Altered sense of agency in schizophrenia and the putative psychotic prodrome

Meaningfulness and attachment: what dreams, psychosis and psychedelic states tell us about our need for connection

The human need to find meaning in life and the human need for connection may be two sides of the same coin, a coin forged in the developmental crucible of attachment. Our need for meaningfulness can be traced to our developmental need for connection in the attachment relationship. The free energy principle dictates that in order to resist a natural tendency towards disorder self-organizing systems must generate models that predict the hidden causes of phenomenal experience. In other words, they must make sense of things. In both an evolutionary and ontogenetic sense, the narrative self develops as a model that makes sense of experience. However, the self-model skews the interpretation of experience towards that which is predictable, or already "known." One may say it causes us to "take things personally." Meaning is felt more acutely when defenses are compromised, when the narrative self is offline. This enables meaning-making that is less egocentrically motivated. Dreams, psychosis, and psychedelic states offer glimpses of how we make sense of things absent a coherent narrative self. This has implications for the way we understand such states, and lays bare the powerful reach of attachment in shaping what we experience as meaningful.

Abnormalities in motor adaptation to different types of perturbations in schizophreniaperturbations in schizophrenia

Schizophrenia is a mental health disorder that often includes psychomotor disturbances, impacting how individuals adjust their motor output based on the cause of motor errors. While previous motor adaptation studies on individuals with schizophrenia have largely focused on large and consistent perturbations induced by abrupt experimental manipulations, such as donning prism goggles, the adaptation process to random perturbations, either caused by intrinsic motor noise or external disturbances, has not been examined - despite its ecological relevance. Here, we used a unified behavioral task paradigm to examine motor adaptation to perturbations of three causal structures among individuals in the remission stage of schizophrenia, youth with ultra-high risk of psychosis, adults with active symptoms, and age-matched controls. Results showed that individuals with schizophrenia had reduced trial-by-trial adaptation and large error variance when adapting to their own motor noise. When adapting to random but salient perturbations, they showed intact adaptation and normal causal inference of errors. This contrasted with reduced adaptation to large yet consistent perturbations, which could reflect difficulties in forming cognitive strategies rather than the often-assumed impairments in procedural learning or sense of agency. Furthermore, the observed adaptation effects were correlated with the severity of positive symptoms across the diagnosis groups. Our findings suggest that individuals with schizophrenia face challenges in accommodating intrinsic perturbations when motor errors are ambiguous but adapt with intact causal attribution when errors are salient.

Body image as a mediator in the relationship between psychotic experiences and later disordered eating: A 12-month longitudinal study in high school adolescents

BACKGROUND

The relationship between psychosis and disordered eating remains a challenging area of research to which little interest was paid. Using longitudinal data, we aimed to explore the hypothesis that the pathways from psychotic experiences (PEs) to disordered eating (DE) and body-mass index (BMI) are mediated by body-image disturbances.

METHODS

A prospective longitudinal study was performed. High-school students (N = 510, 61.2% females, mean age of 16.05 ± 1.01 years) were asked to complete three scheduled assessments (Baseline, 6 months, and 12 months).

RESULTS

Two body image components, that is, Overweight Preoccupation and Body Area Satisfaction, mediated the prospective association between baseline PEs and DE 12 months later. Direct effects were significant. After accounting for indirect effects through more severe body image concerns at 6 months, higher baseline PEs were significantly associated with greater DE at 12 months. Baseline PEs and 6-month body image explained a significant proportion of variance in 12-month DE. However, we did not find evidence of a direct prospective association between PEs and BMI.

CONCLUSION

This study is the first to assess the mediating role of body image between PEs and DE. Findings offer promising new avenues for early intervention to help mitigate the effects of PEs on DE in adolescents.

Probing corporeal awareness in women through virtual reality induction of embreathment illusion

We capitalized on the respiratory bodily illusion that we discovered in a previous study and called 'Embreathment' where we showed that breathing modulates corporeal awareness in men. Despite the relevance of the issue, no such studies are available in women. To bridge this gap, we tested whether the synchronization of avatar-participant respiration patterns influenced females' bodily awareness. We collected cardiac and respiratory interoceptive measures, administered body (dis)satisfaction questionnaires, and tracked participants' menstrual cycles via a mobile app. Our approach allowed us to characterize the 'Embreathment' illusion in women, and explore the relationships between menstrual cycle, interoception and body image. We found that breathing was as crucial as visual appearance in eliciting feelings of ownership and held greater significance than any other cue with respect to body agency in both women and men. Moreover, a positive correlation between menstrual cycle days and body image concerns, and a negative correlation between interoceptive sensibility and body dissatisfaction were found, confirming that women's body dissatisfaction arises during the last days of menstrual cycle and is associated with interoception. These findings have potential implications for corporeal awareness alterations in clinical conditions like eating disorders and schizophrenia.

Agency in schizophrenia and autism: a systematic review

Introduction

Previous research suggests that altered experiences of agency are an underlying vulnerability in both schizophrenia and autism. Here, we explore agency as a potential transdiagnostic factor by conducting a systematic review of existing literature investigating agency in autism and schizophrenia individually and together.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted three systematic searches on PsycINFO, Embase, Medline, PubMed and Web of Science to identify studies that investigated (1) agency in schizophrenia, (2) agency in autism, and (3) agency in both schizophrenia and autism.

Results

A total of 31 articles met eligibility criteria for inclusion and data extraction, with 24 measuring agency in schizophrenia, 7 investigating agency in autism, and no articles comparing the two. Results show that, compared to control populations, agency is significantly different in every identified schizophrenia study and generally not significantly different in autism.

Discussion

Importantly, we identified a lack of studies using common tasks and a disproportionate number of studies investigating different dimensions of agency across the two conditions, resulting in limited grounds for valid comparison.

Systematic review registration

Prospero, CRD42021273373.

The bodily self from psychosis to psychedelics

The sense of self is a foundational element of neurotypical human consciousness. We normally experience the world as embodied agents, with the unified sensation of our selfhood being nested in our body. Critically, the sense of self can be altered in psychiatric conditions such as psychosis and altered states of consciousness induced by psychedelic compounds. The similarity of phenomenological effects across psychosis and psychedelic experiences has given rise to the "psychotomimetic" theory suggesting that psychedelics simulate psychosis-like states. Moreover, psychedelic-induced changes in the sense of self have been related to reported improvements in mental health. Here we investigated the bodily self in psychedelic, psychiatric, and control populations. Using the Moving Rubber Hand Illusion, we tested (N = 75) patients with psychosis, participants with a history of substantial psychedelic experiences, and control participants to see how psychedelic and psychiatric experience impacts the bodily self. Results revealed that psychosis patients had reduced Body Ownership and Sense of Agency during volitional action. The psychedelic group reported subjective long-lasting changes to the sense of self, but no differences between control and psychedelic participants were found. Our results suggest that while psychedelics induce both acute and enduring subjective changes in the sense of self, these are not manifested at the level of the bodily self. Furthermore, our data show that bodily self-processing, related to volitional action, is disrupted in psychosis patients. We discuss these findings in relation to anomalous self-processing across psychedelic and psychotic experiences.

