consciousness, causal-structure ToCs still show empirical and methodological shortcomings.

Structuralist theory
One novelty of the present paper is to characterize TTC as a structuralist ToC, for it links conscious experience to the spatiotemporal pattern (or structure) of spontaneous brain activity. It is not a causal ToC as it does not posit any causal relationship between the two. By contrast, it argues in favor of a necessary connection between spontaneous brain activity and conscious states, which is based on space and time as their "common currency" (Northoff, 2018;Northoff et al., 2020a and2020b).
To draw an analogy, in the same way that the combination of two molecules of hydrogen and one of oxygen (H 2 O) necessarily entails water, TTC posits that the spatiotemporal patterns underlying spontaneous brain activity necessarily entail just as many conscious states characterized by analogous spatiotemporal dynamics. Crucially, the relation between H 2 O and water is not causal since one is not needed for the other to exist. In fact, they can be seen as flip sides of the same coin. Likewise, spontaneous brain activity and conscious states are not causally linked as they represent two sides of one "common currency", namely spatiotemporal dynamics.
In sum, considering the attempt to directly link neural activity to phenomenology, TTC can formally address all levels of conscious experience (as causal-structure ToCs do). Such theoretical assumptions are supported by a set of novel empirical measures for assessing spatiotemporal dynamics on both the neural and the phenomenological levels. These include global signal topography (GST) for spatial neural features (Zhang et al., 2019;Lu et al., 2022;Scalabrini et al., 2020), and power spectral density, autocorrelation window (ACW) and power law exponent (PLE) for temporal neural features (Rostami et al., 2022;. For phenomenal features, however, empirical measures are less, and include the Scale for Space and Time Experience in Psychosis (STEP) (Arantes-Goncalves et al., 2022) and the measurement of thought dynamic (Rostami et al., 2022).
Overall, among the current ToCs, TTC seems to be better suited to capture the different layers of consciousness (neural, cognitive, phenomenological), according to both empirical results and theoretical/ methodological frameworks. Arguably, assuming identity (rather than causality) between brain patterns and phenomenological experiences has allowed TTC to develop suitable empirical measures to better address the qualitative side of experience, as compared to IIT and RPT. This, in turn, is reflected in a much stronger attempt by TTC to link consciousness research to PDs.
To further substantiate this conclusion, I now refer to one specific . Formally = the extent to which a ToC can potentially address a specific level of conscious experience based on its theoretical/ methodological framework. Evidence = the extent to which a ToC has yielded results for that specific level of conscious experience. Symbols → "/" = absent; "þ " = moderate; "þ þ" = convincing. Accordingly, functionalist ToCs like HOT, GNWT, and PPT have a higher explanatory power on the neuro-cognitive level, but not on the phenomenological level. Instead, causal-structure and structuralist ToCs like IIT and TTC seem to address all three levels (at least formally).
psychiatric symptom (distorted sense of agency in schizophrenia) as I believe it to duly mirror whatup to this point -I have been trying to address only on a more general level, that is, the extent to which current ToCs can account for psychiatric symptomatology.

Distorted sense of agency (SoA) and current ToCs
Schizophrenic individuals experiencing distorted SoA (also referred to as alien control) describe their thoughts or movements as controlled by external agents (Frith, 2005), resulting in delusions of thought insertion and/or motor control. In the former, patients believe that thoughts that are not their own have been inserted into their minds (Mullins and Spence, 2003). In the latter, they are instead convinced that external sources exert direct control over their movements (Mellor, 1970).
As shown above (see 2.7), differentiating between the neural, cognitive, and phenomenological levels of conscious experience is key to assessing ToCs' explanatory power. Hence, the same criteria are here applied with respect to distorted SoA in schizophrenia (see Fig. 2 for an overview).

