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Impairment of semantic composition in schizophrenia: An ERP study with lexical stimuli. Neuropsychologia 2022; 171:108241. [DOI: 10.1016/j.neuropsychologia.2022.108241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 11/24/2022]
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Bohec AL, de Loye C, Baltazar M, Blanchet A, Rey R, Kostova M. N400 Peculiarities During Intentional Inferences Production in Subjects With Schizotypal Traits. J PSYCHOPHYSIOL 2022. [DOI: 10.1027/0269-8803/a000292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. A deficit in context processing may underlie theory of mind (ToM) difficulties in schizophrenia, although few studies to date have explored the impact of contextual processing on ToM performances within the same task. We used electroencephalography to investigate the production of intentional inferences from highly versus weakly structured sentences in healthy participants with schizotypal traits. Thirty-four participants were divided into two groups according to their scores on the Schizotypal Personality Questionnaire (SPQ). The participants listened to stories that required a degree of understanding in order to produce an inference about the main character’s intention. Each story was followed by a target word that could either be highly predictable (HP), weakly predictable (WP), or incompatible with the context. The results indicate that the N400 component for WP targets was stronger in the high-SPQ group. This increase correlated with the negative dimension of schizotypy. This may reflect difficulties with generating intentional inferences when the context is insufficiently structured for high schizotypy participants.
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Affiliation(s)
- Anne-Lise Bohec
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Psychiatric Disorders: From Resistance to Response Team, Lyon, France
- University Lyon 1, Villeurbanne, France
- Schizophrenia Expert Centre, Le Vinatier Hospital, Bron, France
- Fondation FondaMental, Créteil, France
- Laboratoire de Psychopathologie et Neuropsychologie (EA2027) Université Paris 8, Saint-Denis, France
| | - Claire de Loye
- Laboratoire de Psychopathologie et Neuropsychologie (EA2027) Université Paris 8, Saint-Denis, France
| | - Matias Baltazar
- Centre Hospitalier Le Vinatier, Pôle Pédopsychiatrie, Bron, France
| | - Alain Blanchet
- Laboratoire de Psychopathologie et Neuropsychologie (EA2027) Université Paris 8, Saint-Denis, France
| | - Romain Rey
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Psychiatric Disorders: From Resistance to Response Team, Lyon, France
- University Lyon 1, Villeurbanne, France
- Schizophrenia Expert Centre, Le Vinatier Hospital, Bron, France
- Fondation FondaMental, Créteil, France
| | - Milena Kostova
- Laboratoire Paragraphe (UR 349) Université Paris 8, Saint-Denis, France
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Lepock JR, Ahmed S, Mizrahi R, Gerritsen CJ, Maheandiran M, Bagby RM, Korostil M, Kiang M. N400 event-related brain potential as an index of real-world and neurocognitive function in patients at clinical high risk for schizophrenia. Early Interv Psychiatry 2021; 15:68-75. [PMID: 31883227 DOI: 10.1111/eip.12911] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/27/2019] [Accepted: 12/14/2019] [Indexed: 11/28/2022]
Abstract
AIM The N400 event-related potential is a neurophysiological index of cognitive processing of real-world knowledge. In healthy populations, N400 amplitude is smaller in response to stimuli that are more related to preceding context. This 'N400 semantic priming effect' is thought to reflect activation of contextually related information in semantic memory (SM). N400 semantic priming deficits have been found in schizophrenia, and in patients at clinical high risk (CHR) for this disorder. Because this abnormality in processing relationships between meaningful stimuli could affect ability to navigate everyday situations, we hypothesized it would be associated with real-world functional impairment in CHR patients. Second, we hypothesized it would correlate with global neurocognitive impairment in this group. METHODS We measured N400 semantic priming in 35 CHR patients who viewed prime words each followed by a related or unrelated target word, at stimulus-onset asynchrony (SOA) of 300 or 750 ms. We measured academic/occupational and social function with the global function (GF): Role and Social scales, and cognitive function with the MATRICS Consensus Cognitive Battery (MCCB). RESULTS Decreased N400 semantic priming at the 300-ms SOA correlated with lower GF:Role scores. Decreased N400 semantic priming at the 750-ms SOA correlated with lower MCCB composite scores. CONCLUSIONS Deficits in activating contextually related concepts in SM over short time intervals may contribute to functional impairment in CHR patients. Furthermore, N400 priming deficits over longer intervals may be a biomarker of global cognitive dysfunction in this population. Longitudinal studies are needed to determine whether these deficits are associated with schizophrenia risk within this population.
