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Lepock JR, Girard T, Cupid J, Kiang M. Effects of anxiety state on N400 event-related brain potential response to unexpected semantic stimuli. Neurosci Lett 2024; 826:137713. [PMID: 38458417 DOI: 10.1016/j.neulet.2024.137713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/26/2024] [Accepted: 03/01/2024] [Indexed: 03/10/2024]
Abstract
Emotional states can influence how people use meaningful context to make predictions about what comes next. To measure whether state anxiety influences such prediction, we used the N400 event-related brain potential (ERP) response to semantic stimuli, whose amplitude is smaller (less negative) when the stimulus is more predicted based on preceding context. Participants (n = 28) were randomized to one of two groups, who underwent either an "anxious-uncertainty" procedure previously shown to increase anxiety, or a control procedure. Both before and after this procedure, participants' ERPs were recorded 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") of the category. Participants' task was to respond by pressing one of two buttons to indicate whether the target represented a member of the category. As expected, based on previous work, overall, N400 amplitudes were largest (most negative) in response to non-exemplars, intermediate to low-typicality exemplars, and smallest to high-typicality exemplars. N400 amplitudes were larger to non-exemplars after the anxious-uncertainty procedure than after the control procedure. N400 amplitudes to both types of exemplars did not differ after the anxious-uncertainty procedure versus the control procedure. The results are consistent with participants devoting more neural resources to processing contextually unexpected items under anxious states, rather than anxiety facilitating processing of expected items.
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Affiliation(s)
| | - Todd Girard
- Department of Psychology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Justice Cupid
- Department of Psychology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Michael Kiang
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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Choe E, Ha M, Choi S, Park S, Jang M, Kim M, Kwon JS. Beyond verbal fluency in the verbal fluency task: semantic clustering as a predictor of remission in individuals at clinical high risk for psychosis. J Psychiatry Neurosci 2023; 48:E414-E420. [PMID: 37914223 PMCID: PMC10620004 DOI: 10.1503/jpn.230074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 07/12/2023] [Accepted: 08/04/2023] [Indexed: 11/03/2023] Open
Abstract
BACKGROUND There have been conflicting reports on whether conventional verbal fluency measures can predict the prognosis of individuals at clinical high risk (CHR) for psychosis. We aimed to investigate whether verbal fluency task measures that represent semantic processing more directly than conventional measures could be more reliable predictors of later remission in CHR individuals. METHODS We recruited CHR individuals and healthy controls to participate in a baseline verbal fluency assessment. We identified semantic clusters within the verbal fluency task responses based on cosine similarity between consecutive words, calculated from the word embedding model. Binomial logistic regression was performed to test whether average semantic cluster size and number of words produced could be predictors of remission in CHR individuals. RESULTS Our study sample included 96 CHR individuals and 178 healthy controls. According to clinical assessment at the last follow-up, 23 CHR individuals were classified as remitters and 73 as nonremitters, including 29 individuals who converted to psychosis. The CHR remitters showed larger average and maximum semantic cluster sizes than CHR nonremitters and healthy controls. Average semantic cluster size, but not the number of words, was a significant predictor of later remission in CHR individuals. LIMITATIONS Our sample included only native Korean speakers. CONCLUSION A verbal fluency task measure that more specifically represents semantic processing may be a better neurocognitive predictive marker for remission in CHR individuals than conventional verbal fluency measures. Our results provide an explanation for heterogeneous reports on whether verbal fluency can predict prognosis in CHR individuals and suggest that semantic processing is a putative cognitive predictor of their prognosis.
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Affiliation(s)
- Eugenie Choe
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
| | - Minji Ha
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
| | - Sunah Choi
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
| | - Sunghyun Park
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
| | - Moonyoung Jang
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
| | - Minah Kim
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
| | - Jun Soo Kwon
- From the Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe, Park, Jang, Kim, Kwon); the Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul, Republic of Korea (Choe); the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (Ha, Choi, Kwon); the Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Kwon)
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Lepock JR, Mizrahi R, Gerritsen CJ, Bagby RM, Maheandiran M, Ahmed S, Korostil M, Kiang M. N400 event-related brain potential and functional outcome in persons at clinical high risk for psychosis: A longitudinal study. Psychiatry Clin Neurosci 2022; 76:114-121. [PMID: 35037344 DOI: 10.1111/pcn.13330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/10/2021] [Accepted: 12/27/2021] [Indexed: 12/01/2022]
Abstract
BACKGROUND The N400 event-related brain potential (ERP) semantic priming effect is thought to reflect activation by meaningful stimuli of related concepts in semantic memory and has been found to be deficient in schizophrenia. We tested the hypothesis that, among individuals at clinical high risk (CHR) for psychosis, N400 semantic priming deficits predict worse symptomatic and functional outcomes after one year. METHODS We measured N400 semantic priming at baseline in CHR patients (n = 47) and healthy control participants (n = 25) who viewed prime words each followed by a related or unrelated target word, at stimulus-onset asynchronies (SOAs) of 300 or 750 ms. We measured patients' psychosis-like symptoms with the Scale of Prodromal Symptoms (SOPS) Positive subscale, and academic/occupational and social functioning with the Global Functioning (GF):Role and Social scales, respectively, at baseline and one-year follow-up (n = 29). RESULTS CHR patients exhibited less N400 semantic priming than controls across SOAs; planned contrasts indicated this difference was significant at the 750-ms but not the 300-ms SOA. In patients, reduced N400 semantic priming at the 750-ms SOA was associated with lower GF:Social scores at follow-up, and greater GF:Social decrements from baseline to follow-up. Patients' N400 semantic priming was not associated with SOPS Positive or GF:Role scores at follow-up, or change in these from baseline to follow-up. CONCLUSIONS In CHR patients, reduced N400 semantic priming at baseline predicted worse social functioning after one year, and greater decline in social functioning over this period. Thus, the N400 may be a useful prognostic biomarker of real-world functional outcome in CHR patients.
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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
| | - Romina Mizrahi
- Department of Psychiatry, McGill University, Montreal, Quebec, 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.,Graduate Department of Psychological Clinical Science, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | | | - Sarah Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michele Korostil
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.,St. Joseph's Healthcare Hamilton, Hamilton, 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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4
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Li F, Xu X. Impairment of semantic composition in schizophrenia: An ERP study with lexical stimuli. Neuropsychologia 2022. [DOI: 10.1016/j.neuropsychologia.2022.108241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Almeida VN, Radanovic M. Semantic priming and neurobiology in schizophrenia: A theoretical review. Neuropsychologia 2021; 163:108058. [PMID: 34655651 DOI: 10.1016/j.neuropsychologia.2021.108058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022]
Abstract
In this theoretical review we bridge the cognitive and neurobiological sciences to shed light on the neurocognitive foundations of the semantic priming effect in schizophrenia. We review and theoretically evaluate the neurotransmitter systems (dopaminergic, GABAergic and glutamatergic) and neurobiological underpinnings of behavioural and electrophysiological (N400) semantic priming in the pathology, and the main hypotheses on their geneses: a disinhibition of the semantic spread of activation, a disorganised semantic storage or noisy lexical-semantic associations, a psychomotor artefact, an artefact of relatedness proportions, or an inability to mobilise contextual information. We further assess the literature on the endophenotype of Formal Thought Disorder from multiple standpoints, ranging from neurophysiology to cognition: considerations are weaved on neuronal (PV basket cell, SST, VIP) and receptor deficits (DRD1, NMDA), neurotransmitter imbalances (dopamine), cortical and dopaminergic lateralisation, inter alia. In conclusion, we put forth novel postulates on the underlying causes of controlled hypopriming, automatic hyperpriming, N400 reversals (larger amplitudes for close associations), indirect versus direct hyperpriming, and the endophenotype of lexical-semantic disturbances in schizophrenia.