Cognitive level
HOT argues that, in addition to first-order sensory representations, higher-order representations are key for conscious experience. In this sense, distorted SoA might result from disruptions in higher-order mechanisms contributing to feelings of ownership over thoughts and actions. There are two alternative ways whereby this might take place.
(1) While first-order (unconscious) sensory processing properly functions, higher-level representations can be disrupted. If so, experimental studies where SoA is probed through implicit measures should yield similar results between schizophrenics and healthy controls. Conversely, paradigms where subjects are asked to make explicit judgments on their performances should bring about differences between groups. Despite some evidence in this direction (Voss et al., 2017), most of the studies converge on SoA alterations at the implicit level too (Gallagher, 2007;Haggard, 2017). Alternatively (2), it could be that first-order representations are disrupted, and that higher-order mechanisms re-represent what is already dysfunctional. However, this remains yet to be established.

Neural level
HOT emphasizes the role of the PFC in generating higher-order representations. Thus, based on alternative (1), we might expect schizophrenic subjects with alien control to show normal implicit processing in early sensory cortices and abnormal processing in the PFC. While distorted PFC activation has long been demonstrated in schizophrenia (Orellana and Slachevsky, 2013;Bygrave et al., 2019;Giraldo-Chica et al., 2018), there is no agreement on it being a sign of meta-representational deficits. Besides, early sensory processing has also been shown to be impaired in schizophrenia (Hamilton et al., 2019;Ergen et al., 2008;Amedeo et al., 2022).

Phenomenological level
Being a ToC with a focus on access consciousness, HOT has little-tono phenomenological explanatory power (see 2.7). Indeed, even if we assumed that HOT could fully explain alien control both on the neural and cognitive level, that would only explain how patients become aware of their delusions, not what it feels like to lose agency over thoughts and/ or movements.
In sum, as a functionalist ToC (see 2.7), HOT can only generate testable neurocognitive hypotheses, leaving the phenomenological side unaddressed.

Cognitive level
GNWT maintains that consciousness arises from the global availability and accessibility of information. Accordingly, disorders in conscious experience would be due to impairments in, for example, information broadcasting. Such impairments may in turn originate from cognitive deficits underlying the storing and broadcasting of information, including working memory and attention. Interestingly, working memory deficits are one putative mechanism responsible for thought insertion. The idea is that psychotic individuals are not able to piece together the internal chain of events leading to the emergence of one thought. The thought is therefore perceived as coming "out of nowhere" and interpreted as having been "inserted" by external forces (Martin and Pacherie, 2013). Deficits in attention amplification might also contribute to less global information availability (Berkovitch et al., 2017). Remarkably, attentional deficits seem to be related to poor self-monitoring, which plays a key role in distorted SoA symptomatology (Stirling et al., 2001;Jones and Fernyhough, 2007;Cox et al., Fig. 2. The extent to which current ToCs target the three levels of distorted SoA in schizophrenia. Neural level = brain activity patterns underlying distorted SoA symptomatology, as measured by neuroimaging techniques, including EEG and fMRI. Cognitive level = psychological mechanisms such as attention, memory, and perception that are thought to contribute to delusions of SoA. Phenomenological level = subjective experience of the symptom, i.e., what it feels like to be controlled by external forces. Though inevitably linked together, these levels are not to be seen hierarchically as they represent three different standpoints whereby conscious experience can be approached. For the meaning of "Formally", "Evidence", and symbols "+ ", refer to Fig. 1. The output is analogous to that of Fig. 1: IIT and TTC can formally address all levels of the symptom, but TTC has a stronger empirical ground. 2014).

Neural level
In the GNWT's framework, the PFC is crucial as it contains a great density of those pyramidal neurons thought to implement global information broadcasting. PFC alterations have been extensively linked to attention and/or working memory deficits in schizophrenic populations (Orellana and Slachevsky, 2013;Bygrave et al., 2019;Giraldo-Chica et al., 2018). Although so far no studies have connected global information broadcasting, PFC activity and alien control in schizophrenia, it is still plausible that they might share common underlying mechanisms. Of note, the only study directly comparing the neural basis of thought insertion and alien (motor) control indeed found prefrontal alterations during both (Walsh et al., 2015).