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Affiliation(s)
- Jennifer R Lepock
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Cory J Gerritsen
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | | | - R Michael Bagby
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michele Korostil
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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Riedl L, Nagels A, Sammer G, Straube B. A Multimodal Speech-Gesture Training Intervention for Patients With Schizophrenia and Its Neural Underpinnings - the Study Protocol of a Randomized Controlled Pilot Trial. Front Psychiatry 2020; 11:110. [PMID: 32210849 PMCID: PMC7068208 DOI: 10.3389/fpsyt.2020.00110] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 02/07/2020] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Dysfunctional social communication is one of the most stable characteristics in patients with schizophrenia that also affects quality of life. Interpreting abstract speech and integrating nonverbal modalities is particularly affected. Considering the impact of communication on social life but failure to treat communication dysfunctions with usual treatment, we will investigate the possibility to improve verbal and non-verbal communication in schizophrenia by applying a multimodal speech-gesture training (MSG training). Here we describe the newly developed MSG training program and the study design for the first clinical investigation. The intervention contains perceptive rating (match/mismatch of sentence and gesture) and memory tasks (n-back tasks), imitation and productive tasks (e.g., SG fluency-similar to verbal fluency where words are accompanied by gesture). In addition, we offer information about gesture as meta-learning element as well as homework for reasons of transfer to everyday life as part of every session. In the MSG training intervention, we offer eight sessions (60 min each) of training. The first pilot study is currently conducted as a single-center, randomized controlled trial of speech-gesture intervention versus wait-list control with a follow-up. Outcomes are measured through pre-post-fMRI and standardized psychological questionnaires comparing two subject groups (30 patients with schizophrenia and 30 healthy controls). Patients and healthy controls are randomized in two intervention groups (with 20 being in the wait-training group and 10 in the training-follow-up group). With our study design we will be able to demonstrate the beneficial effect of the MSG training intervention on behavioral and neural levels. CLINICAL TRIAL REGISTRATION DRKS.de, identifier DRKS00015118.
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Affiliation(s)
- Lydia Riedl
- Translational Neuroimaging Lab, Department of Psychiatry and Psychotherapy, Philipps-University Marburg, Marburg, Germany
| | - Arne Nagels
- Department of English and Linguistics, Johannes-Gutenberg-University, Mainz, Germany
| | - Gebhard Sammer
- Department of Psychiatry and Psychotherapy, Justus-Liebig-University, Gießen, Germany
| | - Benjamin Straube
- Translational Neuroimaging Lab, Department of Psychiatry and Psychotherapy, Philipps-University Marburg, Marburg, Germany
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The N400 event-related brain potential response: A window on deficits in predicting meaning in schizophrenia. Int J Psychophysiol 2019; 145:65-69. [DOI: 10.1016/j.ijpsycho.2019.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 04/08/2019] [Accepted: 04/16/2019] [Indexed: 11/22/2022]
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An Event Related Potentials Study of Semantic Coherence Effect during Episodic Encoding in Schizophrenia Patients. SCHIZOPHRENIA RESEARCH AND TREATMENT 2018. [PMID: 29535872 PMCID: PMC5817848 DOI: 10.1155/2018/8501973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The objective of this electrophysiological study was to investigate the processing of semantic coherence during encoding in relation to episodic memory processes promoted at test, in schizophrenia patients, by using the N400 paradigm. Eighteen schizophrenia patients and 15 healthy participants undertook a recognition memory task. The stimuli consisted of pairs of words either semantically related or unrelated to a given category name (context). During encoding, both groups exhibited an N400 external semantic coherence effect. Healthy controls also showed an N400 internal semantic coherence effect, but this effect was not present in patients. At test, related stimuli were accompanied by an FN400 old/new effect in both groups and by a parietal old/new effect in the control group alone. In the patient group, external semantic coherence effect was associated with FN400, while, in the control group, it was correlated to the parietal old/new effect. Our results indicate that schizophrenia patients can process the contextual information at encoding to enhance familiarity process for related stimuli at test. Therefore, cognitive rehabilitation therapies targeting the implementation of semantic encoding strategies can mobilize familiarity which in turn can overcome the recollection deficit, promoting successful episodic memory performance in schizophrenia patients.
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Impaired context processing during irony comprehension in schizotypy: An ERPs study. Int J Psychophysiol 2016; 105:17-25. [DOI: 10.1016/j.ijpsycho.2016.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/15/2016] [Accepted: 04/22/2016] [Indexed: 02/06/2023]
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Battal Merlet L, Morel S, Blanchet A, Lockman H, Kostova M. Effect of semantic coherence on episodic memory processes in schizophrenia. Psychiatry Res 2014; 220:752-9. [PMID: 25240943 DOI: 10.1016/j.psychres.2014.08.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 07/15/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
Abstract
Schizophrenia is associated with severe episodic retrieval impairment. The aim of this study was to investigate the possibility that schizophrenia patients could improve their familiarity and/or recollection processes by manipulating the semantic coherence of to-be-learned stimuli and using deep encoding. Twelve schizophrenia patients and 12 healthy controls of comparable age, gender, and educational level undertook an associative recognition memory task. The stimuli consisted of pairs of words that were either related or unrelated to a given semantic category. The process dissociation procedure was used to calculate the estimates of familiarity and recollection processes. Both groups showed enhanced memory performances for semantically related words. However, in healthy controls, semantic relatedness led to enhanced recollection, while in schizophrenia patients, it induced enhanced familiarity. The familiarity estimates for related words were comparable in both groups, indicating that familiarity could be used as a compensatory mechanism in schizophrenia patients.