Abnormal sense of agency in eating disorders

The feeling of controlling one's own actions and, through them, impacting the external environment (i.e. Sense of Agency-SoA) can be relevant in the eating disorders (EDs) symptomatology. Yet, it has been poorly investigated. This study aims to implicitly assess SoA exploiting the Sensory Attenuation paradigm in two groups of EDs patients (Anorexia Nervosa Restrictive and Anorexia Nervosa Binge-Purging or Bulimia Nervosa) compared to a control group. We find that controls perceive self-generated stimuli as less intense than other-generated ones showing the classic pattern of sensory attenuation. By contrast, EDs patients show the opposite pattern, with self-generated perceived as more intense than other-generated stimuli. This result indicates an alteration of the implicit component of the feeling of control in EDs patients, thus suggesting a potential implication of these results for the clinical practice and the treatment of EDs symptomatology.

Impaired perception of temporal contiguity between action and effect is associated with disorders of agency in schizophrenia

Delusions of control in schizophrenia are characterized by the striking feeling that one's actions are controlled by external forces. We here tested qualitative predictions inspired by Bayesian causal inference models, which suggest that such misattributions of agency should lead to decreased intentional binding. Intentional binding refers to the phenomenon that subjects perceive a compression of time between their intentional actions and consequent sensory events. We demonstrate that patients with delusions of control perceived less self-agency in our intentional binding task. This effect was accompanied by significant reductions of intentional binding as compared to healthy controls and patients without delusions. Furthermore, the strength of delusions of control tightly correlated with decreases in intentional binding. Our study validated a critical prediction of Bayesian accounts of intentional binding, namely that a pathological reduction of the prior likelihood of a causal relation between one's actions and consequent sensory events-here captured by delusions of control-should lead to lesser intentional binding. Moreover, our study highlights the import of an intact perception of temporal contiguity between actions and their effects for the sense of agency.

Perceptual training modifies temporal sensitivity and a sense of agency

Perceptual training has been argued to be a potential means to modify temporal sensitivity (the ability to detect a time-based discrepancy between two stimuli) with previous studies providing preliminary evidence that perceptual training can lead to increased temporal sensitivity. However, previous studies have not employed a control group and therefore cannot rule out the possibility that the observed effects are due to repeated completion of the task, rather than the training itself. Moreover, despite temporal sensitivity being suggested to be an important aspect of the sense of agency, the effects of perceptual training on the sense of agency have not been explored. Therefore, this study aimed to explore the effects of perceptual training on the sense of agency and replicate previously observed effects on temporal sensitivity while utilizing a more rigorous methodology. Given the existing literature, it was predicted that the sense of agency and temporal sensitivity will be enhanced following perceptual training. Temporal sensitivity was only weakly modified by perceptual training when compared to the control condition. Sense of agency was significantly modulated by perceptual training, over and above the control condition. This study's findings present novel evidence indicating that perceptual training can influence high-level processes such as the sense of agency and temporal sensitivity.

Impaired sense of agency and associated confidence in psychosis

The Sense of Agency (SoA), our sensation of control over our actions, is a fundamental mechanism for delineating the Self from the environment and others. SoA arises from implicit processing of sensorimotor signals as well as explicit higher-level judgments. Psychosis patients suffer from difficulties in the sense of control over their actions and accurate demarcation of the Self. Moreover, it is unclear if they have metacognitive insight into their aberrant abilities. In this pre-registered study, we examined SoA and its associated confidence judgments using an embodied virtual reality paradigm in psychosis patients and controls. Our results show that psychosis patients not only have a severely reduced ability for discriminating their actions but they also do not show proper metacognitive insight into this deficit. Furthermore, an exploratory analysis revealed that the SoA capacities allow for high levels of accuracy in clinical classification of psychosis. These results indicate that SoA and its metacognition are core aspects of the psychotic state and provide possible venues for understanding the underlying mechanisms of psychosis, that may be leveraged for novel clinical purposes.

Co-occurring psychotic and eating disorders in England: findings from the 2014 Adult Psychiatric Morbidity Survey

BACKGROUND

Psychotic disorders and eating disorders are complex mental illnesses associated with increased mortality and functional impairment. This study aimed to investigate the co-occurrence and relationships between eating disorders and psychotic disorders and assess the mediation effect of mood instability.

METHODS

This study used data from the Adult Psychiatric Morbidity Survey (APMS) 2014, a general population-based survey in England. Participants (total N = 7546, female N = 4488, male N = 3058, mean age = 52.3 years) were categorised based on psychotic disorder status into the groups of probable psychosis, diagnosed psychosis, and healthy controls without psychosis. The dependent variable of this study was the presence or absence of an eating disorder, with mood instability as the mediator. Logistic regression and mediation analyses were conducted to assess the relationships between these variables.

RESULTS

Both probable and diagnosed psychoses were significantly related to the presence of an eating disorder, and mood instability was found to be a mediating variable with moderate effect.

CONCLUSION

The present study demonstrates a significant relationship between eating disorders and psychotic disorders in the English general population, indicating higher levels of co-occurrence between these two groups of disorders than when compared with healthy controls. The findings also suggest the relationship between eating and psychotic disorders is mediated, to an extent, by the presence of mood instability traits. Future research could extend the present study's findings through assessing whether specific eating disorders are more significantly related to psychotic disorders than others.

Depressive traits are associated with a reduced effect of choice on intentional binding

A sense of agency (SoA) over wilful actions is thought to be dependent on the level of choice and the nature of the outcome. In a preregistered study, we manipulated choice and valence of outcome to assess the relationship between SoA across the depression and psychosis continuum. Participants (N = 151) completed a Libet Clock task, in which they had either a free or forced choice to press one of two buttons and received either a rewarding or punishing outcome. Participants also completed questionnaires on depressive and psychosis-like traits. Rewarding outcomes increased intentional binding. The evidence favoured no effect of choice on average, but this was influenced by inter-individual differences. Individuals reporting more depressive traits had less of a difference in intentional binding between free and forced choice conditions. We show that implicit SoA is sensitive to outcome valence and the effect of choice differs across the depression continuum.