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Affiliation(s)
- Victor N Almeida
- Faculdade de Letras, Universidade Federal de Minas Gerais (UFMG), Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
| | - Marcia Radanovic
- Laboratório de Neurociências (LIM-27), Faculdade de Medicina, Departamento e Instituto de Psiquiatria, Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Brazil
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Desai A, Benner L, Wu R, Gertsik L, Maruff P, Light GA, Uz T, Marek GJ, Zhu T. Phase 1 randomized study on the safety, tolerability, and pharmacodynamic cognitive and electrophysiological effects of a dopamine D 1 receptor positive allosteric modulator in patients with schizophrenia. Neuropsychopharmacology 2021; 46:1145-1151. [PMID: 33203954 PMCID: PMC8182805 DOI: 10.1038/s41386-020-00908-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 01/29/2023]
Abstract
ASP4345, a novel dopamine D1 receptor positive allosteric modulator, is being evaluated for the treatment of cognitive impairment associated with schizophrenia (CIAS). This phase 1 multiple ascending-dose study (NCT02720263) assessed the safety, tolerability, and pharmacodynamics of ASP4345 in patients with schizophrenia/schizoaffective disorder. Pharmacodynamic assessments were Cogstate cognitive tests and electrophysiological biomarkers, including gamma-band power and phase synchronization in response to 40-Hz auditory steady-state stimulation, as well as mismatch negativity (MMN) and P3a event-related potentials. The sample size determination was based on standard practice in assessing safety and tolerability of a new chemical entity. Data were summarized by conversion of this data into effect sizes using descriptive and inferential statistics. A total of 36 randomized patients received ASP4345 (3, 15, 50, and 150 mg; n = 9 each dose) and 12 patients received placebo. Patients in the ASP4345 group experienced 73 treatment-emergent adverse events (TEAEs) and 34 TEAEs were reported for the placebo group. The most common TEAEs were headache and somnolence and nearly all TEAEs were mild in severity. No changes in mood or self-reports of suicidal ideation/behavior were observed. Improvements in performance on cognitive tests were noted, which suggests a potential improvement in psychomotor function and visual attention. Furthermore, positive changes in neurophysiological biomarkers (auditory steady-state response [ASSR] and MMN) suggest improvement in information processing. The findings need to be confirmed in studies with a larger patient population. Nonetheless, the trends in safety and pharmacodynamic data support further clinical development of ASP4345 for the treatment of CIAS.
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Affiliation(s)
- Amit Desai
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA.
| | - Lauren Benner
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Ruishan Wu
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Lev Gertsik
- grid.490279.1California Clinical Trials Medical Group, Inc., Glendale, CA USA
| | | | - Gregory A. Light
- grid.266100.30000 0001 2107 4242University of California, San Diego, San Diego, CA USA
| | - Tolga Uz
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Gerard J. Marek
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
| | - Tong Zhu
- grid.423286.90000 0004 0507 1326Astellas Pharma Global Development, Inc., Northbrook, IL USA
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7
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Lepock JR, Ahmed S, Mizrahi R, Gerritsen CJ, Maheandiran M, Drvaric L, Bagby RM, Korostil M, Light GA, Kiang M. Relationships between cognitive event-related brain potential measures in patients at clinical high risk for psychosis. Schizophr Res 2020; 226:84-94. [PMID: 30683525 DOI: 10.1016/j.schres.2019.01.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/11/2019] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
Abstract
Neurophysiological measures of cognitive functioning that are abnormal in patients with schizophrenia are promising candidate biomarkers for predicting development of psychosis in individuals at clinical high risk (CHR). We examined the relationships among event-related brain potential (ERP) measures of early sensory, pre-attentional, and attention-dependent cognition, in antipsychotic-naïve help-seeking CHR patients (n = 36) and healthy control participants (n = 22). These measures included the gamma auditory steady-state response (ASSR; early sensory); mismatch negativity (MMN) and P3a (pre-attentional); and N400 semantic priming effects - a measure of using meaningful context to predict related items - over a shorter and a longer time interval (attention-dependent). Compared to controls, CHR patients had significantly smaller P3a amplitudes (d = 0.62, p = 0.03) and N400 priming effects over the long interval (d = 0.64, p = 0.02). In CHR patients, gamma ASSR evoked power and phase-locking factor were correlated (r = 0.41, p = 0.03). Reductions in mismatch negativity (MMN) and P3a amplitudes were also correlated (r = -0.36, p = 0.04). Moreover, lower gamma ASSR evoked power correlated with smaller MMN amplitudes (r = -0.45, p = 0.02). MMN amplitude reduction was also associated with reduced N400 semantic priming over the shorter but not the longer interval (r = 0.52, p < 0.002). This pattern of results suggests that, in a subset of CHR patients, impairment in pre-attentional measures of early information processing may contribute to deficits in attention-dependent cognition involving rapid, more automatic processing, but may be independent from pathological processes affecting more controlled or strategic processing. Thus, combining neurophysiological indices of cognitive deficits in different domains offers promise for improving their predictive power as prognostic biomarkers of clinical outcome.
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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
| | | | - Lauren Drvaric
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, 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
| | - Gregory A Light
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States
| | - 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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Abstract
Schizophrenia is a severe psychiatric disorder that affects all aspects of one's life with several cognitive and social dysfunctions. However, there is still no objective and universal index for diagnosis and treatment of this disease. Many researchers have studied language processing in schizophrenia since most of the patients show symptoms related to language processing, such as thought disorder, auditory verbal hallucinations, or delusions. Electroencephalography (EEG) and magnetoencephalography (MEG) with millisecond order high temporal resolution, have been applied to reveal the abnormalities in language processing in schizophrenia. The aims of this review are (a) to provide an overview of recent findings in language processing in schizophrenia with EEG and MEG using neurophysiological indices, providing insights into underlying language related pathophysiological deficits in this disease and (b) to emphasize the advantage of EEG and MEG in research on language processing in schizophrenia.
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Affiliation(s)
- Shogo Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashiku, Fukuoka, Japan.,Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Kevin M Spencer
- Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Toshiaki Onitsuka
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashiku, Fukuoka, Japan
| | - Yoji Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashiku, Fukuoka, Japan.,Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, MA, USA
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9
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Light GA, Joshi YB, Molina JL, Bhakta SG, Nungaray JA, Cardoso L, Kotz JE, Thomas ML, Swerdlow NR. Neurophysiological biomarkers for schizophrenia therapeutics. Biomark Neuropsychiatry 2020. [DOI: 10.1016/j.bionps.2020.100012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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10
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Kiang M, Cupid J, Ahmed S, Lepock JR, Girard TA. Religiosity is associated with less prediction of the typical: An event-related brain potential study. Biol Psychol 2020; 153:107884. [PMID: 32234502 DOI: 10.1016/j.biopsycho.2020.107884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/04/2020] [Accepted: 03/23/2020] [Indexed: 11/26/2022]
Abstract
Why are some people more religious than others? According to one hypothesis, people who strongly seek definitive explanations for situations with incomplete information are more likely to be religious. According to a different hypothesis, individuals with smaller "prediction error" responses to unexpected stimuli are more likely to discount evidence contradicting religious beliefs, predisposing them to maintain such beliefs. We sought neurophysiological evidence for these hypotheses using the N400 event-related potential (ERP), which is smaller to more contextually expected stimuli, reflecting prediction of probable completions for meaningful situations. We recorded ERPs from participants viewing category definitions followed by high-typicality category exemplar (HTE), low-typicality exemplar (LTE), or non-exemplar (NE) words. As expected, N400s were largest for NEs, intermediate for LTEs, and smallest for HTEs. Religiosity correlated with smaller N400 amplitude differences between HTEs and both LTEs and NEs. Less strong prediction of probable stimuli based on prior information may predispose to religiosity.