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Affiliation(s)
- Lâle Battal Merlet
- Université Paris 8, Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, 2 rue de la Liberté, 93526 Saint-Denis Cedex, France; University Malaya, Psychological Medicine Department, Kuala Lumpur, Malaysia.
| | - Shasha Morel
- Université Paris 8, Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, 2 rue de la Liberté, 93526 Saint-Denis Cedex, France; Université François-Rabelais, UMR-CNRS 7295, CeRCA, Tours, France
| | - Alain Blanchet
- Université Paris 8, Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, 2 rue de la Liberté, 93526 Saint-Denis Cedex, France
| | - Hazlin Lockman
- University Malaya, Psychological Medicine Department, Kuala Lumpur, Malaysia
| | - Milena Kostova
- Université Paris 8, Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, 2 rue de la Liberté, 93526 Saint-Denis Cedex, France
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Test-retest reliability of N400 event-related brain potential measures in a word-pair semantic priming paradigm in patients with schizophrenia. Schizophr Res 2014; 158:195-203. [PMID: 25015029 DOI: 10.1016/j.schres.2014.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 11/23/2022]
Abstract
The N400 event-related brain potential (ERP), a negative voltage deflection occurring approximately 400ms after onset of any meaningful stimulus, is reduced in amplitude when the stimulus is preceded by related context. Previous work has found this N400 semantic priming effect to be decreased in schizophrenia, suggesting impairment in using meaningful context to activate related concepts in semantic memory. Thus, N400 amplitude may be a useful biomarker of abnormal semantic processing and its response to treatment in schizophrenia. To help assess the validity of N400 amplitude as a longitudinal measure in schizophrenia, we evaluated its test-retest reliability. ERPs were recorded in sixteen schizophrenia patients who viewed prime words, each followed at 300- or 750-ms stimulus-onset asynchrony (SOA) by a target that was either a related or unrelated word, or nonword. Participants' task was to indicate whether or not the target was a real word. They were retested on the same procedure one week later. Test-retest reliability was assessed by calculating Pearson's r and intraclass correlation coefficients (ICCs) across timepoints for N400 amplitudes for related and unrelated targets, at each SOA. Consistent with previous results, there were no significant differences between patients' N400 amplitudes for related and unrelated targets, at any SOA/timepoint combination. Pearson's r and ICCs for N400 amplitudes at Fz across timepoints were significant for both target types at each SOA (ranges: r 0.52-0.64, ICC 0.52-0.63; all p<.04). The results suggest potential utility of N400 amplitude as a longitudinal neurophysiological biomarker of semantic processing abnormalities in schizophrenia.
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Kostova M, Bohec AL, Blanchet A. Event-related brain potential study of expectancy and semantic matching in schizotypy. Int J Psychophysiol 2014; 92:67-73. [PMID: 24607603 DOI: 10.1016/j.ijpsycho.2014.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/14/2014] [Accepted: 02/25/2014] [Indexed: 11/30/2022]
Abstract
Priming studies have revealed semantic processing abnormalities in subjects that display high schizotypal traits. The objective of the present study was to further elucidate the contribution of predictive (expectancy) and integrative (semantic matching) context processing to the semantic deficit described in schizotypy. Thirty-six participants were assigned into high or low schizotypy groups according to their score on the Schizotypal Personality Questionnaire (SPQ), and event-related brain potentials were recorded while these individuals performed semantic judgments based on asymmetrically associated word pairs. Viewed in one direction (forward), the target was highly predictable from the prime, whereas in the backward direction, the prime-to-target association was weak. It was assumed that the forward condition would be dependent on expectancy generation, while the backward condition would rely on semantic matching. In the low-SPQ group, forward and backward related words evoked a reduced (less negative) N400 amplitude compared to unrelated words, resulting in a significant forward and backward N400 priming effect, respectively. By contrast, only forward related words were facilitated in the high-SPQ group, resulting in significant forward priming and a lack of backward priming. Furthermore, the N400 amplitude for forward related words was less negative within the high-SPQ group in comparison to the low-SPQ group, which indicated easier semantic access to predictable words for high-SPQ individuals. Therefore, schizotypy may be associated with an imbalance in the use of predictive and integrative context processing strategies, namely preserved, if not over allocated, expectancy generation along with altered integration of unpredictable words due to semantic matching deficit.