Agency Deficits in a Human Genetic Model of Schizophrenia: Insights From 22q11DS Patients

Schizophrenia is a chronic and disabling mental illness characterized by a disordered sense of self. Current theories suggest that deficiencies in the sense of control over one's actions (Sense of Agency, SoA) may underlie some of the symptoms of schizophrenia. However, it is not clear if agency deficits are a precursor or a result of psychosis. Here, we investigated full body agency using virtual reality in a cohort of 22q11 deletion syndrome participants with a genetic propensity for schizophrenia. In two experiments employing virtual reality, full body motion tracking, and online feedback, we investigated SoA in two separate domains. Our results show that participants with 22q11DS had a considerable deficit in monitoring their actions, compared to age-matched controls in both the temporal and spatial domain. This was coupled with a bias toward erroneous attribution of actions to the self. These results indicate that nonpsychotic 22q11DS participants have a domain general deficit in the conscious sensorimotor mechanisms underlying the bodily self. Our data reveal an abnormality in the SoA in a cohort with a genetic predisposition for schizophrenia, but without psychosis, providing evidence that deficits in delineation of the self may be a precursor rather than a result of the psychotic state.

The Role of the Medial Prefontal Cortex in Self-Agency in Schizophrenia

Schizophrenia is a disorder of the self. In particular, patients show cardinal deficits in self-agency (i.e., the experience and awareness of being the agent of one’s own thoughts and actions) that directly contribute to positive psychotic symptoms of hallucinations and delusions and distort reality monitoring (defined as distinguishing self-generated information from externally-derived information). Predictive coding models suggest that the experience of self-agency results from a minimal prediction error between the predicted sensory consequence of a self-generated action and the actual outcome. In other words, the experience of self-agency is thought to be driven by making reliable predictions about the expected outcomes of one’s own actions. Most of the agency literature has focused on the motor system; here we present a novel viewpoint that examines agency from a different lens using distinct tasks of reality monitoring and speech monitoring. The self-prediction mechanism that leads to self-agency is necessary for reality monitoring in that self-predictions represent a critical precursor for the successful encoding and memory retrieval of one’s own thoughts and actions during reality monitoring to enable accurate self-agency judgments (i.e., accurate identification of self-generated information). This self-prediction mechanism is also critical for speech monitoring where we continually compare auditory feedback (i.e., what we hear ourselves say) with what we expect to hear. Prior research has shown that the medial prefrontal cortex (mPFC) may represent one potential neural substrate of this self-prediction mechanism. Unfortunately, patients with schizophrenia (SZ) show mPFC hypoactivity associated with self-agency impairments on reality and speech monitoring tasks, as well as aberrant mPFC functional connectivity during intrinsic measures of agency during resting states that predicted worsening psychotic symptoms. Causal neurostimulation and neurofeedback techniques can move the frontiers of schizophrenia research into a new era where we implement techniques to manipulate excitability in key neural regions, such as the mPFC, to modulate patients’ reliance on self-prediction mechanisms on distinct tasks of reality and speech monitoring. We hypothesize these findings will show that mPFC provides a unitary basis for self-agency, driven by reliance on self-prediction mechanisms, which will facilitate the development of new targeted treatments in patients with schizophrenia.

Disrupted Sense of Agency as a State Marker of First-Episode Schizophrenia: A Large-Scale Follow-Up Study

Background: Schizophrenia is often characterized by a general disruption of self-processing and self-demarcation. Previous studies have shown that self-monitoring and sense of agency (SoA, i.e., the ability to recognize one's own actions correctly) are altered in schizophrenia patients. However, research findings are inconclusive in regards to how SoA alterations are linked to clinical symptoms and their severity, or cognitive factors. Methods: In a longitudinal study, we examined 161 first-episode schizophrenia patients and 154 controls with a continuous-report SoA task and a control task testing general cognitive/sensorimotor processes. Clinical symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Results: In comparison to controls, patients performed worse in terms of recognition of self-produced movements even when controlling for confounding factors. Patients' SoA score correlated with the severity of PANSS-derived "Disorganized" symptoms and with a priori defined symptoms related to self-disturbances. In the follow-up, the changes in the two subscales were significantly associated with the change in SoA performance. Conclusion: We corroborated previous findings of altered SoA already in the early stage of schizophrenia. Decreased ability to recognize self-produced actions was associated with the severity of symptoms in two complementary domains: self-disturbances and disorganization. While the involvement of the former might indicate impairment in self-monitoring, the latter suggests the role of higher cognitive processes such as information updating or cognitive flexibility. The SoA alterations in schizophrenia are associated, at least partially, with the intensity of respective symptoms in a state-dependent manner.

Confusion within feedback control between cognitive and sensorimotor agency cues in self-other attribution

Self-other sensory attribution is necessary to realize feedback control because the self-attribution of sensations can drive feedback control. Some studies have suggested that self-other attribution is realized by the integration of both sensorimotor cues, including internal prediction and/or sensory feedback, and cognitive cues, such as knowledge or thought. However, in motor control, it remains unclear whether and how cognitive cues affect self-other attribution. In a feedback-control task, this study manipulated the movements (sensorimotor cue) and appearances (cognitive cue) of the cursor provided as visual feedback on participants' sinusoidal movement. Participants were required to make a self-other attribution regarding whether the cursor's movement reflected their actual movement without being confused by the cursor's appearance. Experiments 1 and 2 showed that participants made illusory self-other attributions within feedback control based on cursor appearance only when the information on cursor movement was reduced by causing the cursor to flicker at 8 Hz. However, in Experiment 3, in which the cursor flickering at 4 Hz reduced the information on cursor movement to a level too low for conscious self-other attribution, cursor appearance was not utilized. Our findings suggest that the effects of cognitive cues on self-other attribution are determined by the cue integration strategy selected for the given situation.

Embodied Predictions, Agency, and Psychosis

Psychotic symptoms, i.e., hallucinations and delusions, involve gross departures from conscious apprehension of consensual reality; respectively, perceiving and believing things that, according to same culture peers, do not obtain. In schizophrenia, those experiences are often related to abnormal sense of control over one's own actions, often expressed as a distorted sense of agency (i.e., passivity symptoms). Cognitive and computational neuroscience have furnished an account of these experiences and beliefs in terms of the brain's generative model of the world, which underwrites inferences to the best explanation of current and future states, in order to behave adaptively. Inference then involves a reliability-based trade off of predictions and prediction errors, and psychotic symptoms may arise as departures from this inference process, either an over- or under-weighting of priors relative to prediction errors. Surprisingly, there is empirical evidence in favor of both positions. Relatedly, there is evidence for both an enhanced and a diminished sense of agency in schizophrenia. How can this be? We argue that there is more than one generative model in the brain, and that ego- and allo-centric models operate in tandem. In brief, ego-centric models implement corollary discharge signals that cancel out the effects of self-generated actions while allo-centric models compare several hypothesis regarding the causes of sensory inputs (including the self among the potential causes). The two parallel hierarchies give rise to different levels of agency, with ego-centric models subserving "feelings of agency" and allo-centric predictions giving rise to "judgements of agency." Those two components are weighted according to their reliability and combined, generating a higher-level "sense of agency." We suggest that in schizophrenia a failure of corollary discharges to suppress self-generated inputs results in the absence of a "feeling of agency" and in a compensatory enhancement of allo-centric priors, which might underlie hallucinations, delusions of control but also, under certain circumstances, the enhancement of "judgments of agency." We discuss the consequences of such a model, and potential courses of action that could lead to its falsification.