Phenomenological level
Like HOT, GNWT is a theory of access consciousness, meaning that it poorly addresses phenomenology. Accordingly, although distorted SoA may be understandable in terms of global information deficits, that would again only account for neurocognitive mechanisms (e.g., attention/working memory underpinned by abnormal prefrontal activity) whereby delusional experiences access patients' threshold of awareness.

Cognitive level
PPT has long been applied to psychiatric symptoms, including different models to explain distorted SoA in schizophrenia. The Comparator Model (CM) was a first attempt in that regard (Frith et al., 2000). Essentially, the CM maintains that normal SoA arises from a successful comparison between the predicted outcome of intended motor plans and the actual outcome. When these two align, agency is attributed to the self; otherwise, agency is attributed elsewhere (as in the case of schizophrenia). Given its limited focus on sensory-motor predictive mechanism, the CM was subsequently extended to include cognitive factors too. Hence the Multifactorial Weighting Model (MWM), which incorporates sensory-motor mechanisms into higher-order cognitive judgments of agency (Synofzik et al., 2008). Both models have been extensively used to explain positive symptoms such as hallucinations and delusions of control (Sterzer et al., 2018;Humpston et al., 2019;Sterzer et al., 2016;Gerrans, 2015).

Neural level
Besides providing cognitive accounts, PPT has notably provided many neural accounts of distorted SoA, with evidence converging on one putative mechanism, i.e., increased inferior parietal activity (Blakemore and Frith, 2003;Lafargue, Franck, 2009;Lafargue and Sirigu, 2006;Walsh et al., 2015). Accordingly, successful predictions are thought to arise from the top-down inhibition exerted by frontal regions over inferior parietal cortices. Here, the supplementary motor area (SMA) is thought to send feedforward predictions to the inferior parietal lobule (IPL), thereby regulating its activation. When feedforward predictions cohere with the actual sensory input, IPL activity is attenuated by the SMA and SoA arises. Conversely, a mismatch between predictions and sensory inputs results in increased IPL activity and reduced SoA. Of note, enhanced IPL activity has been directly linked to experiences of distorted SoA such as auditory verbal hallucinations (Mondino et al., 2015) and alien control (Walsh et al., 2015).

Phenomenological level
As compared to HOT and GNWT, PPT provides a more accurate and empirically supported neurocognitive framework to understand distorted SoA in schizophrenia. Nevertheless, it does not differ in terms of its phenomenological explanatory power. Even if distorted SoA could be fully explained in terms of disrupted predictive processes, that would not automatically allow discriminating qualitative features of the symptom. For that purpose, we would need additional theoretical assumptions such as a direct link between brain activity and subjective states (as IIT and TTC propose).

IIT and distorted SoA
As discussed before (see 2.7), causal-structure ToCs seem to address the phenomenological level too. I here decided not to include RPT as it has only been applied to the neural level of visual awareness. Inferring how it may account for the cognitive and phenomenological aspects of distorted SoA is therefore overly ambitious. I thus consider IIT only.

Cognitive level
IIT posits that schizophrenic symptoms emerge from information integration deficits. In this sense, distorted SoA might be explainable in terms of impaired information processing involving dysfunctions in multiple cognitive domains, including perception, memory, and attention. While the literature abounds with evidence in this direction, no explicit link with the IIT framework has been made so far.

Neural level
According to IIT, deficits on the cognitive level are underpinned by disruptions in the neural mechanisms underlying information integration. Regarding distorted SoA, one such mechanism can be altered thalamocortical oscillatory patterns as shown by patients and firstdegree relatives (Manoach et al., 2016;Ferrarelli et al., 2007;D'Agostino et al., 2018), which remains yet to be linked with SoA. Alternatively, integrity in the SoA may deeply rely on information integration within the somatosensory cortex, as recently shown by Piras and colleagues (2020).

