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Although hallucinations are important and frequent symptoms in major psychiatric and neurological diseases, little is known about their brain mechanisms. Hallucinations are unpredictable and private experiences, making their investigation, quantification and assessment highly challenging. A major shortcoming in hallucination research is the absence of methods able to induce specific and short-lasting hallucinations, which resemble clinical hallucinations, can be elicited repeatedly and vary across experimental conditions. By integrating clinical observations and recent advances in cognitive neuroscience with robotics, we have designed a novel device and sensorimotor method able to repeatedly induce a specific, clinically relevant hallucination: presence hallucination. Presence hallucinations are induced by applying specific conflicting (spatiotemporal) sensorimotor stimulation including an upper extremity and the torso of the participant. Another, MRI-compatible, robotic device using similar sensorimotor stimulation permitted the identification of the brain mechanisms of these hallucinations. Enabling the identification of behavioral and a frontotemporal neural biomarkers of hallucinations, under fully controlled experimental conditions and in real-time, this method can be applied in healthy participants as well as patients with schizophrenia, neurodegenerative disease or other hallucinations. The execution of these protocols requires intermediate-level skills in cognitive neuroscience and MRI processing, as well as minimal coding experience to control the robotic device. These protocols take ~3 h to be completed., (© 2022. Springer Nature Limited.)

Psychosis, characterized by hallucinations and delusions, is a common feature of psychiatric disease, especially schizophrenia. One prominent theory posits that psychosis is driven by abnormal sensorimotor predictions leading to the misattribution of self-related events. This misattribution has been linked to passivity experiences (PE), such as loss of agency and, more recently, to presence hallucinations (PH), defined as the conscious experience of the presence of an alien agent while no person is actually present. PH has been observed in schizophrenia, Parkinson's disease, and neurological patients with brain lesions and, recently, the brain mechanisms of PH (PH-network) have been determined comprising bilateral posterior middle temporal gyrus (pMTG), inferior frontal gyrus (IFG), and ventral premotor cortex (vPMC). Given that the experience of an alien agent is a common feature of PE, we here analyzed the functional connectivity within the PH-network in psychotic patients with (N = 39) vs without PE (N = 26). We observed reduced fronto-temporal functional connectivity in patients with PE compared to patients without PE between the right pMTG and the right and left IFG of the PH-network. Moreover, when seeding from these altered regions, we observed specific alterations with brain regions commonly linked to auditory-verbal hallucinations (such as Heschl's gyrus). The present connectivity findings within the PH-network extend the disconnection hypothesis for hallucinations to the specific case of PH and associates the PH-network with key brain regions for frequent psychotic symptoms such as auditory-verbal hallucinations, showing that PH are relevant to the study of the brain mechanisms of psychosis and PE., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.)

Meta-analyses and reviews on cognitive disorders in schizophrenia have shown that the most robust and common cognitive deficits are found in episodic memory and executive functions. More complex memory domains, such as autobiographical memory (AM), are also impaired in schizophrenia, but such impairments are reported less often despite their negative impact on patients' outcome. In contrast to episodic memory, assessed in laboratory tasks, memories of past personal events are much more complex and directly relate to the self. The meta-analysis included 20 studies, 571 patients with schizophrenia spectrum disorder, and 503 comparison subjects. It found moderate-to-large effect sizes with regard to the 3 parameters commonly used to assess AM: memory specificity (g = -0.97), richness of detail (g = -1.40), and conscious recollection (g = -0.62). These effect sizes were in the same range as those found in other memory domains in schizophrenia; for this reason, we propose that defective memories of personal past events should be regarded as a major cognitive impairment in this illness., (© The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Self-narratives of patients have received increasing interest in schizophrenia since they offer unique material to study patients' subjective experience related to their illness, in particular the alteration of self that accompanies schizophrenia. In this study, we investigated the life narratives and the ability to integrate and bind memories of personal events into a coherent narrative in 27 patients with schizophrenia and 26 controls. Four aspects of life narratives were analyzed: coherence with cultural concept of biography, temporal coherence, causal-motivational coherence and thematic coherence. Results showed that in patients cultural biographical knowledge is preserved, whereas temporal coherence is partially impaired. Furthermore, causal-motivational and thematic coherence are significantly impaired: patients have difficulties explaining how events have modeled their identity, and integrating different events along thematic lines. Impairment of global causal-motivational and thematic coherence was significantly correlated with patients' executive dysfunction, suggesting that cognitive impairment observed in patients could affect their ability to construct a coherent narrative of their life by binding important events to their self. This study provides new understanding of the cognitive deficits underlying self-disorders in patients with schizophrenia. Our findings suggest the potential usefulness of developing new therapeutic interventions to improve autobiographical reasoning skills.

