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Oliver D, Chesney E, Cullen AE, Davies C, Englund A, Gifford G, Kerins S, Lalousis PA, Logeswaran Y, Merritt K, Zahid U, Crossley NA, McCutcheon RA, McGuire P, Fusar-Poli P. Exploring causal mechanisms of psychosis risk. Neurosci Biobehav Rev 2024; 162:105699. [PMID: 38710421 DOI: 10.1016/j.neubiorev.2024.105699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/17/2024] [Accepted: 04/28/2024] [Indexed: 05/08/2024]
Abstract
Robust epidemiological evidence of risk and protective factors for psychosis is essential to inform preventive interventions. Previous evidence syntheses have classified these risk and protective factors according to their strength of association with psychosis. In this critical review we appraise the distinct and overlapping mechanisms of 25 key environmental risk factors for psychosis, and link these to mechanistic pathways that may contribute to neurochemical alterations hypothesised to underlie psychotic symptoms. We then discuss the implications of our findings for future research, specifically considering interactions between factors, exploring universal and subgroup-specific factors, improving understanding of temporality and risk dynamics, standardising operationalisation and measurement of risk and protective factors, and developing preventive interventions targeting risk and protective factors.
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Affiliation(s)
- Dominic Oliver
- Department of Psychiatry, University of Oxford, Oxford, UK; NIHR Oxford Health Biomedical Research Centre, Oxford, UK; OPEN Early Detection Service, Oxford Health NHS Foundation Trust, Oxford, UK; Early Psychosis: Interventions and Clinical-Detection (EPIC) Lab, Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
| | - Edward Chesney
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Addictions Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 4 Windsor Walk, London SE5 8AF, UK
| | - Alexis E Cullen
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Clinical Neuroscience, Karolinska Institutet, Sweden
| | - Cathy Davies
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Amir Englund
- Addictions Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 4 Windsor Walk, London SE5 8AF, UK
| | - George Gifford
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Sarah Kerins
- Early Psychosis: Interventions and Clinical-Detection (EPIC) Lab, Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Paris Alexandros Lalousis
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Psychiatry and Psychotherapy, Ludwig-Maximilian-University Munich, Munich, Germany
| | - Yanakan Logeswaran
- Early Psychosis: Interventions and Clinical-Detection (EPIC) Lab, Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Biostatistics & Health Informatics, King's College London, London, UK
| | - Kate Merritt
- Division of Psychiatry, Institute of Mental Health, UCL, London, UK
| | - Uzma Zahid
- Department of Psychology, King's College London, London, UK
| | - Nicolas A Crossley
- Department of Psychiatry, University of Oxford, Oxford, UK; Department of Psychiatry, School of Medicine, Pontificia Universidad Católica de Chile, Chile
| | - Robert A McCutcheon
- Department of Psychiatry, University of Oxford, Oxford, UK; Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Oxford Health NHS Foundation Trust, Oxford, UK
| | - Philip McGuire
- Department of Psychiatry, University of Oxford, Oxford, UK; NIHR Oxford Health Biomedical Research Centre, Oxford, UK; OPEN Early Detection Service, Oxford Health NHS Foundation Trust, Oxford, UK
| | - Paolo Fusar-Poli
- Early Psychosis: Interventions and Clinical-Detection (EPIC) Lab, Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Department of Psychiatry and Psychotherapy, Ludwig-Maximilian-University Munich, Munich, Germany; Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; OASIS Service, South London and Maudsley NHS Foundation Trust, London SE11 5DL, UK
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Merchie A, Gomot M. Habituation, Adaptation and Prediction Processes in Neurodevelopmental Disorders: A Comprehensive Review. Brain Sci 2023; 13:1110. [PMID: 37509040 PMCID: PMC10377027 DOI: 10.3390/brainsci13071110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/12/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Habituation, the simplest form of learning preserved across species and evolution, is characterized by a response decrease as a stimulus is repeated. This adaptive function has been shown to be altered in some psychiatric and neurodevelopmental disorders such as autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD) or schizophrenia. At the brain level, habituation is characterized by a decrease in neural activity as a stimulation is repeated, referred to as neural adaptation. This phenomenon influences the ability to make predictions and to detect change, two processes altered in some neurodevelopmental and psychiatric disorders. In this comprehensive review, the objectives are to characterize habituation, neural adaptation, and prediction throughout typical development and in neurodevelopmental disorders; and to evaluate their implication in symptomatology, specifically in sensitivity to change or need for sameness. A summary of the different approaches to investigate adaptation will be proposed, in which we report the contribution of animal studies as well as electrophysiological studies in humans to understanding of underlying neuronal mechanisms.