Phenomenological level
IIT maintains that it is possible to relate every conscious experience to the structure of the physical substrate being its cause (i.e., the brain). Thusat least in principle -IIT may provide a direct link between neural activity and subjective experience in distorted SoA. As shown above (see 2.7), however, IIT is still far from being testable on complex forms of conscious experience. Additionally, it is restricted to short timescales only, which limits the comprehension of a symptom like distorted SoA which requires consideration of longer timescales too (Wen, 2019).
In sum, IIT can formally address all levels of the symptom (neural, cognitive, phenomenological), but only with limited theoretical and empirical bases.

TTC and distorted SoA
TTC is a structuralist ToC (see 2.7). I start here with the neural level, as it allows a better comprehension of the other two.

Neural level
TTC posits that the temporospatial features of spontaneous brain activity are key to explaining conscious mental states (see 2.6). Distorted SoA can thus be understood in terms of altered brain spatial topography and temporal dynamics during its resting state. On the spatial level, there is evidence of reduced DMN-CEN anti-correlation, as well as reduced anti-correlation between sensory networks and associative networks, pointing towards a blurry distinction between external and internal focus (Robinson et al., 2016;Yang et al., 2017). On the temporal level, the abnormally prolonged intrinsic neural timescales shown by schizophrenic subjects (see 2.6) might relate to excessive self-focus, which prevents them from properly aligning with the environment (Northoff and Duncan, 2016;. Increased 'noise' in stimulus-free (as compared to stimulus-induced) brain activity may also be a contributing factor .

Cognitive level
The cognitive level is usually studied through stimulus-induced experimental paradigms. As said before (see 2.7), while emphasizing the importance of the resting-state, TTC considers stimulus-induced mechanisms too. Specifically, it considers cognitive symptoms such as memory/attention/perception deficits in light of resting-state spatiotemporal dynamics (i.e., brain topography and timescales). For instance, TTC agrees that distorted SoA may be explainable as proposed by PPTthat is, in terms of predictive-processing alterationsyet it argues that they occur as a result of aberrant patterns in the brain spontaneous activity including reduced DMN-CEN anticorrelation (Yang et al., 2017), and abnormal temporal dynamics including abnormally long intrinsic neural timescales , Wengler et al., 2020) (see Fig. 3). However, the precise mechanisms whereby this would take place have not been precisely outlined yet.

Phenomenological level
It is on the phenomenological level that TTC exhibits the strongest explanatory power among current ToCs. The idea of a "common currency" between neural and phenomenological features in terms of spatiotemporal dynamics seems to allow TTC to directly relate subjective experience to resting-state brain activity (see 2.7). In the case of distorted SoA, TTC postulates that altered brain topography and temporal dynamics directly translate into altered (subjective) experience of space and time. For instance, reduced DMN-CEN anticorrelation and abnormally prolonged intrinsic neural timescales are mirrored into a blurry distinction between internal/external focus , as well as into a fragmented experience of time (Northoff and Duncan, 2016;Northoff, 2022). This, in turn, would not allow schizophrenic individuals to properly differentiate between internally-and externally-generated inputs, resulting in delusions of agency (see Fig. 3).
In conclusion, TTC appears to be the ToC that most comprehensively addresses each level of distorted SoA symptomatology.