Autobiographical memory deficits in schizophrenia have a significant impact on patients' daily life. Our study was aimed at testing the effectiveness of a specific cueing (SC) method for improving autobiographical memory recall in patients with schizophrenia, particularly the phenomenological details of their memories. Twenty-five patients with schizophrenia and 25 comparison participants took part in the study. They recalled 6 specific autobiographical events which occurred during 3 different life periods. After each memory recall, participants were given a general cue which allowed them to add further information to their narration. The SC was then applied by means of a series of specific questions to elicit more precise memory detail. The overall memory specificity as well as the number and richness of 5 categories of memory detail (perceptual/sensory, temporal, contextual, emotional, and cognitive) were assessed before and after the SC phase. Before SC, patients' memories were less specific and less detailed. SC had a beneficial effect on patients' memory recall. The overall memory specificity of patients improved. The gain in the number and richness of memory details was comparable between patients and comparison participants. The difference between groups in terms of the number of memory details was not significant. Richness of details was still lower in patients, except for emotional and cognitive details, which were similarly rich in both groups. The cueing method reduces the autobiographical memory impairment of patients with schizophrenia and paves the way for developing specific cognitive remediation therapies to help patients in their daily life., (Copyright © 2013. Published by Elsevier B.V.)

There is growing interest in clinical research regarding the visual perspective adopted during memory retrieval, because it reflects individuals' self-attitude towards their memories of past personal events. Several autobiographical memory deficits, including low specificity of personal memories, have been identified in schizophrenia, but visual perspective during autobiographical memory retrieval has not yet been investigated in patients. The aim of this study was therefore to investigate the visual perspective with which patients visualize themselves when recalling autobiographical memories and to assess the specificity of their memories which is a major determinant of visual perspective. Thirty patients with schizophrenia and 30 matched controls recalled personal events from 4 life periods. After each recall, they were asked to report their visual perspective (Field or Observer) associated with the event. The specificity of their memories was assessed by independent raters. Our results showed that patients reported significantly fewer Field perspectives than comparison participants. Patients' memories, whether recalled with Field or Observer perspectives, were less specific and less detailed. Our results indicate that patients with schizophrenia adopt Field perspectives less frequently than comparison participants, and that this may contribute to a weakened sense of the individual of being an actor of his past events, and hence to a reduced sense of self. They suggest that this may be related to low specificity of memories and that all the important aspects involved in re-experiencing autobiographical events are impaired in patients with schizophrenia., (© 2013 Elsevier B.V. All rights reserved.)

Although schizophrenia alters the sense of personal identity, little is known about the impact of illness-related autobiographical events on patients' self-representation. We investigated self-defining memories (SDM) in 24 patients with schizophrenia and 24 controls to explore how illness-related SDM were integrated into the self at both the cognitive (how participants are able to give a meaning to past events: meaning making) and affective levels (how participants can re-experience past negative events as less negative: redemption and benefaction effects). We found that 26% of freely recalled SDM referred to their illness in patients. Further, while meaning making was impaired in patients for both illness-related and other SDM, illness-related SDM were characterized by a higher redemption and benefaction effects than other SDM. Our results highlight that despite a reduced ability to give a meaning to illness-related episodes, emotional processing seems to allow these events to become positively integrated into patients' life stories. This study provides new findings about the construction of the self in relation to psychotic episodes in patients with schizophrenia. We discuss clinical implications of our results that are helpful to guide cognitive interventions., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Cognitive disorders are considered as a core symptom of schizophrenia. Importantly, episodic autobiographical memory deficits are strongly related to patients' social dysfunction. Although the cognitive mechanisms underlying autobiographical memory deficit are highly important to open the door for specific cognitive remediation, they are yet to be understood. The present study focused on event segmentation to check to which extent possible impairments in temporal ordering and segmenting in patients hinder memories construction. Twenty-seven patients with schizophrenia and 27 matched controls took part in an outdoor circuit while wearing a wearable camera. A week later, their memory and the temporal organization of this event have been assessed. Results showed that patients, compared with control participants, reported a reduced amount of details, especially less actions with interaction related to the event. Contrary to our initial hypotheses, event segmentation abilities in patients were not affected. The relationship between event segmentation and memory is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Disturbances of perception of subjective time have been described in schizophrenia but have not been experimentally studied until now. We investigated how patients with schizophrenia estimate the subjective temporal distance (TD) of past personal events, i.e. how these events are perceived as subjectively close or distant in time. Twenty-five patients with schizophrenia and 25 control participants recalled 24 autobiographical memories from four different life periods. They estimated the subjective TD and rated the amount of detail of each memory. Results showed that patients with schizophrenia had a distorted perception of subjective TD. Their memories were significantly less detailed than those of controls and, unlike control participants, the amount of memory detail was not significantly correlated with subjective TD. Poor access to memory detail may account for distortions of perception of subjective time in patients with schizophrenia. [Copyright &y& Elsevier]

Abstract: Schizophrenia is a severe mental illness affecting sense of identity. Autobiographical memory deficits observed in schizophrenia could contribute to this altered sense of identity. The ability to give a meaning to personally significant events (meaning making) is also critical for identity construction and self-coherence. Twenty-four patients with schizophrenia and 24 control participants were asked to recall five self-defining memories. We assessed meaning making in participants’ narratives (spontaneous meaning making) and afterwards asked them explicitly to give a meaning to their memories (cued meaning making). We found that both spontaneous and cued meaning making were impaired in patients with schizophrenia. This impairment was correlated with executive dysfunctions and level of negative symptoms. Our results suggest that patients’ difficulties in drawing lessons about past experiences could contribute to explain the lack of coherence observed in their life trajectories and their impaired social adjustment abilities. Implications for psychotherapy are also discussed. [Copyright &y& Elsevier]