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Jimenez AM, Green MF. Disturbance at the self-other boundary in schizophrenia: Linking phenomenology to clinical neuroscience. Schizophr Res 2024; 272:51-60. [PMID: 39190982 DOI: 10.1016/j.schres.2024.07.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 07/21/2024] [Accepted: 07/24/2024] [Indexed: 08/29/2024]
Abstract
In this selective review, we describe the current neuroscientific literature on disturbances of the self-other boundary in schizophrenia as they relate to structural and experiential aspects of the self. Within these two broad categories, the structural self includes body ownership and agency, and the experiential self includes self-reflection, source monitoring, and self-referential and autobiographical memory. Further, we consider how disturbances in these domains link to the phenomenology of schizophrenia. We identify faulty internal predictive coding as a potential mechanism of disturbance in body ownership and agency, which results in susceptibility to bias (over- or under-attributing outcomes to one's own actions or intentions). This is reflected in reduced activity in the temporoparietal junction (TPJ), a heteromodal association area implicated in several aspects of self-other processing, as well as reduced fronto-parietal functional connectivity. Deficits of the experiential self in schizophrenia may stem from a lack of salience of self-related information, whereby the mental representation of self is not as rich as in healthy controls and therefore does not result in the same level of privileged processing. As a result, memory for self-referential material and autobiographical memory processes is impaired, which hinders creation of a cohesive life narrative. Impairments of the experiential self implicate abnormal activation patterns along the cortical midline, including medial prefrontal cortex and posterior cingulate/precuneus, as well as TPJ. In fact, TPJ appears to be involved in all the reviewed aspects of the self-other disturbance. We conclude with suggestions for future work, including implications for interventions with critical timing considerations.
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Affiliation(s)
- Amy M Jimenez
- Department of Veterans Affairs, Desert Pacific Mental Illness Research, Education, and Clinical Center, USA; VA Rehabilitation R&D Center on Enhancing Community Integration for Homeless Veterans, USA; Jane and Terry Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Biobehavioral Sciences, UCLA, USA.
| | - Michael F Green
- Department of Veterans Affairs, Desert Pacific Mental Illness Research, Education, and Clinical Center, USA; VA Rehabilitation R&D Center on Enhancing Community Integration for Homeless Veterans, USA; Jane and Terry Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Biobehavioral Sciences, UCLA, USA
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2
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Sabbah SG, Northoff G. Global neural self-disturbance in schizophrenia: A systematic fMRI review. Schizophr Res 2024; 269:163-173. [PMID: 38820980 DOI: 10.1016/j.schres.2024.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/04/2024] [Accepted: 05/23/2024] [Indexed: 06/02/2024]
Abstract
There is a general consensus that schizophrenia (SZ) is characterized by major changes in the sense of self. Phenomenological studies suggest that these changes in the sense of self stem from a basic disturbance, hence the term 'basic self-disturbance'. While imaging studies demonstrate changes in various regions during self-focused tasks, the exact neural correlates of such basic self-disturbances remain unclear. If the self-disturbance is indeed basic and thereby underlies all other symptoms, one would expect it to be related to more global rather than local changes in the brain. Testing this hypothesis, we conducted a systematic review of fMRI studies on self in SZ. Our main findings are 1. Abnormal activity related to the self can be observed in a variety of different regions ranging from higher-order transmodal to lower-order unimodal regions, 2. These findings hold true across different tasks including self-reflection, self-referentiality, and self-agency, and 3. The global neural abnormalities related to the self in SZ correspond to all layers of the self, predominantly the mental and exteroceptive self. Such global neural disturbance of self converges well with the basic self-disturbance as described in phenomenology.