Discussion
This paper compared current ToCs based on their explanatory power with respect to PDs as examples of dynamic alterations in conscious experience. One main conclusion is that different theoretical assumptions and methodological tools entail differences in the degree to which ToCs can account for neural, cognitive and phenomenological features of consciousness (see 2.7). Some theories, like GNWT, PPT and HOT, can well explain neural and cognitive aspects, but fall short in considering the phenomenological side. Others, like IIT and TTC, do seem to address all three levels, but still bear some limitations.
Overall, the above comparative analysis yielded a higher explanatory power for TTC, as witnessed by the promising results emerged in recent years. This can be attributed to three key aspectstwo methodological and one more theoretical. First, the emphasis on spontaneous brain activity as featured by its spatiotemporal structure which strongly shapes task-related activity. Second, the consideration of both shorter and longer timescales in the understanding of consciousness. Third, the idea of a "common currency" between brain activity and subjective experience in terms of shared spatiotemporal dynamics. As compared to the other ToCs, TTC therefore seems to provide a wider and more comprehensive framework to grasp the changes in conscious experience occurring in PDs. This carries major implications for how we view consciousness, extending its characterization to a third dimension besides the already-known level of consciousness and content of consciousness that is, form of consciousness (Northoff, 2013;Northoff and Lamme, 2020).
To date, consciousness has been predominantly considered according to its level and/or content (see Introduction). This distinction mainly serves a quantitative conceptualization of consciousness in terms of 'how much' we are aware (level) and 'what' we can be aware of (content) in the here and now. Howeveras said in the introductionif we agree that consciousness goes beyond in-the-moment quantitative awareness, an additional characterization may be needed. Hence form of consciousness, referring to the way in which the contents of experience are organized and structured in space and time (Northoff, 2013;Northoff and Lamme, 2020). Crucially, this new dimension of consciousness may Fig. 3. How TTC accounts for distorted SoA considering the three levels of the symptom (neural, cognitive, phenomenological). On the neural level, TTC postulates altered spatiotemporal features during stimulus-free brain activity (e.g., reduced DMN-CEN anticorrelation). These alterations are carried over to stimulusrelated activity, thereby shaping it and leading to cognitive dysfunctions (e.g., aberrant predictive processing). This, in turn, leads to a disruption in the contents of experience (e.g., self-generated movements misperceived as externally-generated). Crucially, this phenomenological experience entails a subjective sense of space and time which directly relates to space and time as measured in spontaneous brain activity ("common currency"). For instance, reduced resting-state DMN-CEN anticorrelation directly relates to confusion between internal and external focus. Such restingstate dynamics determine how cognitive mechanisms process external/internal inputs, thereby leading to misattribution of agency. If spontaneous activity is characterized by unbalance between neural networks and time scales (as in the case of schizophrenia), then external/ internal stimuli cannot be properly processed through cognitive mechanisms such as predictive coding, attention, working memory and perception. As a result, a self-generated movement is misperceived as being controlled by an external force, leading to a subjective feeling of distorted SoA (see also Discussion). help better address qualitative (rather than quantitative) aspects of experience. Understanding how requires answering the two following questions.
(1) What is precisely meant by form of consciousness? Simply put, form of consciousness is a dimension of consciousness aimed at directly linking brain activity to qualitative experience. According to TTC, this link is provided by spatiotemporal dynamics (see 2.6, 2.7), namely space and time as measured within the brain, and space and time as subjectively experienced. Specifically, TTC emphasizes the role of spontaneous brain activity in shaping subjective experience. Form of consciousness, thus, is also mirrored in the brain's resting-state topographies (space) and timescales (time), which directly shape space and time as subjectively experienced. The neural level and the phenomenological level are therefore equally relevant when referring to form of consciousness, as it simultaneously encompasses both levels as flip sides of one "common currency" (see 2.6, 2.7).
(2) Why "form" as distinguished from "level" and "content"? While level and content alone may only account for quantitative aspects of conscious experience, form attempts to address qualitative features too. Key in this regard is how space and time are subjectively experienced. Accordingly, instead of seeing consciousness and its contents as isolated blocks, considering how such contents are organized and structured in subjective space and time would help better discriminate among qualitative experiential nuances (see Fig. 4).