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Affiliation(s)
- Milena Kostova
- Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, Université Paris 8, Saint-Denis, France.
| | - Anne-Lise Bohec
- Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, Université Paris 8, Saint-Denis, France
| | - Alain Blanchet
- Laboratoire de Psychopathologie et Neuropsychologie, EA 2027, Université Paris 8, Saint-Denis, France
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Kiang M, Christensen BK, Zipursky RB. Event-related brain potential study of semantic priming in unaffected first-degree relatives of schizophrenia patients. Schizophr Res 2014; 153:78-86. [PMID: 24451397 DOI: 10.1016/j.schres.2014.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 12/25/2013] [Accepted: 01/02/2014] [Indexed: 10/25/2022]
Abstract
Schizophrenia is associated with abnormalities in using meaningful stimuli to activate or prime related concepts in semantic long-term memory. A neurophysiological index of this activation is the N400, an event-related brain potential (ERP) waveform elicited by meaningful stimuli, which is normally reduced (made less negative) by relatedness between the eliciting stimulus and preceding ones (N400 semantic priming). Schizophrenia patients exhibit N400 semantic priming deficits, suggesting impairment in using meaningful context to activate related concepts. To address whether this abnormality is a trait-like marker of liability to schizophrenia or, alternatively, a biomarker of the illness itself, we tested for its presence in schizophrenia patients' unaffected biological relatives. We recorded ERPs from 12 unaffected first-degree relatives of schizophrenia patients, 12 schizophrenia patients, and 12 normal control participants (NCPs) who viewed prime words each followed at 300- or 750-ms stimulus-onset asynchrony (SOA) by an unrelated or related target word, or a nonword, in a lexical-decision task. As expected, across SOAs, NCPs exhibited smaller (less negative) N400 amplitudes for related versus unrelated targets. The same pattern held in relatives, whose N400 amplitudes for related and unrelated targets did not differ from NCPs'. In contrast, consistent with previous results, schizophrenia patients exhibited larger N400 amplitudes than NCPs (and relatives) for related targets, such that patients' N400 amplitudes for related and unrelated targets did not differ. N400 amplitudes for unrelated targets did not differ between the three groups. Thus, N400 semantic priming deficits in a visual word-pair paradigm may be an illness biomarker for schizophrenia.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; St. Joseph's Healthcare, Hamilton, Ontario, Canada.
| | - Bruce K Christensen
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Robert B Zipursky
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada; St. Joseph's Healthcare, Hamilton, Ontario, Canada
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de Loye C, Beaucousin V, Bohec AL, Blanchet A, Kostova M. An event-related potential study of predictive and integrative semantic context processing in subjects with schizotypal traits. Psychophysiology 2013; 50:1109-19. [DOI: 10.1111/psyp.12124] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Claire de Loye
- Laboratoire de Psychopathologie et Neuropsychologie (EA 2027); Université Paris 8; Saint-Denis France
| | - Virginie Beaucousin
- Laboratoire de Psychopathologie et Neuropsychologie (EA 2027); Université Paris 8; Saint-Denis France
| | - Anne-Lise Bohec
- Laboratoire de Psychopathologie et Neuropsychologie (EA 2027); Université Paris 8; Saint-Denis France
| | - Alain Blanchet
- Laboratoire de Psychopathologie et Neuropsychologie (EA 2027); Université Paris 8; Saint-Denis France
| | - Milena Kostova
- Laboratoire de Psychopathologie et Neuropsychologie (EA 2027); Université Paris 8; Saint-Denis France
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Électrophysiologie et vulnérabilité schizophrénique : la composante N400 comme endophénotype candidat ? Neurophysiol Clin 2013; 43:81-94. [DOI: 10.1016/j.neucli.2013.01.119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 11/20/2022] Open
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Abstract
PURPOSE OF REVIEW The purpose of this article is to review major findings in event related potential (ERP) research in schizophrenia patients, specifically focusing on the N400 component. RECENT FINDINGS Patients with chronic schizophrenia have difficulty using 'context' (understanding the meaning of the word relative to the sentence) in sentence processing studies and often show differences from control populations in language experiments using word priming. Both of these observations are associated with an abnormal N400 ERP component when compared with nonpsychotic individuals. Many studies of language function rely on priming paradigms that use pairs of words such that the first word in a pair is a 'prime' and a second word in a pair is a 'target', separated from the prime by a period of time known as the Stimulus Onset Asynchrony (SOA). If the SOA is short (i.e., below 400 ms) then it is believed that a priming study examines primarily processes of initial activation within semantic networks; if it is long (i.e., more than 400 ms) then it is believed that a priming study examines primarily processes of context use, generating predictions and matching these predictions against upcoming semantic information. Priming paradigms that use long SOAs are consistently associated with a more negative N400 (hence lack of priming) in schizophrenia, whereas priming paradigms using a short SOA produce either a normal N400 priming response or hyperpriming as shown by a reduced N400 and related to a hypothesized too rapid automatic spread of activation within the semantic memory pathway. Apparent differences among reported study results are likely due to paradigm differences that tap into different aspects of language processing. Although the presence of both hyperactivation within semantic networks and difficulties with the use of context is well known in schizophrenia, it is unclear whether these abnormalities are also present prior to illness onset in people who are at risk for development of schizophrenia or even present at the onset of illness. SUMMARY In order to clarify the findings reviewed here, future studies will be needed that focus on examining the N400 response in young people at high risk for developing the illness using multiple paradigms that probe different aspects of language function.
