A neural model of the loss of self in schizophrenia

Hippocampus-Centered Network Is Associated With Positive Symptom Alleviation in Patients With First-Episode Psychosis

BACKGROUND

Previous functional magnetic resonance imaging studies have reported widespread brain functional connectivity alterations in patients with psychosis. These studies have mostly used either resting-state or simple-task paradigms, thereby compromising experimental control or ecological validity, respectively. Additionally, in a conventional functional magnetic resonance imaging intrasubject functional connectivity analysis, it is difficult to identify which connections relate to extrinsic (stimulus-induced) and which connections relate to intrinsic (non-stimulus-related) neural processes.

METHODS

To mitigate these limitations, we used intersubject functional connectivity (ISFC) to analyze longitudinal functional magnetic resonance imaging data collected while 36 individuals with first-episode psychosis (FEP) and 29 age- and sex-matched population control participants watched scenes from the fantasy movie Alice in Wonderland at baseline and again at 1-year follow-up. Furthermore, to allow unconfounded comparison and to overcome possible circularity of ISFC, we introduced a novel approach wherein ISFC in both the FEP and population control groups was calculated with respect to an independent group of participants (not included in the analyses).

RESULTS

Using this independent-reference ISFC approach, we found an interaction effect wherein the independent-reference ISFC in individuals with FEP, but not in the control group participants, was significantly stronger at baseline than at follow-up in a network centered in the hippocampus and involving thalamic, striatal, and cortical regions, such as the orbitofrontal cortex. Alleviation of positive symptoms, particularly delusions, from baseline to follow-up was correlated with decreased network connectivity in patients with FEP.

CONCLUSIONS

These findings link deviation of naturalistic information processing in the hippocampus-centered network to positive symptoms.

Relating movement markers of schizophrenia to self-experience-a mixed-methods study

Introduction

Basic self-disorders on the one hand and motor symptoms on the other hand are discussed as endophenotypes of schizophrenia psychopathology. However, the systematic interaction between motor symptoms and the self-experience of patients is rarely studied.

Methods

In a previous study we defined motor markers of schizophrenia via a data-driven analysis of patients' gait patterns. In this study, we related the movement markers to measures of basic self-disorder obtained with EASE interviews. We substantiated the correlations with a qualitative content analysis of the interviews of a subset of four patients. We related qualitative and quantitative data on an intra- and interpersonal level.

Results

Our results suggest an association between the previously defined, theory-independent movement markers and basic self-disorders, specifically in the domain of cognition, self-experience and bodily experiences. While movement marker manifestation was not precisely reflected in the individuals' descriptions of anomalous self- and body experience, we found clear trends of more and more intense descriptions with increasing movement marker scores, when looking at specific experiences, such as hyper reflexivity.

Discussion

These results foster an integrated view of the patient and could stimulate therapeutic approaches aiming at an improvement of self- and body-experience of patients with schizophrenia.

Approach to impaired corollary discharge in patients with schizophrenia: An analysis of self-induced somatosensory evoked potentials and fields

Background

Difficulty in distinguishing between self-generated actions and those generated by others is a core feature of schizophrenia. This is thought to be underpinned by the failure of corollary discharge. However, few studies have investigated these events using somatosensory evoked potentials (SEPs) and somatosensory evoked magnetic fields (SEFs).

Methods

The study included 15 right-handed patients with schizophrenia and 16 healthy controls. SEP and SEF were elicited by electrical stimuli to the left median nerve at intervals of 1–3 s. In the external condition, stimuli were externally induced by a machine. In the self-condition, stimuli were induced by tapping the participants’ own right index finger. Peak amplitude at C4’ in SEP and root mean square in 10 channels on the right primary somatosensory area in SEF were analyzed.

Results

Although there was a significant main effect of condition at N20m, and a significant main effect of condition and group at P30m, no significant interactions of condition and group were found in either N20m or P30m. The post-hoc Wilcoxon signed-rank test revealed that the peak value of P30m in the external condition was significantly higher than that in the self-condition in the healthy control group only. In addition, there was a significant positive correlation between the peak value of P30m in the self-condition and a positive symptom score.