Agency judgments in post-stroke patients with sensorimotor deficits

Sense of agency refers to the feeling of being in control of one's actions. Previous research has demonstrated that sense of agency is produced through the sensorimotor system, which is involved in comparing internal predictions with sensory feedback in motor control. Therefore, sensorimotor deficits might impair agency through a sensorimotor system malfunction. The present study examined this hypothesis by investigating post-stroke patients who had suffered a subcortical stroke that damaged regions associated with sensorimotor function. To examine agency judgments with respect to motor control, we adopted a self-other attribution task and applied it to post-stroke patients. Participants traced a horizontal straight line and received visual feedback through a cursor on a monitor. The cursor movement reflected either the participants' actual movement or the movement of an "other" that had been previously recorded. Participants judged whether the cursor movement reflected their own movement (self) or an other's movement while they engaged in four cycles of the horizontal tracing movement. After each trial, participants reported their self-other judgment on a nine-point scale. Post-stroke patients completed the experiment with their paretic as well as their non-paralyzed upper limbs. Compared to healthy controls, patients made significantly more self-attributions of others' movements. Interestingly, such misattributions were observed in the patients' performance using both paretic and non-paralyzed upper limbs. These results suggest that post-stroke patients with sensorimotor deficits form misattributions that cannot be explained solely by the sensorimotor system's role in motor control. We discuss these misattributions in post-stroke patients in terms of cue integration theory.

The evolving sense of agency: Context recency and quality modulate the interaction between prospective and retrospective processes

Humans acquire a sense of agency through their interactions with the world and their sensory consequences. Previous studies have highlighted stable agency-related phenomena like intentional binding, which depend on both prospective, context-dependent and retrospective, outcome-dependent processes. In the current study, we investigated the interaction between prospective and retrospective processes underlying the adaptation of an ongoing sense of agency. The results showed that prospective intentional binding developed during a temporal window of up to 20 prior events was independent of the nature of the ongoing event. By contrast, the characteristics of the ongoing event retrospectively influenced prospective intentional binding developed during a temporal window narrower than 6 prior events. These findings characterize the interaction between prospective and retrospective mechanisms as a fundamental process to continuously update the sense of agency through sensorimotor learning. High psychosis-like experience traits weakened this interaction, suggesting that reduced adaption to the context contributes to altered self-experience.

Connecting action control and agency: Does action-effect binding affect temporal binding?

The sense of agency, i.e., the notion that we, as agents, are in control of our own actions and can affect our environment by acting, is an integral part of human volition. Recent work has attempted to ground agency in basic mechanisms of human action control. Along these lines, action-effect binding has been shown to affect explicit judgments of agency. Here, we investigate if such action-effect bindings are also related to temporal binding which is often used as an implicit measure of agency. In two experiments, we found evidence for the establishment of short-term action-effect bindings as well as temporal binding effects. However, the two phenomena were not associated with each other. This finding suggests that the relation of action control and agency is not a simple one, and it adds to the evidence in favor of a dissociation between subjective agency and perceptual biases such as temporal binding.

Environmental control and psychosis-relevant traits modulate the prospective sense of agency in non-clinical individuals

The sense of agency concerns the experience of being the source of one's own actions and their consequences. An altered sense of agency can occur due to task automation and in psychosis. We tested in a non-clinical sample the hypothesis that reducing voluntary task control diminishes intentional binding as an implicit indicator of the sense of agency, possibly interacting with psychosis-relevant personality traits. Agent-device interactions were manipulated obtaining positive-control (voluntary interaction), no-control (automation), and negative-control (device-commanded interaction) groups. The main results showed reduced prospective intentional binding (predictive coding of action consequences) in the no-control and negative-control groups, compared to the positive-control group. Psychosis-like experiences covaried positively with intentional binding in the no-control group, but negatively in the negative-control group. Moreover, positive-social traits were associated with increased intentional binding in the positive-control group. These findings demonstrate the interplay between environmental and individual differences variables in establishing the implicit sense of agency.

Associations among domains of self-disturbance in schizophrenia

Self-disturbances are increasingly recognized as important, possibly even central, features of schizophrenia. However, little is known about the associations among different manifestations of self-disturbances. The aims of the current study were threefold. We aimed to (1) replicate previous findings of increased self-disturbances in schizophrenia, (2) correlate manifestations of self-disturbances in schizophrenia across three domains, and (3) correlate self-disturbances with five symptoms domains of schizophrenia, including positive, negative, disorganized symptoms, excitement, and emotional distress. We examined three domains of self-experience, including somatosensation, anomalous self-experiences, and self-concept clarity. Participants included 48 individuals with schizophrenia and 36 non-psychiatric controls. The results of this study replicate previous findings of significantly higher levels of self-disturbances in people with schizophrenia. The results also indicate positive correlations between the domains of anomalous self-experiences and self-concept clarity, but not somatosensation, in individuals with schizophrenia. As well, anomalous self-experiences were positively correlated with positive symptoms, disorganized symptoms, and emotional distress and self-concept clarity was negatively correlated with disorganized symptoms and emotional distress.

Delusions of control in schizophrenia: Resistant to the mind's best trick?

The existence of a free will is fiercely debated in neuroscience and philosophy. The debate has great impact on society and our self-understanding as human beings. Behavioral and electrophysiological data have challenged the intuitive assumption that human behavior is the result of conscious intentions. This notion has important implications for delusions of control in schizophrenia, where patients experience bodily movements as not being controlled by themselves. Current theories explain control delusions as a deficit to perceive certain aspects of motor control, but many findings are inconsistent with this idea. Here, an alternative view is proposed: Control delusions might be triggered by an even more veridical perception of the temporal order of intentions and actions. This hypothesis is supported by evidence that (a) conscious intentions in healthy subjects are often based on retrospective inferences, (b) temporal recalibrations of conscious percepts occur in healthy subjects and are disturbed in schizophrenia and (c) basic perceptual functions of schizophrenic patients are less influenced by expectations and therefore they can sometimes be closer to physical reality than those of healthy subjects.