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Kiang M, Christensen BK, Streiner DL, Roy C, Patriciu I, Zipursky RB. Association of abnormal semantic processing with delusion-like ideation in frequent cannabis users: an electrophysiological study. Psychopharmacology (Berl) 2013; 225:95-104. [PMID: 22782461 PMCID: PMC5045303 DOI: 10.1007/s00213-012-2800-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 06/27/2012] [Indexed: 01/23/2023]
Abstract
RATIONALE Frequent cannabis use is a risk marker for schizophrenia and delusions, but the neurocognitive mechanisms of this relationship remain unclear. OBJECTIVES We sought evidence that cannabis users have deficits in processing relationships between meaningful stimuli, similar to abnormalities reported in schizophrenia, and that these deficits are associated with delusion-like ideation. We used the N400 event-related brain potential (ERP) waveform as a neurophysiological probe of activation of concepts in semantic memory. We hypothesized that cannabis users would exhibit larger (more negative) than normal N400 amplitudes in response to stimuli meaningfully related to a preceding prime-reflecting deficient activation of concepts related to the prime. We further hypothesized that the magnitude of this abnormality would correlate with severity of delusion-like ideation. METHODS We recorded ERPs in 24 frequent cannabis users and 24 non-using comparison participants who viewed prime words followed by targets which were either words related or unrelated to the prime or pronounceable nonwords. The participants' task was to indicate whether the target was a word. Delusion-like ideation was measured via the Schizotypal Personality Questionnaire. RESULTS Contrary to our hypothesis, cannabis users exhibited smaller than normal N400s to both related and unrelated targets. These abnormalities correlated with delusion-like ideation in cannabis users only. CONCLUSIONS The results are consistent with a generalized abnormality of activation within semantic memory neural networks in cannabis users. Further research is needed to investigate whether such an abnormality plays a role in the development of delusion-like ideation in cannabis users.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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Wang K, Cheung EFC, Gong QY, Chan RCK. Semantic processing disturbance in patients with schizophrenia: a meta-analysis of the N400 component. PLoS One 2011; 6:e25435. [PMID: 22022395 PMCID: PMC3192062 DOI: 10.1371/journal.pone.0025435] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 09/05/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Theoretically semantic processing can be separated into early automatic semantic activation and late contextualization. Semantic processing deficits have been suggested in patients with schizophrenia, however it is not clear which stage of semantic processing is impaired. We attempted to clarify this issue by conducting a meta-analysis of the N400 component. METHODS Twenty-one studies met the inclusion criteria for the meta-analysis procedure. The Comprehensive Meta-Analysis software package was used to compute pooled effect sizes and homogeneity. RESULTS Studies favoring early automatic activation produced a significant effect size of -0.41 for the N400 effect. Studies favoring late contextualization generated a significant effect size of -0.36 for the N400 effect, a significant effect size of -0.52 for N400 for congruent/related target words, and a significant effect size of 0.82 for the N400 peak latency. CONCLUSION These findings suggest the automatic spreading activation process in patients with schizophrenia is very similar for closely related concepts and weakly or remotely related concepts, while late contextualization may be associated with impairments in processing semantically congruent context accompanied by slow processing speed.
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Affiliation(s)
- Kui Wang
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Eric F. C. Cheung
- Castle Peak Hospital, Hong Kong Special Administrative Region, China
| | - Qi-yong Gong
- Huaxi MR Research Centre, Department of Radiology, West China Hospital/West China School of Medicine, Sichuan University, Chengdu, China
| | - Raymond C. K. Chan
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Vistoli D, Passerieux C, Houze B, Hardy-Baylé MC, Brunet-Gouet E. Neural basis of semantic priming in schizophrenia during a lexical decision task: a magneto-encephalography study. Schizophr Res 2011; 130:114-22. [PMID: 21684123 DOI: 10.1016/j.schres.2011.05.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 05/19/2011] [Accepted: 05/22/2011] [Indexed: 10/18/2022]
Abstract
Numerous behavioral and electrophysiological studies have provided evidence of abnormal semantic processing in schizophrenia. However, the neural basis of these deficits is poorly understood. We investigated magnetic cortical responses elicited by a word-pair lexical decision task in 20 patients with schizophrenia and 12 healthy control subjects. The task involved presentation of a prime word (200 ms), followed by a blank (250 ms), and then a target stimulus (1200 ms); the subject had to decide whether the target was a real word or not. During this task, bilateral temporal and left prefrontal activations were observed in both groups. However, in contrast to controls, patients with schizophrenia did not show increased activation in the left temporal and anterior cingulate cortices between 200 and 450 ms in response to semantic incongruity. These results suggested that schizophrenia was associated with a functional disturbance in some semantic regions that gave rise to the N400 component. Moreover, a significant modulation in the right temporal cortex was observed in patients, but not in controls. This suggested the existence of alternative processes in patients because both groups showed similar behavioral priming. Finally, we elucidated some functional abnormalities in the semantic network during prime word processing in patients, indicated by prolonged activation compared to healthy controls. Thus, in addition to context integration impairment, abnormal activations during the prime word provided new evidence of context processing deficits in schizophrenia.