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Affiliation(s)
- Michael Kiang
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Justice Cupid
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychology, Ryerson University, Toronto, ON, Canada
| | - Sarah Ahmed
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Jennifer R Lepock
- Centre for Addiction and Mental Health, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Todd A Girard
- Department of Psychology, Ryerson University, Toronto, ON, Canada
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11
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Wang K, Zhao YL, Tan SP, Zhang JG, Li D, Chen JX, Zhang LG, Yu XY, Zhao D, Cheung EFC, Turetsky BI, Gur RC, Chan RCK. Semantic processing event‐related potential features in patients with schizophrenia and bipolar disorder. Psych J 2019; 9:247-257. [PMID: 31788984 DOI: 10.1002/pchj.321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Kui Wang
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Li Zhao
- Beijing Huilongguan Hospital, Beijing, China
| | | | | | - Dong Li
- Beijing Huilongguan Hospital, Beijing, China
| | | | | | - Xin-Yang Yu
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Dan Zhao
- School of Education, Changchun Normal University, Changchun, China
| | | | - Bruce I Turetsky
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ruben C Gur
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Raymond C K Chan
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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12
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Kiang M, Gerritsen CJ. The N400 event-related brain potential response: A window on deficits in predicting meaning in schizophrenia. Int J Psychophysiol 2019; 145:65-9. [DOI: 10.1016/j.ijpsycho.2019.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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13
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Ibáñez-Molina AJ, Lozano V, Soriano MF, Aznarte JI, Gómez-Ariza CJ, Bajo MT. EEG Multiscale Complexity in Schizophrenia During Picture Naming. Front Physiol 2018; 9:1213. [PMID: 30245636 PMCID: PMC6138007 DOI: 10.3389/fphys.2018.01213] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/13/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: Patients with schizophrenia show cognitive deficits that are evident both behaviourally and with EEG recordings. Recent studies have suggested that non-linear analyses of EEG might more adequately reflect the complex, irregular, non-stationary behavior of neural processes than more traditional ERP measures. Non-linear analyses have been mainly applied to EEGs from patients at rest, whereas differences in complexity might be more evident during task performance. Objective: We aimed to investigate changes in non-linear brain dynamics of patients with schizophrenia during cognitive processing. Method: 18 patients and 17 matched healthy controls were asked to name pictures. EEG data were collected at rest and while they were performing a naming task. EEGs were analyzed with the classical Lempel-Ziv Complexity (LZC) and with the Multiscale LZC. Electrodes were grouped in seven regions of interest (ROI). Results: As expected, controls had fewer naming errors than patients. Regarding EEG complexity, the interaction between Group, Task and ROI indicated that patients showed higher complexity values in right frontal regions only at rest, where no differences in complexity between patients and controls were found during the naming task. EEG complexity increased from rest to task in controls in left temporal-parietal regions, while no changes from rest to task were observed in patients. Finally, differences in complexity between patients and controls depended on the frequency bands: higher values of complexity in patients at rest were only observed in fast bands, indicating greater heterogeneity in patients in local dynamics of neuronal assemblies. Conclusion: Consistent with previous studies, schizophrenic patients showed higher complexity than controls in frontal regions at rest. Interestingly, we found different modulations of brain complexity during a simple cognitive task between patients and controls. These data can be interpreted as indicating schizophrenia-related failures to adapt brain functioning to the task, which is reflected in poorer behavioral performance.
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Affiliation(s)
| | - Vanessa Lozano
- Department of Experimental Psychology, University of Granada, Granada, Spain
| | | | | | | | - M T Bajo
- Department of Experimental Psychology, University of Granada, Granada, Spain
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Schoenberg PLA, Barendregt HP. Mindful Disintegration and the Decomposition of Self in Healthy Populations: Conception and Preliminary Study. Psychol Stud 2016; 61:307-20. [DOI: 10.1007/s12646-016-0374-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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15
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Spataro P, Saraulli D, Cestari V, Costanzi M, Sciarretta A, Rossi-Arnaud C. Implicit memory in schizophrenia: a meta-analysis. Compr Psychiatry 2016; 69:136-44. [PMID: 27423354 DOI: 10.1016/j.comppsych.2016.05.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 05/10/2016] [Accepted: 05/21/2016] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Previous studies examining implicit memory in schizophrenia yielded inconsistent results. The present meta-analysis aimed at determining whether, compared to healthy controls, schizophrenic patients: (a) exhibited reduced priming in the whole set of studies; (b) were differentially impaired in conceptual/perceptual and production/identification tests; and (c) were less efficient in the use of semantic encoding processes. METHOD A systematic search in PsycINFO and PubMed led to the selection of 22 critical studies (31 effect sizes), comparing repetition priming in 836 schizophrenic patients and 760 healthy controls. Moderators were assessed by classifying implicit tasks into the perceptual/conceptual and identification/production categories, and by distinguishing between perceptual and conceptual encoding instructions. RESULTS Overall, implicit memory was slightly, but significantly, impaired in schizophrenia (d=0.179). Patients exhibited reduced priming in conceptually-driven tasks (d=0.447), but intact priming in perceptually-driven tasks (d=0.080). No significant difference was observed between identification and production priming (d=0.064 vs. d=0.243). Finally, priming in schizophrenic patients was significantly lower than that of controls when the encoding task required the analysis of the conceptual properties of the stimuli (d=0.261). CONCLUSION Results suggest that schizophrenia is associated with a specific deficit in the use of conceptual processes, both at encoding and at retrieval. In contrast with theoretical expectations, high levels of response competition did not disproportionately impair the patients' performance.
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Affiliation(s)
- Pietro Spataro
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185, Rome, Italy
| | - Daniele Saraulli
- Cell Biology and Neurobiology Institute, C.N.R National Research Council of Italy, Via del Fosso di Fiorano 64/65, 00143, Rome, Italy; University LUMSA of Rome, Department of Human Sciences, Piazza delle Vaschette 101, 00193, Rome, Italy
| | - Vincenzo Cestari
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185, Rome, Italy; Cell Biology and Neurobiology Institute, C.N.R National Research Council of Italy, Via del Fosso di Fiorano 64/65, 00143, Rome, Italy
| | - Marco Costanzi
- Cell Biology and Neurobiology Institute, C.N.R National Research Council of Italy, Via del Fosso di Fiorano 64/65, 00143, Rome, Italy; University LUMSA of Rome, Department of Human Sciences, Piazza delle Vaschette 101, 00193, Rome, Italy
| | - Antonio Sciarretta
- Acute Psychiatric Care Unit, Department of Mental Health RM-G, San Giovanni Evangelista Hospital, Via Antonio Parrozzani 3, 00019, Tivoli, Italy
| | - Clelia Rossi-Arnaud
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185, Rome, Italy.
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Conde T, Gonçalves OF, Pinheiro AP. A Cognitive Neuroscience View of Voice-Processing Abnormalities in Schizophrenia: A Window into Auditory Verbal Hallucinations? Harv Rev Psychiatry 2016; 24:148-63. [PMID: 26954598 DOI: 10.1097/HRP.0000000000000082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Auditory verbal hallucinations (AVH) are a core symptom of schizophrenia. Like "real" voices, AVH carry a rich amount of linguistic and paralinguistic cues that convey not only speech, but also affect and identity, information. Disturbed processing of voice identity, affective, and speech information has been reported in patients with schizophrenia. More recent evidence has suggested a link between voice-processing abnormalities and specific clinical symptoms of schizophrenia, especially AVH. It is still not well understood, however, to what extent these dimensions are impaired and how abnormalities in these processes might contribute to AVH. In this review, we consider behavioral, neuroimaging, and electrophysiological data to investigate the speech, identity, and affective dimensions of voice processing in schizophrenia, and we discuss how abnormalities in these processes might help to elucidate the mechanisms underlying specific phenomenological features of AVH. Schizophrenia patients exhibit behavioral and neural disturbances in the three dimensions of voice processing. Evidence suggesting a role of dysfunctional voice processing in AVH seems to be stronger for the identity and speech dimensions than for the affective domain.
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Glyn V, Lim VK, Hamm JP, Mathur A, Hughes B. Behavioural and electrophysiological effects related to semantic violations during braille reading. Neuropsychologia 2015; 77:298-312. [PMID: 26359716 DOI: 10.1016/j.neuropsychologia.2015.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 09/04/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022]
Abstract
This study investigated the potential to detect event related potentials (ERPs) occurring in response to a specific task in braille reading. This would expand current methodologies for studying the cognitive processes underlying braille reading. An N400 effect paradigm was utilised, whereby proficient blind braille readers read congruent- and incongruent-ending braille sentences. Kinematic and electroencephalography (EEG) data were obtained simultaneously and synchronised. The ERPs differed between the incongruent and congruent sentences in a manner consistent with the N400 effect found with a previous sighted reading paradigm, demonstrating that ERPs can be obtained during braille reading. The frequency of finger reversals and the degree of intermittency in the finger velocity were significantly higher when reading incongruent versus congruent sentence endings. Both reversals and the potential N400 effect may reflect processes involved in semantic unification. These findings have significant implications for the modelling of braille reading. The refinement of the technique will enable other ERPs to be identified and related to behavioural responses, to further our understanding of the braille reading process.