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Affiliation(s)
| | - Marie Gomot
- UMR 1253 iBrain, Université de Tours, INSERM, 37000 Tours, France
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3
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Odland AU, Kristensen JL, Andreasen JT. Animal Behavior in Psychedelic Research. Pharmacol Rev 2022; 74:1176-1205. [PMID: 36180111 DOI: 10.1124/pharmrev.122.000590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/30/2022] [Indexed: 11/22/2022] Open
Abstract
Psychedelic-assisted psychotherapy holds great promise in the treatment of mental health disorders. Research into 5-hydroxytryptamine 2A receptor (5-HT2AR) agonist psychedelic compounds has increased dramatically over the past two decades. In humans, these compounds produce drastic effects on consciousness, and their therapeutic potential relates to changes in the processing of emotional, social, and self-referential information. The use of animal behavior to study psychedelics is under debate, and this review provides a critical perspective on the translational value of animal behavior studies in psychedelic research. Acute activation of 5-HT2ARs produces head twitches and unique discriminative cues, disrupts sensorimotor gating, and stimulates motor activity while inhibiting exploration in rodents. The acute treatment with psychedelics shows discrepant results in conventional rodent tests of depression-like behaviors but generally induces anxiolytic-like effects and inhibits repetitive behavior in rodents. Psychedelics impair waiting impulsivity but show discrepant effects in other tests of cognitive function. Tests of social interaction also show conflicting results. Effects on measures of time perception depend on the experimental schedule. Lasting or delayed effects of psychedelics in rodent tests related to different behavioral domains appear to be rather sensitive to changes in experimental protocols. Studying the effects of psychedelics on animal behaviors of relevance to effects on psychiatric symptoms in humans, assessing lasting effects, publishing negative findings, and relating behaviors in rodents and humans to other more translatable readouts, such as neuroplastic changes, will improve the translational value of animal behavioral studies in psychedelic research. SIGNIFICANCE STATEMENT: Psychedelics like LSD and psilocybin have received immense interest as potential new treatments of psychiatric disorders. Psychedelics change high-order consciousness in humans, and there is debate about the use of animal behavior studies to investigate these compounds. This review provides an overview of the behavioral effects of 5-HT2AR agonist psychedelics in laboratory animals and discusses the translatability of the effects in animals to effects in humans. Possible ways to improve the utility of animal behavior in psychedelic research are discussed.
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Affiliation(s)
- Anna U Odland
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jesper L Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jesper T Andreasen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
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Scaramella C, Alzagatiti JB, Creighton C, Mankatala S, Licea F, Winter GM, Emtage J, Wisnieski JR, Salazar L, Hussain A, Lee FM, Mammootty A, Mammootty N, Aldujaili A, Runnberg KA, Hernandez D, Zimmerman-Thompson T, Makwana R, Rouvere J, Tahmasebi Z, Zavradyan G, Campbell CS, Komaranchath M, Carmona J, Trevitt J, Glanzman D, Roberts AC. Bisphenol A Exposure Induces Sensory Processing Deficits in Larval Zebrafish during Neurodevelopment. eNeuro 2022; 9:ENEURO.0020-22.2022. [PMID: 35508370 PMCID: PMC9116930 DOI: 10.1523/eneuro.0020-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/10/2022] [Accepted: 04/01/2022] [Indexed: 11/21/2022] Open
Abstract
Because of their ex utero development, relatively simple nervous system, translucency, and availability of tools to investigate neural function, larval zebrafish are an exceptional model for understanding neurodevelopmental disorders and the consequences of environmental toxins. Furthermore, early in development, zebrafish larvae easily absorb chemicals from water, a significant advantage over methods required to expose developing organisms to chemical agents in utero Bisphenol A (BPA) and BPA analogs are ubiquitous environmental toxins with known molecular consequences. All humans have measurable quantities of BPA in their bodies. Most concerning, the level of BPA exposure is correlated with neurodevelopmental difficulties in people. Given the importance of understanding the health-related effects of this common toxin, we have exploited the experimental advantages of the larval zebrafish model system to investigate the behavioral and anatomic effects of BPA exposure. We discovered that BPA exposure early in development leads to deficits in the processing of sensory information, as indicated by BPA's effects on prepulse inhibition (PPI) and short-term habituation (STH) of the C-start reflex. We observed no changes in locomotion, thigmotaxis, and repetitive behaviors (circling). Despite changes in sensory processing, we detected no regional or whole-brain volume changes. Our results show that early BPA exposure can induce sensory processing deficits, as revealed by alterations in simple behaviors that are mediated by a well-defined neural circuit.