Social cognition and self-other distinctions in neuropsychiatry: Insights from schizophrenia and Tourette syndrome

Impairments in social cognition may reflect dysfunction of disorder specific or disorder general mechanisms. Although cross-disorder comparison may prove insightful, few studies have compared social cognition in different neuropsychiatric disorders. Parallel investigation of schizophrenia and Tourette syndrome (TS) is encouraged by similarities including the presence of problematic social behavior, echophenomena, emotional dysregulation and dopamine dysfunction. Focusing on tests of social cognition administered in both disorders, this review aims to summarize behavioral, neurophysiological and neuroimaging findings, before exploring how these may contribute to clinical symptoms. Studies investigating social cognition (imitation, emotion recognition, and understanding of beliefs or intentions) in patients with schizophrenia or TS were identified through Web of Science and PubMed searches. Although findings indicate that social cognitive deficits are more apparent in schizophrenia, adults with TS can exhibit similar task performance to patients with paranoia. In both disorders, behavioral and neuroimaging findings raise the possibility of increased internal simulation of others' actions and emotions, in combination with a relative under-application of mentalizing. More specifically, dysfunction in neurobiological substrates such as temporo-parietal junction and inferior frontal gyrus may underlie problems with self-other distinctions in both schizophrenia and TS. Difficulties in distinguishing between actions and mental states linked to the self and other may contribute to a range of psychiatric symptoms, including emotional dysregulation, paranoia, social anhedonia and socially disruptive urges. Comparing different patient populations could therefore reveal common neuro-cognitive risk factors for the development of problematic social behaviors, in addition to markers of resilience, coping strategies and potential neuro-compensation mechanisms.

A Delusion of Control - What happens to a sense of Agency in Schizophrenic patients?

The sense of agency is known to be disrupted in Schizophrenia. This article explores the transition from the comparator model to the two-step model of agency, in order to review the paper ‘In and out of control: brain mechanisms linking fluency of action selection to self-agency in patients with Schizophrenia’1. A sense of agency involves using retrospective cues to make causal inferences, but this paper also introduces a new, prospective aspect. This paper shows that subliminal priming, a prospective cue, increases the reported sense of agency over a subsequent action outcome. It also shows that in schizophrenic patients, retrospective cues had more of an influence on their reported sense of agency, while conversely, prospective cues had less influence. This may reflect a greater reliance on retrospective cues in schizophrenia, which could be one of the underlying factors for some of the delusions seen in schizophrenia. Using fMRI measurements during the task, results suggest that angular gyrus activation reflects the experience of non-agency. In healthy controls, they saw altered connectivity between frontal areas and the angular gyrus associated with priming. In schizophrenic patients, there was no effect of priming on activation of the angular gyrus, or frontoparietal connectivity. In our review, we have introduced a putative schema that suggests that the action selection signals from the frontal lobes into the angular gyrus represent the prospective aspect of agency. This connection is disrupted In schizophrenia, and that may be why prospective agency is impaired.

Know thy agency in predictive coding: Meta-monitoring over forward modeling

Though the computation of agency is thought to be based on prediction error, it is important for us to grasp our own reliability of that detected error. Here, the current study shows that we have a meta-monitoring ability over our own forward model, where the accuracy of motor prediction and therefore of the felt agency are implicitly evaluated. Healthy participants (N=105) conducted a simple motor control task and SELF or OTHER visual feedback was given. The relationship between the accuracy and confidence in a mismatch detection task and in a self-other attribution task was examined. The results suggest an accuracy-confidence correlation in both tasks, indicating our meta-monitoring ability over such decisions. Furthermore, a statistically identified group with low accuracy and low confidence was characterized as higher schizotypal people. Finally, what we can know about our own forward model and how we can know it is discussed.

Abnormal agency experiences in schizophrenia patients: Examining the role of psychotic symptoms and familial risk

Experiencing self-agency over one's own action outcomes is essential for social functioning. Recent research revealed that patients with schizophrenia do not use implicitly available information about their action-outcomes (i.e., prime-based agency inference) to arrive at self-agency experiences. Here, we examined whether this is related to symptoms and/or familial risk to develop the disease. Fifty-four patients, 54 controls, and 19 unaffected (and unrelated) siblings performed an agency inference task, in which experienced agency was measured over action-outcomes that matched or mismatched outcome-primes that were presented before action performance. The Positive and Negative Syndrome Scale (PANSS) and Comprehensive Assessment of Symptoms and History (CASH) were administered to assess psychopathology. Impairments in prime-based inferences did not differ between patients with symptoms of over- and underattribution. However, patients with agency underattribution symptoms reported significantly lower overall self-agency experiences. Siblings displayed stronger prime-based agency inferences than patients, but weaker prime-based inferences than healthy controls. However, these differences were not statistically significant. Findings suggest that impairments in prime-based agency inferences may be a trait characteristic of schizophrenia. Moreover, this study may stimulate further research on the familial basis and the clinical relevance of impairments in implicit agency inferences.

The self-attribution bias and paranormal beliefs

The present study investigated the relation between paranormal beliefs, illusory control and the self-attribution bias, i.e., the motivated tendency to attribute positive outcomes to oneself while negative outcomes are externalized. Visitors of a psychic fair played a card guessing game and indicated their perceived control over randomly selected cards as a function of the congruency and valence of the card. A stronger self-attribution bias was observed for paranormal believers compared to skeptics and this bias was specifically related to traditional religious beliefs and belief in superstition. No relation between paranormal beliefs and illusory control was found. Self-report measures indicated that paranormal beliefs were associated to being raised in a spiritual family and to anomalous experiences during childhood. Thereby this study suggests that paranormal beliefs are related to specific cognitive biases that in turn are shaped by socio-cultural factors.

Self is "other", other is "self": poor self-other discriminability explains schizotypal twisted agency judgment

Anomalous agency has been reported clinically and empirically for people with schizophrenia. This finding is expected to contribute to understanding positive symptomatology in schizophrenia in terms of a general neurocomputational model of motor control, because anomalous agency has also been reported in schizotypal traits in the general population. However, superficially opposite conclusions have been suggested: over-attributed or under-attributed agency in patients. In this work, healthy participants (N=104) were presented continuous morphed self-other visual feedback of their reaching movements and rated the agency they felt for it. The slope of the regression line in stimuli-response coordination as a function of self-other discriminability was estimated for each participant. The estimated slopes were significantly associated with positive schizotypal symptomatology. Higher schizotypal participants exhibited a lower slope, indicating poorer discriminability between their own and others' movements. Furthermore, the estimated regression lines in the high and low groups are predicted to cross at the approximately center point in the coordinates, which should produce both over-attribution and under-attribution errors for the high group compared with low group. The pattern of schizotypal attribution error depends on the S/N (signal-to-noise) ratio of the given stimuli within our sensorimotor system where the self-originated stimulus is the signal to be detected. The current study, for the first time, suggests both over- and under-attribution within participants scoring high on schizotypy.