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Affiliation(s)
- Vania Glyn
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Vanessa K Lim
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jeff P Hamm
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Ashwin Mathur
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Barry Hughes
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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Luka BJ, Van Petten C. Gradients versus dichotomies: how strength of semantic context influences event-related potentials and lexical decision times. Cogn Affect Behav Neurosci 2014; 14:1086-103. [PMID: 24310943 DOI: 10.3758/s13415-013-0223-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In experiments devoted to word recognition and/or language comprehension, reaction time in the lexical decision task is perhaps the most commonly used behavioral dependent measure, and the amplitude of the N400 component of the event-related potential (ERP) is the most common neural measure. Both are sensitive to multiple factors, including frequency of usage, orthographic similarity to other words, concreteness of word meaning, and preceding semantic context. All of these factors vary continuously. Published results have shown that both lexical decision times and N400 amplitudes show graded responses to graded changes of word frequency and orthographic similarity, but a puzzling discrepancy in their responsivity to the strength of a semantic context has received little attention. In three experiments, we presented pairs of words varying in the strengths of their semantic relationships, as well as unrelated pairs. In all three experiments, N400 amplitudes showed a gradient from unrelated to weakly associated to strongly associated target words, whereas lexical decision times showed a binary division rather than a gradient across strengths of relationship. This pattern of results suggests that semantic context effects in lexical decision and ERP measures arise from fundamentally different processes.
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19
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Pinheiro AP, Del Re E, Nestor PG, Mezin J, Rezaii N, McCarley RW, Gonçalves ÓF, Niznikiewicz M. Abnormal interactions between context, memory structure, and mood in schizophrenia: an ERP investigation. Psychophysiology 2015; 52:20-31. [PMID: 25047946 DOI: 10.1111/psyp.12289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 06/08/2014] [Indexed: 02/06/2023]
Abstract
This study used event-related potentials to examine interactions between mood, sentence context, and semantic memory structure in schizophrenia. Seventeen male chronic schizophrenia and 15 healthy control subjects read sentence pairs after positive, negative, or neutral mood induction. Sentences ended with expected words (EW), within-category violations (WCV), or between-category violations (BCV). Across all moods, patients showed sensitivity to context indexed by reduced N400 to EW relative to both WCV and BCV. However, they did not show sensitivity to the semantic memory structure. N400 abnormalities were particularly enhanced under a negative mood in schizophrenia. These findings suggest abnormal interactions between mood, context processing, and connections within semantic memory in schizophrenia, and a specific role of negative mood in modulating semantic processes in this disease.
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Affiliation(s)
- Ana P Pinheiro
- Neuropsychophysiology Laboratory, CIPsi, School of Psychology, University of Minho, Braga, Portugal; Cognitive Neuroscience Laboratory, Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
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20
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Jackson F, Foti D, Kotov R, Perlman G, Mathalon DH, Proudfit GH. An incongruent reality: the N400 in relation to psychosis and recovery. Schizophr Res 2014; 160:208-15. [PMID: 25449716 PMCID: PMC4258120 DOI: 10.1016/j.schres.2014.09.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/22/2014] [Accepted: 09/24/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Cognitive impairments and delusions are hallmarks of schizophrenia, and are thought to be due in part to abnormalities in semantic priming. The N400, a neural measure of semantic processing, is found to be reduced in schizophrenia. However, it is unclear if individuals with other psychoses (e.g., mood disorders or substance abuse with psychotic features) also show this impairment, and whether N400 reduction relates to real-world functioning and recovery. METHODS Eighty-nine individuals from the Suffolk County Mental Health Project, a longitudinal study of first-admission psychosis, and 35 healthy adults were assessed using matched, related, and unrelated picture-word pairs to elicit the N400. Patients' real-world functioning, symptomatology, and recovery were tracked since first hospitalization; EEG assessment was completed during year 15 of the study. RESULTS Participants with schizophrenia had slower reaction times and reduced N400 to semantically incongruent stimuli relative to healthy participants. Schizophrenia and other psychoses did not differ on N400, suggesting that N400 abnormalities characterize psychosis broadly. When grouped by recovery status, patients who remained ill had a significantly blunted N400, while those who recovered did not differ from healthy adults. Few patients with schizophrenia achieved recovery; therefore recovery results are limited to the other psychosis group. Furthermore, reduced N400 and increased reaction times correlated with greater psychotic symptoms, worse global assessment of functioning scores, unemployment, and impaired social functioning. CONCLUSIONS Abnormalities in the N400 are not specific to schizophrenia; in addition, the N400 may be a useful neural correlate of recovery and real-world functioning across psychotic disorders.
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Affiliation(s)
- Felicia Jackson
- Department of Psychology, Stony Brook University, Stony Brook, NY, United States.
| | - Dan Foti
- Department of Psychological Sciences, Purdue University, West
Lafayette, IN
| | - Roman Kotov
- Department of Psychiatry and Behavioral Sciences, Stony Brook
University, Stony Brook, NY
| | - Greg Perlman
- Department of Psychiatry and Behavioral Sciences, Stony Brook
University, Stony Brook, NY
| | - Daniel H. Mathalon
- Department of Psychiatry, University of California San Francisco,
San Francisco, CA
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Boyd JE, Patriciu I, McKinnon MC, Kiang M. 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: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [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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22
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Besche-Richard C, Iakimova G, Hardy-Baylé MC, Passerieux C. Behavioral and brain measures (N400) of semantic priming in patients with schizophrenia: test-retest effect in a longitudinal study. Psychiatry Clin Neurosci 2014; 68:365-73. [PMID: 24405516 DOI: 10.1111/pcn.12137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 10/18/2013] [Accepted: 10/28/2013] [Indexed: 11/29/2022]
Abstract
AIM The purpose of this study was to investigate whether deficits in the behavioral and/or N400 semantic priming (SP) effect observed in patients with schizophrenia constitute a stable cognitive feature of the disorder or whether they may be influenced by the severity of each individual's symptomatology. METHODS A 1-year test-retest study was conducted on 15 patients with schizophrenia and 10 healthy participants who performed an SP task. Both behavioral measures and event-related potentials measures of SP were recorded twice (test and retest sessions). RESULTS At test, patients exhibited a deficit in SP as was revealed by both the behavioral and the event-related potentials measures of the amplitude of the N400 component. At retest, behavioral SP remained impaired, whereas N400 SP was significantly improved. CONCLUSION These results provide evidence that SP impairments in schizophrenia as measured by N400 should not be considered as stable cognitive markers of the disorder. The behavioral and the N400 measures of SP indicated different levels of sensitivity to subtle cognitive and brain processes, which are subject to change over the clinical course of schizophrenic disorder.
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Affiliation(s)
- Chrystel Besche-Richard
- Cognition, Health and Socialization Laboratory, Reims Champagne-Ardenne University, Reims, France; French University Institute, Paris, France
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Cermolacce M, Faugère M, Micoulaud-Franchi JA, Belzeaux R, Maurel M, Naudin J, Azorin JM, Vion-Dury J. Natural speech comprehension in bipolar disorders: an event-related brain potential study among manic patients. J Affect Disord 2014; 158:161-71. [PMID: 24655781 DOI: 10.1016/j.jad.2013.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 10/13/2013] [Accepted: 11/20/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Thought and language disturbances are crucial clinical features in Bipolar Disorders (BD), and constitute a fundamental basis for social cognition. In BD, clinical manifestations such as disorganization and formal thought disorders may play a role in communication disturbances. However, only few studies have explored language disturbances in BD at a neurophysiological level. Two main Event-Related brain Potentials (ERPs) have been used in language comprehension research: the N400 component, elicited by incongruous word with the preceding semantic context, and the Late Positive Component (LPC), associated with non-specifically semantic and more general cognitive processes. Previous studies provided contradictory results regarding N400 in mood disorders, showing either preserved N400 in depression or dysthymia, or altered N400 in BD during semantic priming paradigm. The aim of our study was to explore N400 and LPC among patients with BD in natural speech conditions. METHODS ERPs from 19 bipolar type I patients with manic or hypomanic symptomatology and 19 healthy controls were recorded. Participants were asked to listen to congruous and incongruous complete sentences and to judge the match between the final word and the sentence context. Behavioral results and ERPs data were analyzed. RESULTS At the behavioral level, patients with BD show worst performances than healthy participants. At the electrophysiological level, our results show preserved N400 component in BD. LPC elicited under natural speech conditions shows preserved amplitude but delayed latency in difference waves. LIMITATIONS Small size of samples, absence of schizophrenic group and medication status. CONCLUSIONS In contrast with the only previous N400 study in BD that uses written semantic priming, our results show a preserved N400 component in ecological and natural speech conditions among patients with BD. Possible implications in terms of clinical specificity are discussed.