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Affiliation(s)
- Damien Vistoli
- EA 4047, Université de Versailles Saint-Quentin, Service de Psychiatrie Adulte, Centre Hospitalier de Versailles, Fondation FondaMental, 177 route de Versailles, 78150 Le Chesnay, France.
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Kostova M, de Loye C, Blanchet A. Left but not right hemisphere semantic processing abnormalities in language comprehension in subjects with schizotypy traits. Psychiatry Res 2011; 185:84-91. [PMID: 20627324 DOI: 10.1016/j.psychres.2010.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 04/30/2010] [Accepted: 05/05/2010] [Indexed: 11/24/2022]
Abstract
Thought and language disorders in schizophrenia and schizotypy are thought to result from hemispheric dysfunction during semantic processing. Left hemisphere (LH) abnormalities are well established, but little is known about right hemisphere (RH) semantic processes. We explored hemispheric processing in 50 healthy volunteers assigned to high (h-SZT) or low schizotypy (l-SZT) group using the Schizotypal Personality Questionnaire (SPQ). Subjects were asked to make semantic judgments on sentence pair ending with a target that was either expected word (EW) or an unexpected word from the same (related violation, RV) or a different category (unrelated violation, URV). Targets were presented in a dichotic manner to the left or right ear. Analyses of reaction times in the l-SZT group showed semantic compatibility effect (URV-EW) in the LH and semantic memory activation effect (RV-URV) as well as semantic compatibility effect in the RH. The h-SZT group showed semantic memory activation but no semantic compatibility effect in the LH, the RH pattern resembling that of the l-SZT group. The magnitude of the LH semantic compatibility effect was inversely correlated with SPQ total scores and SPQ Cognitive-perceptual factor. Thus, RH semantic processes are effective and there is a deficit in LH focused activation in schizotypy.
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Affiliation(s)
- Milena Kostova
- Laboratoire de Psychopathologie et Neuropsychologie (EA 2027), Université Paris 8, Saint-Denis, France.
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N400 deficits from semantic matching of pictures in probands and first-degree relatives from multiplex schizophrenia families. Brain Cogn 2009; 70:221-30. [PMID: 19307049 DOI: 10.1016/j.bandc.2009.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 02/01/2009] [Accepted: 02/03/2009] [Indexed: 11/23/2022]
Abstract
Endophenotypes is one emerging strategy in schizophrenia research that is being used to identify the functional importance of genetically transmitted, brain-based deficits present in this disease. Currently, event-related potentials (ERPs) are timely used in this search. Several ERPs, including N400, present deficits in relation to schizophrenia. In order to assess the genetic liability of N400 as a possible endophenotype, a picture semantic matching task (congruent and incongruent pairs of pictures) was performed by 21 unaffected first-degree relatives of patients with schizophrenia, 21 DSM-IV diagnosed schizophrenia probands, and 21 control subjects, matched by age, gender and educational level. Probands and relatives were selected form Multiplex schizophrenia families. Significantly reduced N400 amplitude for congruent categories in N400 was found in probands and relatives in relation to controls. The latency onset and the maximum peak latency of N400 were delayed in both, relatives and probands groups compared to control. The voltage maps of incongruous-minus-congruous difference indicate a more reduced right restricted negativity in probands and relatives, when compared to a widely extended bilateral negativity in controls. No general differences were found between patients and relatives. These results demonstrate an electrophysiological deficit in semantic match processing in clinically unaffected first-degree relatives of patients with schizophrenia, suggesting a possible use of this marker as endophenotype.