Shall we really say goodbye to first rank symptoms?

BACKGROUND

First rank symptoms (FRS) of schizophrenia have been used for decades for diagnostic purposes. In the new version of the DSM-5, the American Psychiatric Association (APA) has abolished any further reference to FRS of schizophrenia and treats them like any other "criterion A" symptom (e.g. any kind of hallucination or delusion) with regard to their diagnostic implication. The ICD-10 is currently under revision and may follow suit. In this review, we discuss central points of criticism that are directed against the continuous use of first rank symptoms (FRS) to diagnose schizophrenia.

METHODS

We describe the specific circumstances in which Schneider articulated his approach to schizophrenia diagnosis and discuss the relevance of his approach today. Further, we discuss anthropological and phenomenological aspects of FRS and highlight the importance of self-disorder (as part of FRS) for the diagnosis of schizophrenia. Finally, we will conclude by suggesting that the theory and rationale behind the definition of FRS is still important for psychopathological as well as neurobiological approaches today.

RESULTS

Results of a pivotal meta-analysis and other studies show relatively poor sensitivity, yet relatively high specificity for FRS as diagnostic marker for schizophrenia. Several methodological issues impede a systematic assessment of the usefulness of FRS in the diagnosis of schizophrenia. However, there is good evidence that FRS may still be useful to differentiate schizophrenia from somatic causes of psychotic states. This may be particularly important in countries or situations with little access to other diagnostic tests. FRS may thus still represent a useful aid for clinicians in the diagnostic process.

CONCLUSION

In conclusion, we suggest to continue a tradition of careful clinical observation and fine-grained psychopathological assessment, including a focus on symptoms regarding self-disorders, which reflects a key aspect of psychosis. We suggest that the importance of FRS may indeed be scaled down to a degree that the occurrence of a single FRS alone should not suffice to diagnose schizophrenia, but, on the other hand, absence of FRS should be regarded as a warning sign that the diagnosis of schizophrenia or schizoaffective disorder is not warranted and requires specific care to rule out other causes, particularly neurological and other somatic disorders. With respect to the current stage of the development of ICD-11, we appreciate the fact that self-disorders are explicitly mentioned (and distinguished from delusions) in the list of mandatory symptoms but still feel that delusional perceptions and complex hallucinations as defined by Schneider should be distinguished from delusions or hallucinations of "any kind". Finally, we encourage future research to explore the psychopathological context and the neurobiological correlates of self-disorders as a potential phenotypic trait marker of schizophrenia.

Development of Embodied Sense of Self Scale (ESSS): Exploring Everyday Experiences Induced by Anomalous Self-Representation

The scientific exploration of the self has progressed, with much attention focused on the Embodied Sense of Self (ESS). Empirical studies have suggested the mechanisms for self-representation. On the other hand, less attention has been paid to the subjectivity itself of the self. With reference to previous studies, the current study collected items that reflect the ESS and statistically extracted three factors for it: Ownership, Agency, and Narrative. The developed questionnaire [Embodied Sense of Self Scale (ESSS)] showed good enough validity and reliability for practical use. Furthermore, ESSS discriminated schizophrenia, a disorder of the ESS, from controls. We discuss the factorial structure of ESS and the relationship among factors on the basis of the current results.

Neurobiological Models of Self-Disorders in Early Schizophrenia

Self-disorders (SDs) (from the German Ichstörungen) are alterations of the first-person perspective, long associated with schizophrenia, particularly in early phases. Although psychopathological features of SDs continue to be studied, their neurobiological underpinnings are unknown. This makes it difficult to integrate SDs into contemporary models of psychosis. The present review aims to address this issue, starting from an historical excursus revealing an interconnection between neuroscientific models and the origin of the psychopathological concept of SDs. Subsequently, the more recent neurobiological models related to SDs are discussed, particularly with respect to the onset of schizophrenia.

Individual differences in action co-representation: not personal distress or subclinical psychotic experiences but sex composition modulates joint action performance

Successful social interaction requires the ability to integrate as well as distinguish own and others’ actions. Normally, the integration and distinction of self and other are a well-balanced process, occurring without much effort or conscious attention. However, not everyone is blessed with the ability to balance self–other distinction and integration, resulting in personal distress in reaction to other people’s emotions or even a loss of self [e.g., in (subclinical) psychosis]. Previous research has demonstrated that the integration and distinction of others’ actions cause interference with one’s own action performance (commonly assessed with a social Simon task). The present study had two goals. First, as previous studies on the social Simon effect employed relatively small samples (N < 50 per test), we aimed for a sample size that allowed us to test the robustness of the action interference effect. Second, we tested to what extent action interference reflects individual differences in traits related to self–other distinction (i.e., personal distress in reaction to other people’s emotions and subclinical psychotic symptoms). Based on a questionnaire study among a large sample (N = 745), we selected a subsample (N = 130) of participants scoring low, average, or high on subclinical psychotic symptoms, or on personal distress. The selected participants performed a social Simon task. Results showed a robust social Simon effect, regardless of individual differences in personal distress or subclinical psychotic symptoms. However, exploratory analyses revealed that the sex composition of interaction pairs modulated social Simon effects. Possible explanations for these findings are discussed.

Ambiguity between self and other: Individual differences in action attribution

Individuals differ in their ability to attribute actions to self or other. This variance is thought to explain, in part, the experience of voice-hearing. Misattribution can also be context-driven. For example, causal ambiguity can arise when the actions of two or more individuals are coordinated and produce similar effects (e.g., music-making). Experience in such challenging contexts may refine skills of action attribution. Forty participants completed a novel finger-tapping task which parametrically manipulated the proportion of control that 'self' versus 'other' possessed over resulting auditory tones. Results showed that action misattribution peaked in the middle of the self-to-other continuum and was biased towards other. This pattern was related to both high hallucination-proneness and to low musical-experience. Findings suggest not only that causal ambiguity plays a key role in agency but also that action attribution abilities may improve with practice, potentially providing an avenue for remediation of the positive symptoms of schizophrenia.