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Affiliation(s)
- Michel Cermolacce
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France; Unité de Neurophysiologie, Psychophysiologie et Neurophénoménologie (UNPN), UF 4817, CHU Sainte Marguerite, Marseille, France; Laboratoire de Neurosciences Cognitives, UMR CNRS 7291 & Aix-Marseille Université, Fédération 3C, Marseille, France.
| | - Mélanie Faugère
- Unité de Neurophysiologie, Psychophysiologie et Neurophénoménologie (UNPN), UF 4817, CHU Sainte Marguerite, Marseille, France; Laboratoire de Neurosciences Cognitives, UMR CNRS 7291 & Aix-Marseille Université, Fédération 3C, Marseille, France
| | - Jean-Arthur Micoulaud-Franchi
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France; Unité de Neurophysiologie, Psychophysiologie et Neurophénoménologie (UNPN), UF 4817, CHU Sainte Marguerite, Marseille, France; Laboratoire de Neurosciences Cognitives, UMR CNRS 7291 & Aix-Marseille Université, Fédération 3C, Marseille, France; FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France
| | - Raoul Belzeaux
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France; CRN2M, UMR 7286 & Aix-Marseille Université, Marseille, France; FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France
| | - Muriel Maurel
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France
| | - Jean Naudin
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France; Unité de Neurophysiologie, Psychophysiologie et Neurophénoménologie (UNPN), UF 4817, CHU Sainte Marguerite, Marseille, France; Laboratoire de Neurosciences Cognitives, UMR CNRS 7291 & Aix-Marseille Université, Fédération 3C, Marseille, France
| | - Jean-Michel Azorin
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France; Institut de Neurosciences de la Timone (INT), UMR CNRS 7289 & Aix-Marseille Université, Marseille, France; FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, France
| | - Jean Vion-Dury
- Département Universitaire de Psychiatrie, CHU Sainte Marguerite and Aix-Marseille Université, Marseille, France; Unité de Neurophysiologie, Psychophysiologie et Neurophénoménologie (UNPN), UF 4817, CHU Sainte Marguerite, Marseille, France; Laboratoire de Neurosciences Cognitives, UMR CNRS 7291 & Aix-Marseille Université, Fédération 3C, Marseille, France; FondaMental, Fondation de Recherche et de Soins en Santé Mentale, Créteil, 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Abstract
Patients with schizophrenia have been hypothesized to have a functional impairment in filtering irrelevant sensory information, which may result in positive symptoms such as hallucinations or delusions. Many evidences suggest that abnormalities in the event-related brain potentials (ERPs), resting state electroencephalography (EEG) and synchronized oscillatory activity of neurons may reflect core pathophysiological mechanisms of schizophrenia. Abnormalities in amplitude and latency of the ERPs reflecting aberrations in gating and difficulties in the detection of changes in auditory stimuli, as well as defects in stimuli evaluation and integration of information are common in patients with schizophrenia. This chapter highlights the findings of electrophysiological studies in schizophrenia dealing with early sensory perception and attention, automatic sensory detection of stimuli changes and cognitive evaluation and integration of information, relevant to the pathophysiological mechanisms underpinning hallucinations and delusions. Results of electrophysiological studies investigating the neural correlates of positive symptoms suggest aberrant intrinsic organization of functional brain networks.
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Affiliation(s)
- Silvana Galderisi
- Department of Psychiatry, University of Naples SUN, Largo Madonna delle Grazie, 80138, Naples, NA, Italy,
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Hasey GM, Kiang M. A review of recent literature employing electroencephalographic techniques to study the pathophysiology, phenomenology, and treatment response of schizophrenia. Curr Psychiatry Rep 2013; 15:388. [PMID: 23933976 DOI: 10.1007/s11920-013-0388-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Clinical experience and research findings suggest that schizophrenia is a disorder comprised of multiple genetic and neurophysiological subtypes with differential response to treatment. Electroencephalography (EEG) is a non-invasive, inexpensive and useful tool for investigating the neurobiology of schizophrenia and its subtypes. EEG studies elucidate the neurophysiological mechanisms potentially underlying clinical symptomatology. In this review article recent advances in applying EEG to study pathophysiology, phenomenology, and treatment response in schizophrenia are discussed. Investigative strategies employed include: analyzing quantitative EEG (QEEG) spectral power during the resting state and cognitive tasks; applying machine learning methods to identify QEEG indicators of diagnosis and treatment response; and using the event-related brain potential (ERP) technique to characterize the neurocognitive processes underlying clinical symptoms. Studies attempting to validate potential EEG biomarkers of schizophrenia and its symptoms, which could be useful in assessing familial risk and treatment response, are also reviewed.
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Chen PJ, Fan LY, Hwang TJ, Hwu HG, Liu CM, Chou TL. The deficits on a cortical-subcortical loop of meaning processing in schizophrenia. Neuroreport 2013; 24:147-51. [PMID: 23324649 DOI: 10.1097/WNR.0b013e32835df562] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Thought disorder is a core symptom of schizophrenia. However, the underlying mechanism is not well understood. Functional MRI (fMRI) was used to examine the neural mechanism of thought disorder in 20 patients with schizophrenia and 20 healthy controls during semantic judgments. Two indexes of disorganized thought were further used to evaluate individual differences in thought disturbance in the patients. Compared with the controls, the patients showed greater activation in left inferior frontal gyrus (BA45) and reduced activation in the left caudate nucleus for meaning-related pairs. Moreover, in patients, effective connectivity from Dynamic Causal Modeling showed that the modulatory effect from the caudate nucleus to the inferior frontal gyrus was weaker than that in controls, indicating a disrupted cortical-subcortical language loop for semantic processing in patients. Finally, increasing scores of disorganized thought were correlated with greater activation in the inferior frontal gyrus and weaker connection strength from the caudate nucleus to the inferior frontal gyrus. Patients with more severe disorganized symptoms might receive less efficient regulation from the caudate nucleus, resulting in increased demands for the inferior frontal gyrus to retrieve or select semantic knowledge in the cortical-subcortical circuit.
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Hella P, Niemi J, Hintikka J, Otsa L, Tirkkonen JM, Koponen H. Disordered semantic activation in disorganized discourse in schizophrenia: a new pragma-linguistic tool for structure and meaning reconstruction. Int J Lang Commun Disord 2013; 48:320-328. [PMID: 23650888 DOI: 10.1111/1460-6984.12011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND Disorganized speech, manifested as derailment, tangentiality, incoherence and loss of goal, occurs commonly in schizophrenia. Studies of language processing have demonstrated that semantic activation in schizophrenia is often disordered and, moreover, the ability to use contextual cues is impaired. AIMS To reconstruct the origins and most plausible intended meanings of disorganized discourse sequences in a clinical interview with a patient with thought-disordered schizophrenia. METHODS & PROCEDURES We assessed the so-called pragmatic felicity of every turn using a novel tool called the Overall Comprehensibility of Turn (OCT) Scale. In addition to felicity analysis, all topics and referents of turns were registered. Three most disorganized discourse sequences from the transcribed interview were chosen for the thematic and semantic analysis, in which we attempted to reconstruct the structure and meaning of those sequences utilizing (1) the notion of discourse model extending up to contextual background knowledge, (2) the (re)occurrence of topical items, together with (3) the knowledge from findings of disordered semantic activation in schizophrenia. OUTCOMES & RESULTS The linguistic analyses showed that the disrupted sequences were characterized by (1) unexpected, seemingly irrelevant topic intrusion, (2) pragmatically inappropriate chain of topic extensions, and (3) fuzzy reference together with disturbed ordering of propositions. The underlying causes seemed to be, respectively, (1) long-term semantic activation of topics, which popped out sporadically along the conversation, (2) overreliance on lexical-semantic associations, and (3) the inability to sequence the utterances and link them together using explicit or implicit bridging assumptions necessary to a coherent and cohesive message. All scrutinized passages violated the expectations of the addressee in on-line conversation. However, the post-hoc analysis showed that they contained items which were relevant to the global topic. CONCLUSIONS & IMPLICATIONS Latent sources, motivations and even meanings, at least to some extent, of seemingly disorganized utterances can become analysable through linguistic analyses. The results suggest that continuity in the treatment is essential, because a practitioner who shares background knowledge with the patient has better opportunities to capture the relevance of the superficially disorganized utterances. Moreover, especially the most disorganized sequences should warrant thorough attention because they can convey, beneath their unexpected or obscure surface structure, items which are psychologically important to the patient. The results of this study should be taken into account in the training of interactional skills of professionals who work with schizophrenia patients.