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Daltrozzo J, Wioland N, Kotchoubey B. Sex differences in two event-related potentials components related to semantic priming. ARCHIVES OF SEXUAL BEHAVIOR 2007; 36:555-68. [PMID: 17334908 DOI: 10.1007/s10508-006-9161-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 06/12/2006] [Accepted: 11/02/2006] [Indexed: 05/14/2023]
Abstract
Although sex differences in language processing are well documented in behavioral studies, only a few electrophysiological studies have explored this topic. We analyzed sex differences in two language-related components of event-related potentials (ERPs): the N400 and the Late Positive Complex (LPC). Ten men and 10 women, matched by age and handedness, participated in the study. Two semantic priming paradigms were presented: word pairs (60 congruent and 60 incongruent) and sentences (50 with congruent and 50 with incongruent ending words). In addition, the effect of context was investigated by a comparison between ERP effects obtained in single word priming and sentential priming. The N400 effect was earlier and larger in women, and the LPC effect was larger in men. Furthermore, the LPC effect in men, but not in women, was much larger with sentence priming than with word priming, suggesting that the LPC effect may be more dependent on context in men than in women. The opposite sex difference on the two ERP components indicates different underlying mechanisms. While the LPC effect is thought to be generated by purely explicit mechanisms, such as postlexical integrative processes, the N400 effect may be also governed by prelexical implicit and explicit mechanisms. Our results were consistent with the notion of more automated processing of language in women than in men.
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Affiliation(s)
- Jérôme Daltrozzo
- Department of Neurology, University Hospital of Strasbourg, Strasbourg, France.
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Kiang M, Kutas M, Light GA, Braff DL. Electrophysiological insights into conceptual disorganization in schizophrenia. Schizophr Res 2007; 92:225-36. [PMID: 17383161 PMCID: PMC3974604 DOI: 10.1016/j.schres.2007.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 01/31/2007] [Accepted: 02/02/2007] [Indexed: 11/21/2022]
Abstract
Disorganized speech, or thought disorder, in schizophrenia may reflect abnormal processing of meaningful concepts. To examine whether schizophrenia involves abnormalities in how a meaningful context influences processing of concepts strongly, weakly, or not related to it, we used the N400, an event-related brain potential (ERP) index of semantic relatedness. ERPs were recorded from schizophrenia patients (n=18) and normal controls (n=18) while they viewed category definitions (e.g., a type of fruit), each followed by a target word that was either a high-typicality category exemplar (apple), low-typicality exemplar (cherry), or non-exemplar (clamp). Participants' task was to indicate via button-press whether or not the target belonged to the category. In both patients and controls, N400 amplitude was largest (most negative) for non-exemplars, intermediate for low-typicality exemplars, and smallest (least negative) for high-typicality exemplars. Compared to controls, patients showed a trend toward reduced N400 amplitude differences between non-exemplars and low-typicality exemplars. Most importantly, within patients, reduced N400 amplitude differences between high- and low-typicality exemplars were correlated with psychotic symptoms. This association of an N400 index of semantic processing with psychotic symptoms suggests that psychosis in schizophrenia may be associated with greater similarity in how concepts strongly and weakly meaningfully related to their context are processed.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California-San Diego, 9500 Gilman Dr., Mail Code 0515, La Jolla, CA 92093-0515, USA.
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22
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Debruille JB, Kumar N, Saheb D, Chintoh A, Gharghi D, Lionnet C, King S. Delusions and processing of discrepant information: an event-related brain potential study. Schizophr Res 2007; 89:261-77. [PMID: 16945505 DOI: 10.1016/j.schres.2006.07.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 07/15/2006] [Accepted: 07/19/2006] [Indexed: 10/24/2022]
Abstract
One possible explanation for why delusions persist despite the awareness of contradictory information is that the new information fails to be integrated. Interestingly, the amplitude of the N400 event-related brain potential (ERP) has been proposed as an index of the integration of information that is discrepant with expectancies whatever the task in which the potential is found. Thus, delusions may persist because of a deficit in integration as indexed by the N400. To test this hypothesis, ERPs were recorded in 35 schizophrenia patients (mean age=30.5+/-5.6 years) and 26 normal controls during a task in which they either had to decide whether or not each target word could be integrated into the category "animal", or had no decision to make, according to the prompt "animal?" or the prompt "inaction". In these conditions, the amplitudes of the N400s to target words that were discrepant with the category were found to be negatively correlated with delusion severity. The patient group was then dichotomized according to a median split of delusion severity, excluding the 5 patients with delusion scores at the median. Mean age, sex ratio, and severity of conceptual disorganization and hallucinations of the two subgroups differed. Controlling for these 4 covariates, the N400s for discrepant targets were found smaller in the 14 More-Delusional patients than in the 16 Less-Delusional patients. These results support the hypothesis that delusions are associated with smaller N400s in patients. Further studies should thus be done to test whether a deficit of N400 processes could have a causal role in the persistence of delusions.