Social cognitive functioning in prodromal psychosis: A meta-analysis

BACKGROUND

There is substantial evidence regarding a social cognitive deficit in schizophrenia, and it has been suggested to be a trait-marker of this disorder. However, a domain-by-domain analysis of social cognitive deficits in individuals at clinical high risk (CHR) for psychosis has not been performed.

METHOD

Electronic databases were searched for studies regarding social cognitive performance in individuals at CHR. The included social cognitive domains, which were classified based on the Social Cognition Psychometric Evaluation (SCOPE) initiative of the National Institute of Mental Health (NIMH), were as follows: theory of mind (ToM), social perception (SP), attributional bias (AB), and emotion processing (EP).

RESULTS

Twenty studies that included 1229 individuals at CHR and 825 healthy controls met the inclusion criteria. The overall effect size for social cognition was medium (g=-0.477). The largest effect size was identified for AB (g=-0.708). A medium effect size was identified for EP (g=-0.446) and ToM (g=-0.425), and small effects were identified for SP (g=-0.383).

CONCLUSION

This is the first quantitative domain-by-domain social cognitive meta-analysis regarding CHR individuals. The present study indicated that individuals at CHR exhibited significant impairments in all domains of social cognition compared with healthy controls, with the largest effect size identified for AB. The identification of social cognitive domains that reflect an increased risk for impending psychosis and of predictors of the conversion to psychosis via a longitudinal follow-up study is required.

Eating disorders and psychosis: Seven hypotheses

Psychotic disorders and eating disorders sometimes occur in the same person, and sometimes, but not always, at the same time. This can cause diagnostic confusion and uncertainty about treatment. This paper examines seven ways in which symptoms of both conditions can co-exist. The literature on this topic consists to a large extent of case reports, so that firm conclusions cannot be drawn from their examination. There is no consistent sequence in the co-occurrence of the two conditions-eating disorders sometimes precede, and sometimes follow the onset of psychosis. The advent of the psychosis, and sometimes the treatment of the psychosis can cure the eating disorder, but it can sometimes aggravate it. Psychosis is not necessarily a mark of severity in the course of an eating disorder, and food refusal can occur independent of severity in psychotic illness, but it can be a cause of death. There is some genetic association and some overlap of physiologic, cognitive and brain structure deficits in the two types of disorder. The connection between the two, however, remains speculative. The area of comorbidity and overlapping symptoms in psychiatry requires more research. Clinical recommendations include attention to the different individual ways in which these two disparate conditions often overlap.

Know thy sound: perceiving self and others in musical contexts

This review article provides a summary of the findings from empirical studies that investigated recognition of an action's agent by using music and/or other auditory information. Embodied cognition accounts ground higher cognitive functions in lower level sensorimotor functioning. Action simulation, the recruitment of an observer's motor system and its neural substrates when observing actions, has been proposed to be particularly potent for actions that are self-produced. This review examines evidence for such claims from the music domain. It covers studies in which trained or untrained individuals generated and/or perceived (musical) sounds, and were subsequently asked to identify who was the author of the sounds (e.g., the self or another individual) in immediate (online) or delayed (offline) research designs. The review is structured according to the complexity of auditory-motor information available and includes sections on: 1) simple auditory information (e.g., clapping, piano, drum sounds), 2) complex instrumental sound sequences (e.g., piano/organ performances), and 3) musical information embedded within audiovisual performance contexts, when action sequences are both viewed as movements and/or listened to in synchrony with sounds (e.g., conductors' gestures, dance). This work has proven to be informative in unraveling the links between perceptual-motor processes, supporting embodied accounts of human cognition that address action observation. The reported findings are examined in relation to cues that contribute to agency judgments, and their implications for research concerning action understanding and applied musical practice.

The neuroscience of free will: implications for psychiatry

Belief in free will has been a mainstay in philosophy throughout history, grounded in large part in our intuitive sense that we consciously control our actions and could have done otherwise. However, psychology and psychiatry have long sought to uncover mechanistic explanations for human behavior that challenge the notion of free will. In recent years, neuroscientific discoveries have produced a model of volitional behavior that is at odds with the notion of contra-causal free will and our sense of conscious agency. Volitional behavior instead appears to have antecedents in unconscious brain activity that is localizable to specific neuroanatomical structures. Updating notions of free will in favor of a continuous model of volitional self-control provides a useful paradigm to conceptualize and study some forms of psychopathology such as addiction and impulse control disorders. Similarly, thinking of specific symptoms of schizophrenia as disorders of agency may help to elucidate mechanisms of psychosis. Beyond clinical understanding and etiological research, a neuroscientific model of volitional behavior has the potential to modernize forensic notions of responsibility and criminal punishment in order to inform public policy. Ultimately, moving away from the language of free will towards the language of volitional control may result in an enhanced understanding of the very nature of ourselves.

Sensorimotor synchronization: a review of recent research (2006-2012)

Sensorimotor synchronization (SMS) is the coordination of rhythmic movement with an external rhythm, ranging from finger tapping in time with a metronome to musical ensemble performance. An earlier review (Repp, 2005) covered tapping studies; two additional reviews (Repp, 2006a, b) focused on music performance and on rate limits of SMS, respectively. The present article supplements and extends these earlier reviews by surveying more recent research in what appears to be a burgeoning field. The article comprises four parts, dealing with (1) conventional tapping studies, (2) other forms of moving in synchrony with external rhythms (including dance and nonhuman animals' synchronization abilities), (3) interpersonal synchronization (including musical ensemble performance), and (4) the neuroscience of SMS. It is evident that much new knowledge about SMS has been acquired in the last 7 years.

Self-attribution bias during continuous action-effect monitoring in patients with schizophrenia

The feeling of being the source and controller of one's actions and their effects in the outside world is an important aspect of our sense of self. Disturbances in this sense of agency (SoA) were observed in schizophrenia and have been linked to impairments in sensorimotor integration. We used a virtual-world action-monitoring paradigm to investigate the SoA in 20 schizophrenic patients and 18 healthy subjects. Participants continuously moved a virtual pen displayed on a computer screen using a touchpad device. The control they exceeded over the virtual pen was switched periodically between the participant and the computer. Participants were requested to monitor their actions and the effects on the virtual pen, and indicate loss or regain of control over the pen's movement by button presses. The numbers of erroneous external attribution of action effects (false negative agency judgements) and erroneous self-attribution (false positive agency judgements) were not significantly different in patients and healthy subjects. However, patients showed a significant increase in the duration of false negative agency judgements. Moreover, the number of false negative agency judgements as well as the number and the duration of false positive agency judgements were negatively correlated with the performance in cognitive tests (BACS) in the patient group only. Our findings indicate that the evaluation system to detect a mismatch between actions and their effects in the outside world is probably more rigid in schizophrenic patients, which leads to an increased self-attribution bias for action effects, as commonly found in delusions of control. The impairment in sensorimotor integration may be compensated for by stronger cognitive control.