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Affiliation(s)
- Sami George Sabbah
- Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada; The Royal's Institute of Mental Health Research & University of Ottawa, Brain and Mind Research Institute, Centre for Neural Dynamics, Faculty of Medicine, University of Ottawa, 145 Carling Avenue, Rm. 6435, Ottawa, ON, K1Z 7K4, Canada
| | - Georg Northoff
- The Royal's Institute of Mental Health Research & University of Ottawa, Brain and Mind Research Institute, Centre for Neural Dynamics, Faculty of Medicine, University of Ottawa, 145 Carling Avenue, Rm. 6435, Ottawa, ON, K1Z 7K4, Canada
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3
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Clinical observations and neuroscientific evidence tell a similar story: Schizophrenia is a disorder of the self-other boundary. Schizophr Res 2022; 242:45-48. [PMID: 35027299 DOI: 10.1016/j.schres.2021.12.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 12/13/2022]
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4
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Zhang J, Liu T, Shi Z, Tan S, Suo D, Dai C, Wang L, Wu J, Funahashi S, Liu M. Impaired Self-Referential Cognitive Processing in Bipolar Disorder: A Functional Connectivity Analysis. Front Aging Neurosci 2022; 14:754600. [PMID: 35197839 PMCID: PMC8859154 DOI: 10.3389/fnagi.2022.754600] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 01/10/2022] [Indexed: 11/21/2022] Open
Abstract
Patients with bipolar disorder have deficits in self-referenced information. The brain functional connectivity during social cognitive processing in bipolar disorder is unclear. Electroencephalogram (EEG) was recorded in 23 patients with bipolar disorder and 19 healthy comparison subjects. We analyzed the time-frequency distribution of EEG power for each electrode associated with self, other, and font reflection conditions and used the phase lag index to characterize the functional connectivity between electrode pairs for 4 frequency bands. Then, the network properties were assessed by graph theoretic analysis. The results showed that bipolar disorder induced a weaker response power and phase lag index values over the whole brain in both self and other reflection conditions. Moreover, the characteristic path length was increased in patients during self-reflection processing, whereas the global efficiency and the node degree were decreased. In addition, when discriminating patients from normal controls, we found that the classification accuracy was high. These results suggest that patients have impeded integration of attention, memory, and other resources of the whole brain, resulting in a deficit of efficiency and ability in self-referential processing.
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Affiliation(s)
- Jian Zhang
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, China
| | - Tiantian Liu
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Zhongyan Shi
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Shuping Tan
- Center for Psychiatric Research, Beijing Huilongguan Hospital, Beijing, China
| | - Dingjie Suo
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Chunyang Dai
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Li Wang
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
- *Correspondence: Li Wang,
| | - Jinglong Wu
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, China
- Cognitive Neuroscience Laboratory, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Shintaro Funahashi
- Advanced Research Institute of Multidisciplinary Sciences, Beijing Institute of Technology, Beijing, China
| | - Miaomiao Liu
- School of Psychology, Shenzhen University, Shenzhen, China
- Miaomiaos Liu,
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5
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Klock L, Voss M, Weichenberger M, Kathmann N, Kühn S. The Thought From the Machine: Neural Basis of Thoughts With a Coherent and Diminished Sense of Authorship. Schizophr Bull 2021; 47:1631-1641. [PMID: 34387697 PMCID: PMC8530403 DOI: 10.1093/schbul/sbab074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Patients with schizophrenia who experience inserted thoughts report a diminished sense of thought authorship. Based on its elusive neural basis, this functional neuroimaging study used a novel setup to convince healthy participants that a technical device triggers thoughts in their stream of consciousness. Self-reports indicate that participants experienced their thoughts as self-generated when they believed the (fake) device was deactivated, and attributed their thoughts externally when they believed the device was activated-an experience usually only reported by patients diagnosed with schizophrenia. Distinct activations in the medial prefrontal cortex (mPFC) were observed: ventral mPFC activation was linked to a sense of thought authorship and dorsal mPFC activation to a diminished sense of thought authorship. This functional differentiation corresponds to research on self- and other-oriented reflection processes and on patients with schizophrenia who show abnormal mPFC activation. Results thus support the notion that the mPFC might be involved in thought authorship as well as anomalous self-experiences.