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Affiliation(s)
- Pertti Hella
- Department of Psychiatry, Kuopio University Hospital, Kuopio, Finland.
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Debruille JB, Rodier M, Prévost M, Lionnet C, Molavi S. Effects of a small dose of olanzapine on healthy subjects according to their schizotypy: an ERP study using a semantic categorization and an oddball task. Eur Neuropsychopharmacol 2013; 23:339-50. [PMID: 22748420 DOI: 10.1016/j.euroneuro.2012.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/23/2012] [Accepted: 06/07/2012] [Indexed: 11/18/2022]
Abstract
Delusions and hallucinations are often meaningful. They thus reveal abnormal semantic activations. To start testing whether antipsychotics act by reducing abnormal semantic activations we focused on the N400 event-related brain potential, which is elicited by meaningful stimuli, such as words, and whose distribution on the scalp is known to depend on the semantic category of these stimuli. We used a semantic-categorization task specially designed to reduce the impact of the variations of context processing across subjects' groups and a classical oddball task as a control. Healthy subjects were recruited rather than psychotic patients to ensure that the medication effects could not be secondary to a reduction of symptoms. These participants (n=47) were tested in a double-blind cross-over paradigm where the ERP effects of 2.5mg of olanzapine taken on the eve of the testing were compared to those of the placebo. The amplitudes of the N400s elicited by the target words were greater at anterior scalp sites in the half of the subjects having higher schizotypal scores. Olanzapine reduced these larger N400s and had no effect on the small anterior N400s of the half of the subjects with lower scores. These results are discussed as consistent with the idea that antipsychotics reduce abnormal activations of particular semantic representations. Further studies should thus be done to see if this reduction correlates with and predicts the decrease of psychotic symptoms in patients.
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Affiliation(s)
- J Bruno Debruille
- Research Center of the Douglas Mental Health University Institute, Montréal, Québec, Canada.
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Cermolacce M, Micoulaud-franchi J, Faugere M, Naudin J, Besson M, Vion-dury J. 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] [What about the content of this article? (0)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Takahashi H, Rissling AJ, Pascual-Marqui R, Kirihara K, Pela M, Sprock J, Braff DL, Light GA. Neural substrates of normal and impaired preattentive sensory discrimination in large cohorts of nonpsychiatric subjects and schizophrenia patients as indexed by MMN and P3a change detection responses. Neuroimage 2012; 66:594-603. [PMID: 23085112 DOI: 10.1016/j.neuroimage.2012.09.074] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 09/25/2012] [Accepted: 09/30/2012] [Indexed: 10/27/2022] Open
Abstract
OBJECTIVE Schizophrenia (SZ) patients have information processing deficits, spanning from low level sensory processing to higher-order cognitive functions. Mismatch negativity (MMN) and P3a are event-related potential (ERP) components that are automatically elicited in response to unattended changes in ongoing, repetitive stimuli that provide a window into abnormal information processing in SZ. MMN and P3a are among the most robust and consistently identified deficits in SZ, yet the neural substrates of these responses and their associated deficits in SZ are not fully understood. This study examined the neural sources of MMN and P3a components in a large cohort of SZ and nonpsychiatric control subjects (NCS) using Exact Low Resolution Electromagnetic Tomography Analyses (eLORETA) in order to identify the neural sources of MMN and P3a as well as the brain regions associated with deficits commonly observed among SZ patients. METHODS 410 SZ and 247 NCS underwent EEG testing using a duration-deviant auditory oddball paradigm (1-kHz tones, 500ms SOA; standard p=0.90, 50-ms duration; deviant tones P=0.10, 100-ms duration) while passively watching a silent video. Voxel-by-voxel within- (MMN vs. P3a) and between-group (SZ vs. NCS) comparisons were performed using eLORETA. RESULTS SZ had robust deficits in MMN and P3a responses measured at scalp electrodes consistent with other studies. These components mapped onto neural sources broadly distributed across temporal, frontal, and parietal regions. MMN deficits in SZ were associated with reduced activations in discrete medial frontal brain regions, including the anterior-posterior cingulate and medial frontal gyri. These early sensory discriminatory MMN impairments were followed by P3a deficits associated with widespread reductions in the activation of attentional networks (frontal, temporal, parietal regions), reflecting impaired orienting or shifts of attention to the infrequent stimuli. CONCLUSIONS MMN and P3a are dissociable responses associated with broadly distributed patterns of neural activation. MMN deficits among SZ patients appear to be primarily accounted for by reductions in medial prefrontal brain regions that are followed by widespread dysfunction across cortical networks associated with P3a in a manner that is consistent with hierarchical information processing models of cognitive deficits in SZ patients. Impairments in automatic stimulus discrimination may contribute to higher-order cognitive and psychosocial deficits in SZ.
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Affiliation(s)
- Hidetoshi Takahashi
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; Department of Child and Adolescent Mental Health, National Institute of Mental Health, National Center of Neurology and Psychiatry, Japan
| | - Anthony J Rissling
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Roberto Pascual-Marqui
- The KEY Institute for Brain-Mind Research, University Hospital of Psychiatry, Zurich, Switzerland
| | - Kenji Kirihara
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Marlena Pela
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Joyce Sprock
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; VISN-22 Mental Illness, Research, Education and Clinical Center, VA San Diego Healthcare System, USA
| | - David L Braff
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; VISN-22 Mental Illness, Research, Education and Clinical Center, VA San Diego Healthcare System, USA
| | - Gregory A Light
- VISN-22 Mental Illness, Research, Education and Clinical Center, VA San Diego Healthcare System, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
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Kimble MO, Batterink L, Marks E, Ross C, Fleming K. Negative expectancies in posttraumatic stress disorder: neurophysiological (N400) and behavioral evidence. J Psychiatr Res 2012; 46:849-55. [PMID: 22595869 PMCID: PMC3936679 DOI: 10.1016/j.jpsychires.2012.03.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 03/26/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Posttraumatic stress disorder (PTSD) is a disorder that theoretically and clinically is thought to be associated with persistent and exaggerated negative expectancies. This study used the N400 event-related potential (ERP) to investigate expectancies for threatening endings to ambiguous sentence stems. The N400 ERP is thought to reflect the amount of effort required to integrate a stimulus into a given context. In sentence reading tasks, the N400 is reliably larger when a word is unexpected. METHOD In this study, fifty-seven trauma survivors of various types (22 with PTSD and 35 without) read ambiguous sentence stems on a computer screen. These sentence stems were completed with either an expected ("The unfortunate man lost his…wallet"), unexpected ("The unfortunate man lost his…artist"), or threatening word endings ("The unfortunate man lost his…leg"). RESULTS Participants with PTSD, as compared to those without, showed significantly smaller N400s to threatening sentence endings suggesting enhanced expectancies for threat. Behavioral responses supported this conclusion. CONCLUSIONS These findings are consistent with the clinical presentation of hypervigilance and proposed revisions to the DSM-V that emphasize persistent and exaggerated negative expectations about one's self, others, or the world. Relative to earlier behavioral studies, this work further suggests that this expectancy bias occurs automatically and at the early stages of information processing. The discussion focuses on the potential impact of a negative expectancy bias in PTSD and the value of the ambiguous sentence paradigm for studying PTSD as well as other disorders.