In sum, form of consciousness refers to the resting-state spatiotemporal structure (i.e., brain topographies and timescales) whereby external stimuli are incorporated, processed and, thus, experienced. Differently put, spontaneous brain activity would provide a 'spatiotemporal structure' (or form) according to which external/internal stimuli are incorporated and processed, thereby determining their experiential connotation. To draw an analogy, in the same way as Immanuel Kant claimed that all conscious representations are structured in space and time as our primary and only forms of intuition (Kant, 1781(Kant, /, 1998, likewise, TTC claims that space and time as within spontaneous brain activity determine and shape our experiential world. However, while Kant conceived space and time as abstract and immutable forms equally present in all human beings, TTC brings space and time back to the natural world, namely to the brain. As such, they can vary across individuals resulting in differences in conscious experience. Crucially, not only do such differences involve slight changes in the subjective experience of space and time reflecting normal individual variability, but they may also account for more extreme experiences, including psychiatric symptoms. Being PDs conditions where quantitative awareness is mostly preserved both in level and contentpsychiatric patients are indeed generally alert and without any full-blown quantitative perceptual deficitform of consciousness may therefore provide a better framework to understand their phenomenology, as compared to level and content of consciousness alone (see Fig. 5).
Distorted SoA in schizophrenia is a case in point (see Fig. 4). Here, quantitative features of awareness are mostly unaltered: patients are normally alert and able to perceive and report on bodily/environmental stimuli. In other words, the level and contents of experience are quantitatively intact. Those patients can indeed see and monitor their body moving around without missing any perceptual detail of it (unlike in disorders of quantitative awareness such as hemianopia). Nonetheless, they feel that they do not have ownership over their movements. Since Here, the contents of consciousness are strictly dependent upon the level of consciousness. Being in a deep coma, for instance, does not allow one to experience anything at all, as opposed to wakefulness, where the contents of experience are well defined. This framework has so far helped understand consciousness more on a quantitative level, that is, the degree to which one is alert and aware of specific contents of experience, regardless of how they are spatially and timely related to each other. Arguably, such a bi-dimensional characterization of consciousness has not made much progress in addressing the qualitative side of experience. Hence form consciousness (middle figure), which, provided a sufficient level of consciousness, considers the spatiotemporal relations between the contents of consciousness as key tools to understand what they feel like (i.e., qualitative experience). In other words, the same contents of consciousnesse.g., the arms in three different positions at three different time pointsmay feel differently according to their spatiotemporal relations (middle and right figures). For instance, an altered spatiotemporal structure may make one's movements feel as externally-generated and thus reduce SoA (as indicated by the dotted arrows in the right figure).
quantitative contents of awareness are not altered perse (the body is still there, accessible to awareness in all its elements), dysfunctions may lie in how such contents are structured in subjective space and time. For instance, when moving one arm from one position to the other, delusional patients are fully alert and aware of all quantitative features of their arm (color, shape, dimension, etc.), and yet they feel no agency over it. According to TTC, this may be due to dysfunctions in the spatiotemporal relation between the contents of awareness (i.e., the arm in two different positions at two different time points) and not in the contents of awareness perse. By contrast, in conditions such as hemianopia, the spatiotemporal patterns of spontaneous brain activity are supposedly preserved and so is the subjective experience of space and time. Here, dysfunctions are restricted to quantitative features of the content of awareness, e.g., how much of the visual field one can perceive (see Fig. 5).
In sum, PDs can be seen as primary disorders of space and time. As such, they may benefit from considering spatiotemporal alterations in spontaneous brain activity in their pathophysiology, while disorders of quantitative awareness (e.g., coma and hemianopia) may still rely on explanatory mechanisms targeting metabolic alterations and/or localized brain lesions (see Fig. 5).
The above can be extended to other psychiatric conditions such as bipolar disorder. An interesting work by Northoff and colleagues (2018) entitled "Too Fast or Too Slow? Time and Neuronal Variability in Bipolar Disorder" shows how time as measured in the resting-state brain can be related to time as subjectively experienced, both in mania and depression. Using the amplitude of neural activity as a measure of time within the brainwhere high neural variability indicates faster time processing and low variability slower time processingthe authors show that regions involved in the processing of inner time exhibit low variability in depression but high in mania. Conversely, regions processing outer time show high variability in depression but low in mania. These results notably cohere with the subjective experience of time in bipolar disorders. During mania, inner time is indeed fast and the environment goes "too slow", with people around patients having difficulty keeping up with them. Conversely, during depression inner time is slow and the environment goes "too fast", with patients reporting difficulty following conversations and keeping up with life's pace. Again, alterations here are not in the contents of experience perse, but in how they are timely linked to each other (form of consciousness).