Conclusion

In the current study, we did not find abnormalities of corollary discharge in primary sensory areas in patients with schizophrenia. Further investigations with more cases may reveal the possibility of corollary discharge disturbance in the primary sensory cortex.

Self and world experience in non-affective first episode of psychosis

A disturbance of "minimal self," - of the immediate sense of mine-ness inherent in experience-is hypothesized to be the core disturbance in schizophrenia. Research with the Examination of Anomalous Self Experience (EASE) has demonstrated the selective aggregation of anomalous self-experiences in the schizophrenia spectrum. Conceptual research suggests that anomalous world experiences, including changes in the experience of space, time, and other persons, occur alongside anomalous self-experiences and are an important aspect of subjectivity in schizophrenia. The Examination of Anomalous World Experience (EAWE) is a recently published interview format designed to explore changes in world experience in schizophrenia. In the current study, 24 hospital outpatients with non-affective first-episode psychosis and 24 healthy-control participants were assessed with the EAWE and the EASE. First episode psychosis patients had total EAWE and EASE scores that were both, on average, significantly higher than the healthy-control group. EAWE and EASE scores were highly correlated, even after removing overlapping items. The distribution of EAWE items and subtypes in the first-episode psychosis sample was heterogeneous. We conclude that anomalous world experiences represent a relevant aspect of first-episode psychosis, and that they may be related to the self-disturbances thought to underlie schizophrenia spectrum disorders.

Schizophrenia and Corollary Discharge: A Neuroscientific Overview and Translational Implications

Corollary discharge mechanism refers to the suppression of sensory consequences of self-generated actions; a process that serves to distinguish between self and non-self based on discrimination of origination of action. It explains, say for example, why we cannot tickle ourselves. This review discusses how corollary discharge model is an essential neural integration mechanism central to the motor functioning of animal kingdom. In this article, research conducted in the field of corollary discharge has been reviewed to understand the neuroanatomical and neurophysiological basis of corollary discharge and gain insight into the biochemical basis of its dysfunction. This review article also explores the role of corollary discharge and its dysfunction in the presentation of symptoms of schizophrenia, discussing the findings from corollary discharge studies on schizophrenia population. Lastly, the link between schizophrenia psychopathology and corollary discharge dysfunction has been highlighted, and an attempt has been made to establish a case for correction of corollary discharge deficit in schizophrenia through neuromodulation.

Towards integrating phenomenology and neurocognition: Possible neurocognitive correlates of basic self-disturbance in schizophrenia

Phenomenological research indicates that disturbance of the basic sense of self may be a core phenotypic marker of schizophrenia spectrum disorders. Basic self-disturbance refers to disruption of the sense of ownership of experience and agency of action and is associated with a variety of anomalous subjective experiences. Little is known about the neurocognitive correlates of basic self-disturbance. In this paper, we review recent phenomenological and neurocognitive research and point to a convergence of these approaches around the concept of self-disturbance. Specifically, we propose that subjective anomalies associated with basic self-disturbance may be associated with: 1. source monitoring deficits, which may contribute particularly to disturbances of “ownership” and “mineness” (the phenomenological notion of presence) and 2. aberrant salience, and associated disturbances of memory, prediction, and attention processes, which may contribute to hyper-reflexivity, disturbed “grip” or “hold” on the perceptual and conceptual field, and disturbances of intuitive social understanding (“common sense”). These two streams of research are reviewed in turn before considering ways forward in integrative models, particularly regarding the role of early neurodevelopmental disturbances, primary versus secondary disturbances, and the state versus trait nature of such pathology. Empirical studies are required in a variety of populations in order to test the proposed associations between phenomenological and neurocognitive aspects of self-disturbance in schizophrenia. An integration of findings across the phenomenological and neurocognitive domains would represent a significant advance in the understanding of schizophrenia and possibly enhance early identification and intervention strategies.