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Kiang M, Christensen BK, Kutas M, Zipursky RB. Electrophysiological evidence for primary semantic memory functional organization deficits in schizophrenia. Psychiatry Res 2012; 196:171-80. [PMID: 22460130 PMCID: PMC4075227 DOI: 10.1016/j.psychres.2012.02.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 10/28/2011] [Accepted: 02/21/2012] [Indexed: 11/29/2022]
Abstract
N400, an event-related brain potential (ERP) waveform elicited by meaningful stimuli, is normally reduced by stimulus repetition (N400 repetition priming), and relatedness between the eliciting stimulus and preceding ones (relatedness priming). Schizophrenia patients' N400 relatedness priming deficits suggest impairment in using meaningful prime stimuli to facilitate processing of related concepts in semantic memory. To examine whether this deficiency arises from difficulty activating the prime concept per se, as indexed by reduced N400 repetition priming; or from impaired functional connections among concepts in semantic memory, as reflected by reduced relatedness priming but normal repetition priming; we recorded ERPs from 16 schizophrenia patients and 16 controls who viewed prime words each followed at 300- or 750-ms stimulus-onset asynchrony (SOA) by an unrelated, related or repeated target word, or a nonword, in a lexical-decision task. In both groups, N400s were largest (most negative) for unrelated, intermediate for related, and smallest for repeated targets. Schizophrenia patients exhibited subnormal N400 relatedness priming at the 300-ms SOA, but normal repetition priming at both SOAs, suggesting that their impairment in using prime words to activate related concepts results from abnormal functional connections among concepts within semantic memory, rather than inability to activate the prime concept itself.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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Kiang M, Christensen BK, Zipursky RB. Depth-of-processing effects on semantic activation deficits in schizophrenia: an electrophysiological investigation. Schizophr Res 2011; 133:91-8. [PMID: 21868201 DOI: 10.1016/j.schres.2011.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/29/2011] [Accepted: 08/01/2011] [Indexed: 11/16/2022]
Abstract
N400, an event-related brain potential (ERP) waveform elicited by meaningful stimuli, is normally reduced (made less negative) by relatedness between the eliciting stimulus and preceding ones (N400 semantic priming). Schizophrenia patients' N400 semantic priming deficits suggest impairment in using meaningful context to activate related concepts in semantic memory. We aimed to examine the degree to which this impairment can be ameliorated by task instructions that more explicitly require processing of stimulus meaning. We recorded ERPs from 16 schizophrenia patients and 16 controls who viewed prime words each followed at 750-ms stimulus-onset asynchrony by an unrelated or related target word, or a nonword, in a non-semantic task (indicating whether a letter occurred in the target) compared to an explicit semantic task (judging prime-target relatedness). Consistent with previous work, controls exhibited greater N400 semantic priming (larger amplitude reductions for related versus unrelated targets) in the semantic task than in the orthographic task. Schizophrenia patients showed this same pattern, although their N400 semantic priming effects were smaller than controls' across tasks. Nevertheless, patients' priming effects increased as much as did controls' from the orthographic to the semantic task. Thus, connections among related concepts in schizophrenia patients' semantic memory appear grossly intact, such that, given a meaningful stimulus, they can make use of explicit cues to activate related concepts at a neurophysiological level, although their ability to do so remains less than normal. These data provide support for further research on semantic-cueing strategies for cognitive remediation of verbal memory in schizophrenia.
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Affiliation(s)
- Michael Kiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Ontario, Canada L8S 4K1
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Prévost M, Rodier M, Renoult L, Kwann Y, Dionne-Dostie E, Chapleau I, Brodeur M, Lionnet C, Debruille JB. Schizotypal traits and N400 in healthy subjects. Psychophysiology 2011; 47:1047-56. [PMID: 20456656 DOI: 10.1111/j.1469-8986.2010.01016.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We examined whether correlations previously found between symptoms of schizophrenia patients and the amplitude of an event-related potential (ERP), the N400, could be also found between schizotypal experiences of healthy subjects and the N400. We chose a semantic categorization task previously used with patients. Schizotypal experiences were measured with the schizotypal personality questionnaire (SPQ). The effects of the other factors were controlled for when assessing the correlations between each SPQ factor and N400s. These correlations were assessed at each electrode site to see whether their distribution on the scalp follows that of the N400 effect. Disorganization and interpersonal scores were found to correlate with ERPs in the N400 time window, as previously reported for the comparable symptoms of patients. However, the scalp distribution of these correlations differed from that of the N400 effect.
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Affiliation(s)
- Marie Prévost
- Douglas Mental Health University Institute, Montréal, Québec, Canada
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Prévost M, Rodier M, Lionnet C, Brodeur M, King S, Debruille JB. Paranoid induction reduces N400s of healthy subjects with delusional-like ideation. Psychophysiology 2010; 48:937-49. [DOI: 10.1111/j.1469-8986.2010.01160.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Cortical electrophysiologic event-related potentials are multidimensional measures of information processing that are well-suited for efficiently parsing automatic and controlled components of cognition that span the range of deficits evidenced in schizophrenia patients. These information processes are key cognitive measures that are recognized as informative and valid targets for understanding the neurobiology of schizophrenia. These measures may be used in concert with the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) neurocognitive measures in the development of novel treatments for schizophrenia and related neuropsychiatric disorders. The employment of novel event-related potential paradigms designed to carefully characterize the early spectrum of perceptual and cognitive information processing allows investigators to identify the neurophysiologic basis of cognitive dysfunction in schizophrenia and to examine the associated clinical and functional impairments.
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Van Petten C, Federmeier KD, Holcomb PJ. For distinguished contributions to psychophysiology: Marta Kutas. Psychophysiology 2010; 47:403-9. [DOI: 10.1111/j.1469-8986.2009.00930.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Disordered thinking in schizophrenia may be a consequence of the selection of conceptual associates of dominant meanings of ambiguous words despite contextual information suggesting subordinate meanings are more appropriate. Previous work using short sentences showed a large N400 event-related potential to subordinate meaning associates and a behavioral semantic bias, but results were variable. The current experiment used word pairs to simplify the procedure and to less tax memory maintenance. Furthermore, hemispheric responses were compared, as evidence suggests the left hemisphere may select dominant meanings, while the right hemisphere may keep all possible meanings active. Subjects indicated whether two words (CUE, TARGET) were related. The CUE, presented for 1 second, could be an ambiguous or an unambiguous noun, and the TARGET, presented 1.25 seconds after the onset of the CUE, was a dominant or subordinate associate, or a related or an unrelated word, respectively. The N400-effect was calculated from difference waveforms over 400-600 msec. Groups (23 schizophrenia, 25 matched controls) showed significantly different N400-effects to the words (group x word, p =.04). Controls showed a graded response, with dominant < subordinate < unrelated. Schizophrenia patients showed the largest N400-effect to subordinate associates, with less activity to dominant meaning associates and unrelated words. Both groups showed a right hemisphere distribution to unrelated words and substantial left hemisphere activation to subordinate associates (word x hemisphere, p <.001). These data support a semantic bias in schizophrenia. They also demonstrate a special role of the right hemisphere in maintaining broad homograph meaning hierarchies. This hemispheric specialization appears to be intact in schizophrenia.
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Affiliation(s)
- Dean F Salisbury
- Cognitive Neuroscience Laboratory, McLean Hospital, Belmont, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA
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Kuperberg GR, Kreher DA, Ditman T. What can Event-related Potentials tell us about language, and perhaps even thought, in schizophrenia? Int J Psychophysiol 2010; 75:66-76. [PMID: 19765622 PMCID: PMC3136365 DOI: 10.1016/j.ijpsycho.2009.09.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 02/05/2008] [Accepted: 02/12/2008] [Indexed: 11/18/2022]
Abstract
Disturbances of thought and language are fundamental to schizophrenia. Cognitive behavioral and electrophysiological research has implicated problems in two different neurocognitive mechanisms: abnormalities in the structure and function of semantic memory, and abnormalities in combining and integrating words together to build up sentence and discourse context. This review discusses recent electrophysiological evidence suggesting that these two deficits are not completely distinct, but rather that language impairment in schizophrenia results from a dysfunctional interaction between these systems in an effort to build up higher-order meaning. Moreover, although language abnormalities are more pronounced in patients with positive thought disorder, they manifest themselves in all patients when increased demands are placed on the comprehension system. Further investigation of language dysfunction may also provide insights into other aspects of psychotic thought.