Future directions and concluding remarks
The idea of a form of consciousness as featured by spatiotemporal dynamics in the resting-state brain may guide future research in multiple directions. First, following the proposal for a Spatiotemporal Psychopathology (Northoff and Duncun, 2016;Northoff, 2022), future studies could probe the extent to which spontaneous brain activityspecifically its spatiotemporal structurecan explain cognitive and emotional symptoms of PDs. TTC posits that symptoms such as working memory/attentional deficits and emotional dysregulation arise as a result of primary spatiotemporal alterations in spontaneous brain activity. Empirically testing these hypotheses might help understand whether TTC's proposals hold for other psychiatric conditions as well as larger samples. Second, future research may want to develop more sophisticated empirical measures to operationalize space and time as subjectively experienced, thereby allowing for a more precise link with the already-good indices that measures space and time within the brain (see 2.6, 2.7). Third, form of consciousness may also help better conceptualize how psychedelic compounds can induce prominent changes in qualitative experience (see Box 1), which have also shown remarkable results in ameliorating psychiatric symptoms (see da Costa et al., 2022 for an overview). Lastly, future studies could probe the effect of neuromodulation techniques such as transcranial direct current stimulation (tDCS) on brain topographies and timescales, and see whether a relatable effect takes place at the experiential level too. To the left are disorders of quantitative experience targeting the level and/or the content of consciousness, such as coma and hemianopia, respectively. What is dysfunctional here is the extent to which one is alert and/or able to experience environmental/bodily inputs. Metabolic alterations and localized brain lesions may suffice to explain such conditions (Shulman et al., 2003;de Graaf et al., 2012;Aru et al., 2012). PDs, on the other hand (right side), entail dysfunctions pertaining more to the qualitative side of experience. Research on localized brain alterations in PDs has not provided convincing results for specific biomarkers so far (Thibaut, 2018;Glannon, 2022). Together, this suggests that PDs may benefit from the broader framework of resting-state brain activity with its spatiotemporal features (i.e., form of consciousness).
In conclusion, this work makes the case that "disorder of consciousness" can be seen as an overarching condition subsuming not only quantitative dysfunctions in conscious experience, but also qualitative ones. Considering empirical evidence, methodological tools, and theoretical assumptions, the proposed idea of a form of consciousness may help better address qualitative experience, potentially opening a dialogue of mutual enrichment between consciousness research and psychiatry, which so far has mostly been neglected.