The crisis of minimal self-awareness in schizophrenia: a meta-analytic review

Disturbances of the minimal self, characterized by abnormal sense of the body, body ownership and agency have been proposed as the phenomenological phenotype of schizophrenia. However, self-disturbances have not been extensively investigated, in part, due to the subjective nature of such processes, and the associated difficulty of studying these phenomena using empirical methodology. Of 115 potential studies on self-awareness in schizophrenia, a total of 25 studies met the inclusion criteria for the meta-analysis comprising 690 patients with schizophrenia and 979 healthy controls. We calculated Hedge's g to obtain a better estimate for the standardized mean difference in small samples. We identified significant basic self-disturbance in schizophrenia, as compared with healthy controls (25 studies, effect size=0.51). Additional comparison of three sub-categories of the sense of body ownership (4 studies, effect size=0.91), the sense of agency (15 studies, effect size=0.49), and self-reported subjective experiences (6 studies, effect size=0.57) also confirmed group differences. The complete set of 25 studies, and the studies in the sub-categories showed the statistical homogeneity of the characteristics. After a correction for potential publication bias using the trim-and-fill method, the main findings for all studies combined remained significant. Overall, patients with schizophrenia showed deficits in the sense of the minimal self, driven by abnormal sense of body ownership and sense of agency. Interestingly, the disturbed sense of agency in schizophrenia suggests an exaggerated self-consciousness rather than a diminished sense of self. Further research that utilizes sophisticated study designs is needed to examine the nature of self-disturbances in schizophrenia.

Reduced sense of agency in chronic schizophrenia with predominant negative symptoms

Self-disturbances in schizophrenia have been regarded as a fundamental vulnerability marker for this disease, and have begun to be studied from the standpoint of an abnormal "sense of agency (SoA)" in cognitive neuroscience. To clarify the nature of aberrant SoA in schizophrenia, it needs to be investigated in various clinical subtypes and stages. The residual type of chronic schizophrenia with predominant negative symptoms (NS) has never been investigated for SoA. Accordingly, we investigated SoA by an original agency attribution task in NS-predominant schizophrenia, and evaluated the dynamic interplay between the predictive and postdictive components of SoA in the optimal cue integration framework. We studied 20 patients with NS-predominant schizophrenia, and compared with 30 patients with paranoid-type schizophrenia and 35 normal volunteers. NS-predominant schizophrenia showed markedly diminished SoA compared to normal controls and paranoid-type schizophrenia, indicating a completely opposite direction in agency attribution compared with excessive SoA demonstrated in paranoid-type schizophrenia. Reduced SoA was detected in experimental studies of schizophrenia for the first time. According to the optimal cue integration framework, these results indicate that there was no increase in compensatory contributions of the postdictive processes despite the existence of inadequate predictions, contrary to the exaggerated postdictive component in paranoid-type schizophrenia.

Why must we attribute our own action to ourselves? Auditory hallucination like-experiences as the results both from the explicit self-other attribution and implicit regulation in speech

The sense of agency, which is the awareness that "I am the one who causes action," is important in understanding passive schizophrenic symptoms and bodily self-consciousness. However, this potential linkage between subjective self-other attribution (explicit agency) and automatic self-monitoring of an action (implicit agency) has not been examined fully. The present study included two experiments conducted with the same group of healthy participants (N=48) in order to examine explicit (Exp. 1) and implicit (Exp. 2) measures of the sense of agency in speech. Exp. 1 suggested that participants who tend not to attribute a fed-back voice to themselves (the other-attribution group) might have a stronger tendency toward auditory hallucinations, as measured by the Auditory Hallucination Experience Scale 17 (AHES-17). Furthermore, the results of Exp. 2 suggested that this other-attribution group might not utilize auditory feedback during speech production, indicating the expected link between explicit and implicit agency. These results are discussed in relation to the sense-of-agency model, wherein people are understood to construct the online "self" monitoring of action.

The coherent organization of mental life depends on mechanisms for context-sensitive gain-control that are impaired in schizophrenia

There is rapidly growing evidence that schizophrenia involves changes in context-sensitive gain-control and probabilistic inference. In addition to the well-known cognitive disorganization to which these changes lead, basic aspects of vision are also impaired, as discussed by other papers on this Frontiers Research Topic. The aim of this paper is to contribute to our understanding of such findings by examining five central hypotheses. First, context-sensitive gain-control is fundamental to brain function and mental life. Second, it occurs in many different regions of the cerebral cortex of many different mammalian species. Third, it has several computational functions, each with wide generality. Fourth, it is implemented by several neural mechanisms at cellular and circuit levels. Fifth, impairments of context-sensitive gain-control produce many of the well-known symptoms of schizophrenia and change basic processes of visual perception. These hypotheses suggest why disorders of vision in schizophrenia may provide insights into the nature and mechanisms of impaired reality testing and thought disorder in psychosis. They may also cast light on normal mental function and its neural bases. Limitations of these hypotheses, and ways in which they need further testing and development, are outlined.

The experience of agency: an interplay between prediction and postdiction

The experience of agency, i.e., the registration that I am the initiator of my actions, is a basic and constant underpinning of our interaction with the world. Whereas several accounts have underlined predictive processes as the central mechanism (e.g., the comparator model by C. Frith), others emphasized postdictive inferences (e.g., post-hoc inference account by D. Wegner). Based on increasing evidence that both predictive and postdictive processes contribute to the experience of agency, we here present a unifying but at the same time parsimonious approach that reconciles these accounts: predictive and postdictive processes are both integrated by the brain according to the principles of optimal cue integration. According to this framework, predictive and postdictive processes each serve as authorship cues that are continuously integrated and weighted depending on their availability and reliability in a given situation. Both sensorimotor and cognitive signals can serve as predictive cues (e.g., internal predictions based on an efferency copy of the motor command or cognitive anticipations based on priming). Similarly, other sensorimotor and cognitive cues can each serve as post-hoc cues (e.g., visual feedback of the action or the affective valence of the action outcome). Integration and weighting of these cues might not only differ between contexts and individuals, but also between different subject and disease groups. For example, schizophrenia patients with delusions of influence seem to rely less on (probably imprecise) predictive motor signals of the action and more on post-hoc action cues like e.g., visual feedback and, possibly, the affective valence of the action outcome. Thus, the framework of optimal cue integration offers a promising approach that directly stimulates a wide range of experimentally testable hypotheses on agency processing in different subject groups.