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Affiliation(s)
- Leonie Klock
- Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany.,Clinic and Policlinic for Psychiatry and Psychotherapy, University Clinic Hamburg-Eppendorf, Hamburg, Germany
| | - Martin Voss
- Department of Psychiatry and Psychotherapy, Charité University Medicine and St. Hedwig-Krankenhaus, Berlin, Germany
| | - Markus Weichenberger
- Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany
| | - Norbert Kathmann
- Department of Clinical Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Simone Kühn
- Clinic and Policlinic for Psychiatry and Psychotherapy, University Clinic Hamburg-Eppendorf, Hamburg, Germany.,Lise Meitner Group for Environmental Neuroscience, Max Planck Institute for Human Development, Berlin, Germany
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6
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Larsen KM, Dzafic I, Siebner HR, Garrido MI. Alteration of functional brain architecture in 22q11.2 deletion syndrome – Insights into susceptibility for psychosis. Neuroimage 2019; 190:154-171. [DOI: 10.1016/j.neuroimage.2018.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 08/30/2018] [Accepted: 09/02/2018] [Indexed: 12/23/2022] Open
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7
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Shad MU. What do we know about insight into illness and its association with the underlying biology of schizophrenia? Schizophr Res 2018; 193:41-42. [PMID: 28864282 DOI: 10.1016/j.schres.2017.08.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/09/2017] [Accepted: 08/13/2017] [Indexed: 11/17/2022]
Affiliation(s)
- Mujeeb U Shad
- Oregon Heath & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, United States; Oregon State Hospital, 2600 Center Street NE, Salem, OR 97301, United States.
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8
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Rao N, Menon S. A heuristic model linking yoga philosophy and self-reflection to examine underlying mechanisms of add-on yoga treatment in schizophrenia. Int Rev Psychiatry 2016; 28:265-72. [PMID: 27310309 DOI: 10.1080/09540261.2016.1194259] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Preliminary evidence suggests efficacy of yoga as add-on treatment for schizophrenia, but the underlying mechanism by which yoga improves the symptoms of schizophrenia is not completely understood. Yoga improves self-reflection in healthy individuals, and self-reflection abnormalities are typically seen in schizophrenia. However, whether yoga treatment improves impairments in self-reflection typically seen in patients with schizophrenia is not examined. This paper discusses the potential mechanism of yoga in the treatment of schizophrenia and proposes a testable hypothesis for further empirical studies. It is proposed that self-reflection abnormalities in schizophrenia improve with yoga and the neurobiological changes associated with this can be examined using empirical behavioural measures and neuroimaging measures such as magnetic resonance imaging.
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Affiliation(s)
- Naren Rao
- a National Institute of Mental Health and Neurosciences , Bangalore , India
| | - Sangeetha Menon
- b National Institute of Advanced studies , Bangalore , India
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9
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Behavioral and neural correlates of self-referential processing deficits in bipolar disorder. Sci Rep 2016; 6:24075. [PMID: 27052432 PMCID: PMC4823703 DOI: 10.1038/srep24075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/18/2016] [Indexed: 11/08/2022] Open
Abstract
Self-referential processing is a core component of social cognition. However, few studies have focused on whether self-referential processing deficits present in bipolar disorder. The current study combined a high-time-resolution event-related potential (ERP) technique with the self-referential memory (SRM) task to evaluate self-referential processing in 23 bipolar patients and 27 healthy controls. All subjects showed a reliable SRM effect, but the bipolar group had poorer recognition scores for the self- and other-referential conditions. The bipolar group presented with smaller voltages in both the self- and other-referential conditions for the N1 (150-220 ms) and the P2 components (130-320 ms) but larger voltages in the positive slow wave (600-1600 ms) component. Larger P3 amplitudes were elicited in the self-referential condition compared with the other-referential condition in controls but not in bipolar patients. Additionally, non-psychotic bipolar patients had a comparative normal SRM effect which was abolished in psychotic bipolar patients; non-psychotic bipolar patients had larger amplitudes of the positive slow wave than the normal controls, whereas it was not differed between psychotic bipolar patients and the healthy subjects. The present study suggests that self- and other-referential processing is impaired in bipolar patients and the deficits may be more pronounced in psychotic bipolar patients.