Declaration of Competing Interest
No declarations of interest.

Appendix 1
Overview of the literature that has been used when linking theories of consciousness to (1) psychiatric disorders and to (2) distorted sense of agency in schizophrenia (2). The following databases have been searched: PubMed, PsycInfo, Google Scholar* . 1) Theories of consciousness and psychiatric disorders (literature overview) Table 1 Theory: Higher Order Theory (HOT)

Papers:
• Taschereau Psychedelics are psychoactive compounds that can induce profound changes in subjective experience by exerting an agonist role on the 5-HT2AR serotoninergic receptor (Carhart-Harris, 2018). Interestingly, these states seem to relate to spatiotemporal alterations in the brain's resting-state, including decreased DMN-CEN anticorrelation (Carhart-Harris and Friston, 2019). If viewed through the TTC framework, such (spatial) neural alterations may account for people's (spatial) feelings of connectedness with the environment and dissolution of their ego-boundaries (Nour et al., 2016;Millière, 2017). In other words, psychedelics seem to directly alter the form of consciousness, yielding spatial changes both in spontaneous brain activity and subjective experience.
What is more, temporality seems also affected. Psychedelics appear to induce temporal large-scale variations in the resting-state and to alter time experience (Preller et al., 2018). For instance, they have been shown to dramatically reduce low-frequency and high-level brain rhythms such as α and β, which directly relates to the intensity of the subjective experience Muthukumaraswamy and Liley, 2018). (2019) have tried to interpret such neuronal and experiential alterations by putting forward the relaxed beliefs under psychedelics (REBUS) model. Accordingly, psychedelics would "relax" the strength of prior beliefs by increasing entropy levels within the resting-state brain. Relaxed prior beliefs, in turn, would result into stronger prediction errors, thereby allowing for priors update by incorporating new experiential perspectives (Haijen et al., 2018;Lyons and Carhart-Harris, 2018b).

Charart-Harris and Friston
Such a predictive-coding account of psychedelics does not contradict TTC and the idea of a form of consciousness. In fact, they may complement each other. As explained above (see 2.7), TTC does not reject predictive accounts of conscious experience. However, it places them in the broader framework of the spatiotemporal features of spontaneous brain activity. Accordingly, the relaxation of prior beliefs as postulated by the REBUS model may take place in virtue of a topographical reorganization of spontaneous brain activity, as also proposed in a recent work by Northoff et al. (2023).
A last important point to make regards the where of psychedelics' impact in the brain. This latter appears more prominent in higher-order associative regions as compared to lower-order sensory regions (Carhart-Harris and Friston, 2019;Pink-Hashkes et al., 2017). Accordingly, psychedelics would orchestrate larger-scale changes in spontaneous brain activity (form of consciousness), rather than more localized ones. This results into effects that are not confined to quantitative features of awareness (e.g., visual perception), as they extend to more dynamic qualitative alterations. Hallucinations are a case in point.
While one may argue that hallucinations under psychedelics represent simple quantitative changes in conscious experience, they seem to depend more on one's self-narrative rather than on actual external inputs. Those hallucinations are indeed thought to arise from signals traveling from higher-order cortices to, e.g., V5, rather than from localized changes in early sensory cortices, e.g., V1 (Carhart-Harris and Friston, 2019). As such, they cannot be fully explained by quantitative perceptual changes. Conversely, alterations in visual awareness as present in hemianopia are well-accounted for by deficits in lower-level visual pathways (Zeki and Leff, 2021). While in both cases perceptual alterations take place, those under psychedelics seem not restricted to sheer perception, as they relate toand depend onthe overall emotional self (Carhart-Harris and Friston, 2019) (similar conclusions may apply to hallucinations in schizophrenia).

Keywords:
• "Temporospatial theory" OR "spontaneous brain activity" OR "temporospatial mechanisms" OR "rest-to-task interaction" AND • "psychiatric disorders" OR "psychiatry" OR "psychopathology" OR "mental illness" Papers: 2) Theories of consciousness and distorted sense of agency in schizophrenia (literature overview) Table 2 Theory: Higher Order Theory (HOT)

Keywords:
• "Global Neuronal Workspace theory" OR "information broadcasting" OR "ignition" OR "implicitexplicit processing" AND • "schizophrenia/psychosis" OR "sense of agency" OR "distorted sense of agency schizophrenia/ psychosis" OR "delusions of alien control"   Predictive Processing Theory (PPT)

Keywords:
• "Integrated Information Theory" OR "information integration" AND • "schizophrenia/psychosis" OR "sense of agency" OR "distorted sense of agency schizophrenia/ psychosis" OR "delusions of alien control" Papers: • Keywords: • "Temporospatial theory" OR "spontaneous brain activity" OR "temporospatial mechanisms" OR "rest-to-task interaction AND • "schizophrenia/psychosis" OR "sense of agency" OR "distorted sense of agency schizophrenia/ psychosis" OR "delusions of alien control"