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Affiliation(s)
- J Bruno Debruille
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
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Kircher TTJ, Leube DT, Erb M, Grodd W, Rapp AM. Neural correlates of metaphor processing in schizophrenia. Neuroimage 2006; 34:281-9. [PMID: 17081771 DOI: 10.1016/j.neuroimage.2006.08.044] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 08/19/2006] [Accepted: 08/29/2006] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE A main feature of schizophrenic thought and language disturbance is concretism, the inability to understand the figurative meaning of proverbs and metaphors. Although this is routinely tested during clinical interview, its neural basis is unknown. METHOD We investigated processing of metaphoric sentences with functional magnetic resonance imaging (fMRI) in 12 patients with schizophrenia and 12 control subjects. Stimuli consisted of 60 novel short sentences with either metaphoric or literal meaning presented visually, intersparsed by a low level baseline (grey background). Subjects read these sentences silently and judged by button press whether they had a positive or negative connotation. RESULTS Reading metaphors in contrast to literal sentences revealed signal changes in the left inferior frontal gyrus in the control subjects (BA 45/47) and an area 3 cm dorsal to that in the patients (BA 45). Only activation in this area was negatively correlated with the severity of concretism rated with the PANSS. Comparison between groups for the contrast metaphors vs. low level baseline revealed stronger signal changes in the control group in the right superior/middle temporal gyrus (BA 39) and the left inferior frontal gyrus (BA 45) in the patients. CONCLUSIONS The results in the control subjects are in line with studies showing an involvement of the left inferior frontal and right lateral temporal cortex during context processing. Failure to recruit these areas in the patients may underlie schizophrenic concretism.
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Affiliation(s)
- Tilo T J Kircher
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Pauwelsstr. 30, D-52074 Aachen, Germany.
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Sarfati Y. Fonctions cognitives et rémission. Encephale 2005; 31 Pt 2:S21-3. [PMID: 16462631 DOI: 10.1016/s0013-7006(05)82436-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Y Sarfati
- CH de Versailles, Hôpital Mignot, 1, rue Richaud, 78100 Versailles
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Kostova M, Passerieux C, Laurent JP, Hardy-Baylé MC. N400 anomalies in schizophrenia are correlated with the severity of formal thought disorder. Schizophr Res 2005; 78:285-91. [PMID: 15993568 DOI: 10.1016/j.schres.2005.05.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 05/15/2005] [Accepted: 05/15/2005] [Indexed: 10/25/2022]
Abstract
We explored the link between N400 anomalies and clinical profile in schizophrenia patients. N400 was recorded in 50 schizophrenia patients and 40 healthy controls during a lexical decision task with semantic priming. Comparison between controls and schizophrenia patients showed the classical anomalies reported for N400 in schizophrenia patients: greater amplitude for related words and lack of N400 effect. Analyses of the correlations between N400 effect and various symptoms of schizophrenia (formal thought disorder, positive symptoms, negative symptoms, overall symptoms, mean neuroleptic dose) or socioeducational data (age, vocabulary level, number of years of study) revealed that only the correlation with formal thought disorder was significant: the higher the scores for formal thought disorder, the lower the N400 effect observed.
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Affiliation(s)
- Milena Kostova
- Equipe de Recherche en Psychologie clinique (EAD 2027), Université Paris 8, 2 rue de la Liberté, 93526 Saint-Denis, France.
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Kiang M, Kutas M. Association of schizotypy with semantic processing differences: an event-related brain potential study. Schizophr Res 2005; 77:329-42. [PMID: 15919182 DOI: 10.1016/j.schres.2005.03.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 03/21/2005] [Accepted: 03/24/2005] [Indexed: 10/25/2022]
Abstract
Disorganized speech in both schizophrenia and schizotypy has been hypothesized to result from abnormalities in how concepts activate one another in semantic memory. To study whether schizotypy is associated with differences in how categories activate their exemplars, we examined the N400 component of the event-related brain potential (ERP) elicited during a category-verification task. ERPs were recorded in young adults from the general population while they viewed category definitions each followed by a target that was either a high-typicality exemplar, low-typicality exemplar, or non-exemplar; participants' task was to indicate whether or not the target belonged to the category. Schizotypy was assessed via the Schizotypal Personality Questionnaire (SPQ). Overall, N400 amplitude was largest for non-exemplars, smallest for high-typicality exemplars, and intermediate for low-typicality exemplars. SPQ score was associated with decreased N400 amplitude to non-exemplars, and increased amplitude to both types of exemplars. SPQ score was negatively correlated with the N400 amplitude difference between non-exemplars and both low- and high-typicality exemplars, but was not correlated with the amplitude difference between low- and high-typicality exemplars. N400 amplitude differences between non-exemplars and both types of exemplars were correlated with the SPQ Interpersonal factor, but not the Disorganized factor. The results are consistent with an association of schizotypy with decreased use of context to activate related items and inhibit unrelated items.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California-San Diego, 9500 Gilman Dr., Mail Code 0515, La Jolla, CA 92093-0515, USA.
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