Phenomenology and neurobiology of self disorder in schizophrenia: Primary factors

Schizophrenia is a heterogeneous syndrome, varying between persons and over course of illness. In this and a companion article, we argue that comprehension of this condition or set of conditions may require combining a phenomenological perspective emphasizing disorders of basic-self experience ("ipseity disturbance") with a multidimensional appreciation of possible neurobiological correlates--both primary and secondary. Previous attempts to link phenomenology and neurobiology generally focus on a single neurocognitive factor. We consider diverse aspects of schizophrenia in light of a diverse, albeit interacting, set of neurocognitive abnormalities, examining both synchronic (structural) interdependence and diachronic (temporal) succession. In this article we focus on the primary or foundational role of early perceptual and motoric disturbances that affect perceptual organization and especially intermodal or multisensory perceptual integration (“perceptual dys-integration”). These disturbances are discussed in terms of their implications for three interconnected aspects of selfhood in schizophrenia, primary forms of: disrupted "hold" or "grip" on the world, hyperreflexivity, diminished self-presence (self-affection). Disturbances of organization or integration imply forms of perceptual incoherence or diminished cognitive coordination. The effect is to disrupt one's ability to apprehend the world in holistic, vital, or contextually grounded fashion, or to fully identify with or experience the unity of one's own body or thinking--thereby generating an early and profound (albeit often subtle) disruption or diminishment of basic or core self and of the sense of existing in a coherent world. We discuss interrelationships or possible complementarities between these three aspects, and consider their relevance for a neurodevelopmental account of schizophrenia.

Altered Basal Ganglia Network Integration in Schizophrenia

The basal ganglia involve in a range of functions that are disturbed in schizophrenia patients. This study decomposed the resting-state data of 28 schizophrenia patients and 31 healthy controls with spatial independent component analysis and identified increased functional integration in the bilateral caudate nucleus in schizophrenia patients. Further, the caudate nucleus in patients showed altered functional connection with the prefrontal area and cerebellum. These results identified the importance of basal ganglia in schizophrenia patients. Clinical Trial Registration: Chinese Clinical Trial Registry. Registration number ChiCTR-RCS-14004878.

Understanding schizophrenia as a disorder of consciousness: biological correlates and translational implications from quantum theory perspectives

From neurophenomenological perspectives, schizophrenia has been conceptualized as "a disorder with heterogeneous manifestations that can be integrally understood to involve fundamental perturbations in consciousness". While these theoretical constructs based on consciousness facilitate understanding the 'gestalt' of schizophrenia, systematic research to unravel translational implications of these models is warranted. To address this, one needs to begin with exploration of plausible biological underpinnings of "perturbed consciousness" in schizophrenia. In this context, an attractive proposition to understand the biology of consciousness is "the orchestrated object reduction (Orch-OR) theory" which invokes quantum processes in the microtubules of neurons. The Orch-OR model is particularly important for understanding schizophrenia especially due to the shared 'scaffold' of microtubules. The initial sections of this review focus on the compelling evidence to support the view that "schizophrenia is a disorder of consciousness" through critical summary of the studies that have demonstrated self-abnormalities, aberrant time perception as well as dysfunctional intentional binding in this disorder. Subsequently, these findings are linked with 'Orch-OR theory' through the research evidence for aberrant neural oscillations as well as microtubule abnormalities observed in schizophrenia. Further sections emphasize the applicability and translational implications of Orch-OR theory in the context of schizophrenia and elucidate the relevance of quantum biology to understand the origins of this puzzling disorder as "fundamental disturbances in consciousness".

Do deficits in the magnocellular priming underlie visual derealization phenomena? Preliminary neurophysiological and self-report results in first-episode schizophrenia patients

BACKGROUND

Early visual impairments probably partially caused by impaired interactions between magnocellular (M) and parvocellular (P) pathways (M priming deficit), and disturbances of basic self-awareness or self-disorders (SDs) are core features of schizophrenia. The relationships between these features have not yet been studied. We hypothesized that the M priming was impaired in first-episode patients and that this deficit was associated with visual aspects of SDs.

AIM

To investigate early visual processing in a sample of first-episode schizophrenia patients and to explore the relationships between M and P functioning and visual aspects of SDs addressed by the Examination of Anomalous Self-Experience (EASE) interview.