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10
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Abstract
A number of recent articles, many appearing in Schizophrenia Bulletin, signal a renewed interest in phenomenological approaches to our understanding of schizophrenia. These approaches conceptualize schizophrenia as a disorder of altered self-awareness and decreased prereflective social attunement, which may manifest as an impaired understanding of self, others, and the physical world. Phenomenological approaches to psychopathology are sometimes construed as being incompatible with the reductionistic methodology of contemporary neuroscience. In this article, we re-examine findings from the phenomenological investigation of schizophrenia in light of an influential neurocomputational account of mindreading, which postulates that understanding of others is subserved by coherent internal self-models. We argue that the phenomenological approach to schizophrenia is not incompatible with a neurocomputational account of mindreading, and that the 2 approaches should instead be viewed as existing in a relationship of mutual constraint and enlightenment. Our hypothesis, while speculative, is an attempt to marry the phenomenological and neuronal realities of schizophrenia. Furthermore, it has implications for psychotherapeutic interventions and future research.
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Affiliation(s)
| | - Alvaro Barrera
- Warneford Hospital, Oxford Health NHS Foundation Trust, Oxford, UK; Department of Psychiatry, University of Oxford, Oxford, UK
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11
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Tan S, Zhao Y, Fan F, Zou Y, Jin Z, Zen Y, Zhu X, Yang F, Tan Y, Zhou D. Brain Correlates of Self-Evaluation Deficits in Schizophrenia: A Combined Functional and Structural MRI Study. PLoS One 2015; 10:e0138737. [PMID: 26406464 PMCID: PMC4583545 DOI: 10.1371/journal.pone.0138737] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/01/2015] [Indexed: 11/11/2022] Open
Abstract
Self-evaluation plays an important role in adaptive functioning and is a process that is typically impaired in patients with schizophrenia. Underlying neural mechanisms for this dysfunction may be associated with manifested psychosis. However, the brain substrates underlying this deficit are not well known. The present study used brain blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) and gray matter voxel-based morphometry to explore the functional and structural brain correlates of self-evaluation deficits in schizophrenia. Eighteen patients with schizophrenia and 17 healthy controls were recruited and asked to judge whether a set of personality-trait adjectives were appropriate for describing themselves, a familiar other, or whether the adjectives were of positive or negative valence. Patients had slower response times for negative trait attributions than controls did; responses to positive trait attributions were faster than those for negative traits among the patient group, while no differences were observed in the control group. Control subjects showed greater activation within the dorsal medial prefrontal cortex (dMPFC) and the anterior cingulate cortex (ACC) than the patient group during the self-evaluation > semantic positivity-evaluation contrast. Patients showed greater activation mainly within the posterior cingulate gyrus (PCC) as compared to controls for the other-evaluation > semantic positivity-evaluation contrast. Furthermore, gray matter volume was reduced in the MPFC, temporal lobe, cuneus, and the dorsal lateral prefrontal cortex (DLPFC) among the patient group when compared to controls. The present study adds to previous findings regarding self- and other-referential processing in schizophrenia, providing support for neurobiological models of self-reflection impairment.