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Affiliation(s)
- Gina R Kuperberg
- Department of Psychology, Tufts University, Medford, MA 02155, USA.
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Sitnikova T, Perrone C, Goff D, Kuperberg GR. Neurocognitive mechanisms of conceptual processing in healthy adults and patients with schizophrenia. Int J Psychophysiol 2010; 75:86-99. [PMID: 20004221 PMCID: PMC2842912 DOI: 10.1016/j.ijpsycho.2009.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/29/2009] [Accepted: 12/01/2009] [Indexed: 11/28/2022]
Abstract
This overview outlines findings of cognitive and neurocognitive studies on comprehension of verbal, pictorial, and video stimuli in healthy participants and patients with schizophrenia. We present evidence for a distinction between two complementary neurocognitive streams of conceptual analysis during comprehension. In familiar situations, adequate understanding of events may be achieved by mapping the perceived information on the associative and similarity-based connections between concepts in semantic memory - a process reflected by an N400 waveform of event-related electrophysiological potentials (ERPs). However, in less conventional contexts, a more flexible mechanism may be needed. We suggest that this alternative processing stream, reflected by a P600 ERP waveform, may use discrete, rule-like goal-related requirements of real-world actions to comprehend relationships between perceived people, objects, and actions. This neurocognitive model of comprehension is used as a basis in discussing studies in schizophrenia. These studies suggest an imbalanced engagement of the two conceptual streams in schizophrenia, whereby patients may rely on the associative and similarity-based networks in semantic memory even when it would be more adaptive to recruit mechanisms that draw upon goal-related requirements. Finally, we consider the roles that these conceptual mechanisms may play in real-life behavior, and the consequences that their dysfunction may have for disorganized behavior and inability to plan actions to achieve behavioral goals in schizophrenia.
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Rissling AJ, Light GA. Neurophysiological measures of sensory registration, stimulus discrimination, and selection in schizophrenia patients. Curr Top Behav Neurosci 2010; 4:283-309. [PMID: 21312404 DOI: 10.1007/7854_2010_59] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cortical Neurophysiological event related potentials (ERPs) are multidimensional measures of information processing that are well suited to efficiently parse automatic and controlled components of cognition that span the range of deficits exhibited in schizophrenia patients. Components following a stimulus reflect the sequence of neural processes triggered by the stimulus, beginning with early automatic sensory processes and proceeding through controlled decision and response related processes. Previous studies employing ERP paradigms have reported deficits of information processing in schizophrenia across automatic through attention dependent processes including sensory registration (N1), automatic change detection (MMN), the orienting or covert shift of attention towards novel or infrequent stimuli (P3a), and attentional allocation following successful target detection processes (P3b). These automatic and attention dependent information components are beginning to be recognized as valid targets for intervention in the context of novel treatment development for schizophrenia and related neuropsychiatric disorders. In this review, we describe three extensively studied ERP components (N1, mismatch negativity, P300) that are consistently deficient in schizophrenia patients and may serve as genetic endophenotypes and as quantitative biological markers of response outcome.
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Guerra S, Ibáñez A, Martín M, Bobes MA, Reyes A, Mendoza R, Bravo T, Domínguez M, Sosa MV. 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] [What about the content of this article? (0)] [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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Sitnikova T, Goff D, Kuperberg GR. Neurocognitive abnormalities during comprehension of real-world goal-directed behaviors in schizophrenia. J Abnorm Psychol 2009; 118:256-77. [PMID: 19413402 PMCID: PMC2819083 DOI: 10.1037/a0015619] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Origins of impaired adaptive functioning in schizophrenia remain poorly understood. Behavioral disorganization may arise from an abnormal reliance on common combinations between concepts stored in semantic memory. Avolition-apathy may be related to deficits in using goal-related requirements to flexibly plan behavior. The authors recorded event-related potentials (ERPs) in 16 patients with medicated schizophrenia and 16 healthy controls in a novel video paradigm presenting congruous or incongruous objects in real-world activities. All incongruous objects were contextually inappropriate, but the incongruous scenes varied in comprehensibility. Psychopathology was assessed with the Scales for the Assessment of Positive and Negative Symptoms (SAPS/SANS) and the Brief Psychiatric Rating Scale. In patients, an N400 ERP, thought to index activity in semantic memory, was abnormally enhanced to less comprehensible incongruous scenes, and larger N400 priming was associated with disorganization severity. A P600 ERP, which may index flexible object-action integration based on goal-related requirements, was abnormally attenuated in patients, and its smaller magnitude was associated with the SANS rating of impersistence at work or school (goal-directed behavior). Thus, distinct neurocognitive abnormalities may underlie disorganization and goal-directed behavior deficits in schizophrenia.
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Affiliation(s)
- Tatiana Sitnikova
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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Debruille JB, Renoult L. Effects of semantic matching and of semantic category on reaction time and N400 that resist numerous repetitions. Neuropsychologia 2009; 47:506-17. [DOI: 10.1016/j.neuropsychologia.2008.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 07/31/2008] [Accepted: 10/02/2008] [Indexed: 11/25/2022]
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Schumacher R, Wirth M, Perrig WJ, Strik W, Koenig T. ERP correlates of superordinate category activation. Int J Psychophysiol 2008; 72:134-44. [PMID: 19087886 DOI: 10.1016/j.ijpsycho.2008.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 11/21/2008] [Accepted: 11/21/2008] [Indexed: 11/30/2022]
Abstract
The human semantic network is hierarchically organized, containing superordinate, basic and subordinate levels. Various impairments are thought to be connected with abnormal access to superordinate concepts. We devised an ERP paradigm to examine the activation of superordinate versus otherwise related concepts in 20 healthy participants. Following the presentation of a typical category member an arrow indicated whether the appropriate superordinate category had to be generated (categorization task) or an otherwise related word (relation task). To control task execution, a second word was presented for which a match-mismatch-judgment was required. Reaction times, accuracy rates and ERPs after the second word showed that participants successfully accessed the superordinate category name and that verification in the categorization task was faster and easier than in the relation task. Comparison of ERPs after the arrow revealed topographical, Global Field Power (GFP), and onset latency differences between the two tasks and thus indicated the involvement of at least partially different neural generators. Source localization analysis confirmed that brain regions were activated that were also identified in previous experiments with semantic task. The paradigm seems to be suitable for further examination of superordinate activation processes and evaluation of impairments such as thought disorders in schizophrenic patients.
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Condray R, Yao JK, Steinhauer SR, van Kammen DP, Reddy RD, Morrow LA. Semantic memory in schizophrenia: association with cell membrane essential fatty acids. Schizophr Res 2008; 106:13-28. [PMID: 18929465 DOI: 10.1016/j.schres.2008.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 02/25/2008] [Accepted: 03/13/2008] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Semantic memory and language deficits are associated with schizophrenia. Understanding how these systems operate in this disorder will likely require a multi-factorial model that explains their linkages with cognition and modulation by dopamine. A biological factor that may provide causal convergence for these connections is cell membrane composition and dynamics. METHODS N400 is an electrophysiological measure of semantic memory and language that is sensitive to deficits in schizophrenia. Relationships among N400, cognition, dopamine, and cell membrane polyunsaturated fatty acids (PUFAs) were examined for patients tested under medicated (haloperidol only) and unmedicated (placebo) conditions. Relationships between these factors and clinical symptoms were also evaluated. The sample included 37 male schizophrenia inpatients and 34 male normal controls. The N400 priming effect was measured from visual event-related potentials recorded during a semantic priming-lexical decision task, in which semantic association (related versus unrelated words) and presentation rate (Stimulus Onset Asynchrony/SOAs: 350 and 950 ms) were varied. RESULTS N400 was associated with cognition (speed, visuoperception, attention) in patients and controls. These relationships were influenced by SOA in both groups, and by pharmacological condition in patients. Levels of total PUFAs and arachidonic acid were associated with N400 in unmedicated patients. Clinical symptoms (paranoia, thought disturbance) were associated with N400, but not with cognition or PUFAs. CONCLUSIONS Results suggest cell membrane fatty acids are associated with semantic memory and language in schizophrenia. Findings also suggest a series of linkages that are modulated by dopamine: cell membrane fatty acids are associated with N400 semantic priming; N400 semantic priming is associated with clinical symptoms.
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