METHOD

Nine stimulating conditions were used to investigate M and P pathways and their interaction in a pattern reversal visually evoked potential (VEP) paradigm. N80 at mixed M- and P-conditions was used to investigate magnocellular priming. Generators were analyzed using source localization (Brain Electrical Source Analysis software: BESA). VEPs of nineteen first-episode schizophrenia patients were compared to those of twenty matched healthy controls by a bootstrap resample procedure. Visual aspects of SDs were analyzed through a factor analysis to separate symptom clusters of derealization phenomena. Thereafter, the associations between the main factors and the N80 component were explored using linear mixed models.

RESULTS

Factor analyses separated two EASE factors ("distance to the world", and "intrusive world"). The N80 component was represented by a single dipole located in the occipital visual cortex. The bootstrap analysis yielded significant amplitude reductions and prolonged latencies in first-episode patients relative to controls in response to mixed M-P conditions, and normal amplitudes and latencies in response to isolated P- and M-biased stimulation. Exploratory analyses showed significant negative correlations between the N80 amplitude values at mixed M-P conditions and the EASE factor "distance to the world", i.e. relatively higher amplitudes in the patient group were associated with higher subjective perceived derealization ("distance to the world").

CONCLUSIONS

The early VEP component N80 evoked by mixed M-P conditions is assumed to be a correlate of M priming, and showed reduced amplitudes and longer latencies in first-episode patients. It probably reflects a hypoactivation of the M-pathway. The negative association between visual SDs (derealization phenomena characterized by visual experiences of being more distant to the world), and the M priming deficit was counterintuitive. It might indicate a dysregulated activity of the M-pathway in patients with SDs. Further research is needed to better understand this preliminary finding.

Neurophysiological correlates of various mental perspectives

A common view of consciousness is that our mind presents emotions, experiences, and images in an internal mental (re-)presentation space which in a state of wakefulness is triggered by the world outside. Consciousness can be defined as the observation of this inner mental space. We propose a new model, in which the state of the conscious observer is defined by the observer’s mental position and focus of attention. The mental position of the observer can either be within the mental self (intrapersonal space), in the mental outer world (extrapersonal space) or in an empathic connection, i.e., within the intrapersonal space of another person (perspective taking). The focus of attention can be directed toward the self or toward the outside world. This mental space model can help us to understand the patterns of relationships and interactions with other persons as they occur in social life. To investigate the neurophysiological correlates and discriminability of the different mental states, we conducted an EEG experiment measuring the brain activity of 16 subjects via 64 electrodes while they engaged in different mental positions (intrapersonal, extrapersonal, perspective taking) with different attentional foci (self, object). Compared to external mental locations, internal ones showed significantly increased alpha2 power, especially when the observer was focusing on an object. Alpha2 and beta2 were increased in the empathic condition compared to the extrapersonal perspective. Delta power was significantly higher when the attentional focus was directed toward an object in comparison to the participant’s own self. This exploratory study demonstrates highly significant differences between various mental locations and foci, suggesting that the proposed categories of mental location and intra- and interpersonal attentional foci are not only helpful theoretical concepts but are also physiologically relevant and therefore may relate to basic brain processing mechanisms.

What are the neurocognitive correlates of basic self-disturbance in schizophrenia?: Integrating phenomenology and neurocognition. Part 1 (Source monitoring deficits)

Phenomenological research indicates that disturbance of the basic sense of self may be a core phenotypic marker of schizophrenia spectrum disorders. Basic self-disturbance refers to disruption of the sense of ownership of experience and agency of action and is associated with a variety of anomalous subjective experiences. Little is known about the neurocognitive underpinnings of basic self-disturbance. In these two theoretical papers (of which this is Part 1), we review some recent phenomenological and neurocognitive research and point to a convergence of these approaches around the concept of self-disturbance. Specifically, we propose that subjective anomalies associated with basic self-disturbance may be associated with: 1. source monitoring deficits, which may contribute particularly to disturbances of "ownership" and "mineness" (the phenomenological notion of presence or self-affection) and 2. aberrant salience, and associated disturbances of memory, prediction and attention processes, which may contribute to hyper-reflexivity, disturbed "grip" or "hold" on the perceptual and conceptual field, and disturbances of intuitive social understanding ("common sense"). In this paper (Part 1) we focus on source monitoring deficits. Part 2 (this issue) addresses aberrant salience. Empirical studies are required in a variety of populations in order to test these proposed associations between phenomenological and neurocognitive aspects of self-disturbance in schizophrenia. An integration of findings across the phenomenological and neurocognitive "levels" would represent a significant advance in the understanding of schizophrenia and possibly enhance early identification and intervention strategies.