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Affiliation(s)
- Shuping Tan
- Institute of Mental Health, Peking University, Beijing, 100191, China
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
| | - Yanli Zhao
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
| | - Fengmei Fan
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
| | - Yizhuang Zou
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
- * E-mail: (YZZ); (DFZ)
| | - Zhen Jin
- Magnetic Research Imaging Unit, The 306th Hospital of PLA, Beijing, 100101, China
| | - Yawei Zen
- Magnetic Research Imaging Unit, The 306th Hospital of PLA, Beijing, 100101, China
| | - Xiaolin Zhu
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
| | - Fude Yang
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
| | - Yunlong Tan
- Center of Psychiatry Research, Beijing Huilongguan Hospital, Beijing, 100096, China
| | - Dongfeng Zhou
- Institute of Mental Health, Peking University, Beijing, 100191, China
- * E-mail: (YZZ); (DFZ)
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12
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Van Hoeck N, Watson PD, Barbey AK. Cognitive neuroscience of human counterfactual reasoning. Front Hum Neurosci 2015; 9:420. [PMID: 26257633 PMCID: PMC4511878 DOI: 10.3389/fnhum.2015.00420] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 07/07/2015] [Indexed: 12/16/2022] Open
Abstract
Counterfactual reasoning is a hallmark of human thought, enabling the capacity to shift from perceiving the immediate environment to an alternative, imagined perspective. Mental representations of counterfactual possibilities (e.g., imagined past events or future outcomes not yet at hand) provide the basis for learning from past experience, enable planning and prediction, support creativity and insight, and give rise to emotions and social attributions (e.g., regret and blame). Yet remarkably little is known about the psychological and neural foundations of counterfactual reasoning. In this review, we survey recent findings from psychology and neuroscience indicating that counterfactual thought depends on an integrative network of systems for affective processing, mental simulation, and cognitive control. We review evidence to elucidate how these mechanisms are systematically altered through psychiatric illness and neurological disease. We propose that counterfactual thinking depends on the coordination of multiple information processing systems that together enable adaptive behavior and goal-directed decision making and make recommendations for the study of counterfactual inference in health, aging, and disease.
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Affiliation(s)
- Nicole Van Hoeck
- Psychology and Educational Sciences, Vrije Universiteit BrusselBrussels, Belgium
| | - Patrick D. Watson
- Decision Neuroscience Laboratory, Beckman Institute for Advanced Science and Technology, University of IllinoisUrbana, IL, USA
| | - Aron K. Barbey
- Decision Neuroscience Laboratory, Beckman Institute for Advanced Science and Technology, University of IllinoisUrbana, IL, USA
- Department of Internal Medicine, University of IllinoisChampaign, IL, USA
- Department of Psychology, University of IllinoisChampaign, IL, USA
- Department of Speech and Hearing Science, University of IllinoisChampaign, IL, USA
- Neuroscience Program, University of IllinoisChampaign, IL, USA
- Carle R. Woese Institute for Genomic Biology, University of IllinoisChampaign, IL, USA
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13
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Shad MU, Keshavan MS. Neurobiology of insight deficits in schizophrenia: An fMRI study. Schizophr Res 2015; 165:220-6. [PMID: 25957484 PMCID: PMC4457549 DOI: 10.1016/j.schres.2015.04.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 04/15/2015] [Accepted: 04/17/2015] [Indexed: 12/20/2022]
Abstract
Prior research has shown insight deficits in schizophrenia to be associated with specific neuroimaging changes (primarily structural) especially in the prefrontal sub-regions. However, little is known about the functional correlates of impaired insight. Seventeen patients with schizophrenia (mean age 40.0±10.3; M/F=14/3) underwent fMRI on a Philips 3.0 T Achieva system while performing on a self-awareness task containing self- vs. other-directed sentence stimuli. SPM5 was used to process the imaging data. Preprocessing consisted of realignment, coregistration, and normalization, and smoothing. A regression analysis was used to examine the relationship between brain activation in response to self-directed versus other-directed sentence stimuli and average scores on behavioral measures of awareness of symptoms and attribution of symptoms to the illness from Scale to Assess Unawareness of Mental Disorders. Family Wise Error correction was employed in the fMRI analysis. Average scores on awareness of symptoms (1=aware; 5=unaware) were associated with activation of multiple brain regions, including prefrontal, parietal and limbic areas as well as basal ganglia. However, average scores on correct attribution of symptoms (1=attribute; 5=misattribute) were associated with relatively more localized activation of prefrontal cortex and basal ganglia. These findings suggest that unawareness and misattribution of symptoms may have different neurobiological basis in schizophrenia. While symptom unawareness may be a function of a more complex brain network, symptom misattribution may be mediated by specific brain regions.
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14
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Zhao Y, Zhang D, Tan S, Song C, Cui J, Fan F, Zhu X, Zou Y, Luo Y. Neural correlates of the abolished self-referential memory effect in schizophrenia. Psychol Med 2014; 44:477-487. [PMID: 23721746 DOI: 10.1017/s0033291713001177] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The self-referential memory (SRM) effect refers to the phenomenon that stimuli processed with reference to the self are better remembered than those referenced to others. Studies have shown that schizophrenia patients do not have this memorial advantage for self-referenced information. The current study investigated the electrophysiological mechanism of the abolished SRM effect in schizophrenia. METHOD Twenty schizophrenia patients and 22 controls were recruited to complete an SRM task. We used a high-time resolution event-related potential (ERP) technique to analyze the electrophysiological differences between patients and controls during self- and other-reflection processing. RESULTS Behavior data indicated that healthy controls had a typical SRM bias that was absent in the schizophrenia patients. ERP comparison between groups showed that the schizophrenia patients presented smaller voltages in both self- and other-reflection conditions in the 160-260 ms (P2 component) and 800-1200 ms (positive slow wave) time windows over the pre/frontal cortex. Furthermore, the N2 amplitudes (270-380 ms) differed between self- and other-reflection conditions in patients but not in normal controls. More importantly, we found that the P3 amplitudes in the parietal cortex correlated significantly with the SRM bias score in the patients (r = -0.688). CONCLUSIONS These results provide comprehensive and direct electrophysiological evidence for self- and other-reflective dysfunction in schizophrenia patients and contribute to our understanding of the underlying neural substrates of the abolished SRM effect in schizophrenia.
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Affiliation(s)
- Y Zhao
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - D Zhang
- Institute of Affective and Social Neuroscience, Shenzhen University, China
| | - S Tan
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - C Song
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - J Cui
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - F Fan
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - X Zhu
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - Y Zou
- Center for Psychiatric Research, Beijing Huilongguan Hospital, China
| | - Y Luo
- Institute of Affective and Social Neuroscience, Shenzhen University, China
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15
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Shad MU, Keshavan MS, Steinberg JL, Mihalakos P, Thomas BP, Motes MA, Soares JC, Tamminga CA. Neurobiology of self-awareness in schizophrenia: an fMRI study. Schizophr Res 2012; 138:113-9. [PMID: 22480958 PMCID: PMC3372627 DOI: 10.1016/j.schres.2012.03.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 03/06/2012] [Accepted: 03/07/2012] [Indexed: 11/16/2022]
Abstract
Self-awareness (SA) is one of the core domains of higher cortical functions and is frequently compromised in schizophrenia. Deficits in SA have been associated with functional and psychosocial impairment in this patient population. However, despite its clinical significance, only a few studies have examined the neural substrates of self-referential processing in schizophrenia. The aim of this study was to assess self-awareness in schizophrenia using a functional magnetic resonance imaging (fMRI) paradigm designed to elicit judgments of self-reference in a simulated social context. While scanned, volunteers looked at visually-displayed sentences that had the volunteer's own first name (self-directed sentence-stimulus) or an unknown other person's first name (other-directed sentence stimulus) as the grammatical subject of the sentence. The volunteers were asked to discern whether each sentence-stimulus was about the volunteer personally (during a self-referential cue epoch) or asked whether each statement was about someone else (during an other-referential cue epoch). We predicted that individuals with schizophrenia would demonstrate altered functional activation to self- and other-directed sentence-stimuli as compared to controls. Fifteen controls and seventeen schizophrenia volunteers completed clinical assessments and SA fMRI task on a 3T Philips 3.0 T Achieva system. The results showed significantly greater activation in schizophrenia compared to controls for cortical midline structures in response to self- vs. other-directed sentence-stimuli. These findings support results from earlier studies and demonstrate selective alteration in the activation of cortical midline structures associated with evaluations of self-reference in schizophrenia as compared to controls.
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Affiliation(s)
- Mujeeb U. Shad
- The University of Texas Health Science Center, Houston, TX
| | | | | | | | | | | | - Jair C. Soares
- The University of Texas Health Science Center, Houston, TX
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