Introspection and schizophrenia: a comparative investigation of anomalous self experiences

This paper offers a comparative investigation of anomalous self-experiences common in schizophrenia (defined in Examination of Anomalous Self Experiences (EASE) instrument) and those of normal individuals in an intensely introspective orientation (early 20th-century "introspectionist" psychology). The latter represent a relatively pure manifestation of certain forms of exaggerated self-consciousness ("hyperreflexivity"), one facet of the disturbance of core- or minimal-self ("ipseity" disturbance) postulated as central in schizophrenia. Significant similarities with schizophrenia-like experience were found but important differences also emerged. Affinities included feelings of passivity, fading of self or world, and alienation from thoughts, feelings, or lived-body. Differences involved confusion between self and world and severe dislocation or erosion of first-person perspective, qualities unique to schizophrenia. The purpose is threefold: 1, place the putatively schizophrenic experiences of self-disorder in a broader, comparative context; 2, evaluate hypotheses concerning core processes in schizophrenia; 3, orient investigation of possible pathogenetic pathways as well as psychotherapeutic interventions.

Anomalous self-experience in depersonalization and schizophrenia: a comparative investigation

Various forms of anomalous self-experience can be seen as central to schizophrenia and other psychiatric disorders. We examined similarities and differences between anomalous self-experiences common in schizophrenia-spectrum disorders, as listed in the EASE (Examination of Anomalous Self Experiences), and those described in published accounts of severe depersonalization. Our aims were to consider anomalous self-experience in schizophrenia in a comparative context, to refine and enlarge upon existing descriptions of experiential disturbances in depersonalization, and to explore hypotheses concerning a possible core process in schizophrenia (diminished self-affection, an aspect of "ipseity" or minimal self). Numerous affinities between depersonalization and schizophrenia-spectrum experience were found: these demonstrate that rather pure forms of diminished self-affection (depersonalization) can involve many experiences that resemble those of schizophrenia. Important discrepancies also emerged, suggesting that more automatic or deficiency-like factors--probably involving self/world or self/other confusion and erosion of first-person perspective--are more distinctive of schizophrenia-spectrum disorders.

Basic self-disturbance predicts psychosis onset in the ultra high risk for psychosis "prodromal" population

INTRODUCTION

Phenomenological research indicates that disturbance of the basic sense of self may be a core phenotypic marker of schizophrenia spectrum disorders. Basic self-disturbance refers to a disruption of the sense of ownership of experience and agency of action and is associated with a variety of anomalous subjective experiences. In this study, we investigated the presence of basic self-disturbance in an "ultra high risk" (UHR) for psychosis sample compared with a healthy control sample and whether it predicted transition to psychotic disorder.

METHODS

Forty-nine UHR patients and 52 matched healthy control participants were recruited to the study. Participants were assessed for basic self-disturbance using the Examination of Anomalous Self-Experience (EASE) instrument. UHR participants were followed for a mean of 569 days.

RESULTS

Levels of self-disturbance were significantly higher in the UHR sample compared with the healthy control sample (P < .001). Cox regression indicated that total EASE score significantly predicted time to transition (P < .05) when other significant predictors were controlled for. Exploratory analyses indicated that basic self-disturbance scores were higher in schizophrenia spectrum cases, irrespective of transition to psychosis, than nonschizophrenia spectrum cases.

DISCUSSION

The results indicate that identifying basic self-disturbance in the UHR population may provide a means of further "closing in" on individuals truly at high risk of psychotic disorder, particularly of schizophrenia spectrum disorders. This may be of practical value by reducing inclusion of "false positive" cases in UHR samples and of theoretical value by shedding light on core phenotypic features of schizophrenia spectrum pathology.