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Affiliation(s)
- Courtney Scaramella
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Joseph B Alzagatiti
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - Christopher Creighton
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Samandeep Mankatala
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Fernando Licea
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Gabriel M Winter
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Jasmine Emtage
- Department of Biology, California Institute of Technology, Pasadena, CA 91125
| | - Joseph R Wisnieski
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Luis Salazar
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Anjum Hussain
- Department of Neuroscience, University of California, Riverside, Riverside, CA 92521
| | - Faith M Lee
- Department of Society and Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Asma Mammootty
- Saint Louis University School of Medicine, St. Louis, MO 63104
| | | | - Andrew Aldujaili
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095
| | - Kristine A Runnberg
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Daniela Hernandez
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | | | - Rikhil Makwana
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Julien Rouvere
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Zahra Tahmasebi
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - Gohar Zavradyan
- Department of Neuroscience, University of California, Riverside, Riverside, CA 92521
| | | | - Meghna Komaranchath
- Department of Biomedical Engineering, Columbia University, New York, NY 10027
| | - Javier Carmona
- Department of Physics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Jennifer Trevitt
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | - David Glanzman
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
- Integrative Center for Learning and Memory, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
| | - Adam C Roberts
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
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Oliveras I, Tapias-Espinosa C, Río-Álamos C, Sampedro-Viana D, Cañete T, Sánchez-González A, Tobeña A, Fernández-Teruel A. Prepulse inhibition deficits in inbred and outbred rats and between-strain differences in startle habituation do not depend on startle reactivity levels. Behav Processes 2022; 197:104618. [DOI: 10.1016/j.beproc.2022.104618] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 02/01/2022] [Accepted: 03/03/2022] [Indexed: 12/30/2022]
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Avery SN, McHugo M, Armstrong K, Blackford JU, Woodward ND, Heckers S. Stable habituation deficits in the early stage of psychosis: a 2-year follow-up study. Transl Psychiatry 2021; 11:20. [PMID: 33414431 PMCID: PMC7791099 DOI: 10.1038/s41398-020-01167-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 01/29/2023] Open
Abstract
Neural habituation, the decrease in brain response to repeated stimuli, is a fundamental, highly conserved mechanism that acts as an essential filter for our complex sensory environment. Convergent evidence indicates neural habituation is disrupted in both early and chronic stages of schizophrenia, with deficits co-occurring in brain regions that show inhibitory dysfunction. As inhibitory deficits have been proposed to contribute to the onset and progression of illness, habituation may be an important treatment target. However, a crucial first step is clarifying whether habituation deficits progress with illness. In the present study, we measured neural habituation in 138 participants (70 early psychosis patients (<2 years of illness), 68 healthy controls), with 108 participants assessed longitudinally at both baseline and 2-year follow-up. At follow-up, all early psychosis patients met criteria for a schizophrenia spectrum disorder (i.e., schizophreniform disorder, schizophrenia, schizoaffective disorder). Habituation slopes (i.e., rate of fMRI signal change) to repeated images were computed for the anterior hippocampus, occipital cortex, and the fusiform face area. Habituation slopes were entered into a linear mixed model to test for effects of group and time by region. We found that early psychosis patients showed habituation deficits relative to healthy control participants across brain regions, and that these deficits were maintained, but did not worsen, over two years. These results suggest a stable period of habituation deficits in the early stage of schizophrenia.
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Affiliation(s)
- Suzanne N. Avery
- grid.412807.80000 0004 1936 9916Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN USA
| | - Maureen McHugo
- grid.412807.80000 0004 1936 9916Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN USA
| | - Kristan Armstrong
- grid.412807.80000 0004 1936 9916Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN USA
| | - Jennifer Urbano Blackford
- grid.412807.80000 0004 1936 9916Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN USA ,grid.413806.8Research Health Scientist, Research and Development, Department of Veterans Affairs Medical Center, Nashville, TN USA
| | - Neil D. Woodward
- grid.412807.80000 0004 1936 9916Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN USA
| | - Stephan Heckers
- grid.412807.80000 0004 1936 9916Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN USA
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Fluoxetine attenuates prepulse inhibition deficit induced by neonatal administration of MK-801 in mice. Neuroreport 2020; 31:1128-1133. [PMID: 32956214 PMCID: PMC7531495 DOI: 10.1097/wnr.0000000000001524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Increasing evidence supports schizophrenia may be a neurodevelopmental and neurodegenerative disorder. Fluoxetine, a selective serotonin reuptake inhibitor, has been reported to have neuroprotective effects and be effective in treating neurodegenerative disorders including schizophrenia. The objective of the present study was to evaluate the effect and underlying neuroprotective mechanism of fluoxetine on the sensorimotor gating deficit, a schizophrenia-like behavior in a neurodevelopmental schizophrenic mouse model induced by MK-801, an N-methyl-d-aspartate glutamate receptor antagonist. On postnatal day 7, mouse pups were treated with a total seven subcutaneous daily injections of MK-801 (1 mg/kg/day), followed by intraperitoneal injection of fluoxetine (5 or 10 mg/kg/day) starting on postnatal day 14 in the MK-801-injected mice for 4 weeks. The sensorimotor gating deficit in mice was measured by prepulse inhibition (PPI) behavioral test on postnatal day 43. After the behavioral test, the protein expression of brain-derived neurotrophic factor (BDNF) was measured by western blot or ELISA in the frontal cortex of mice. Our results showed fluoxetine attenuated PPI deficit and the decrease of cerebral BDNF expression in the MK-801-injected mice. These results suggest that fluoxetine can be used to treat sensorimotor gating deficit in a neurodevelopmental mouse model of schizophrenia, and the attenuating effect of fluoxetine on sensorimotor gating deficit may be related to fluoxetine’s neuroprotective effect targeting on the modulation of cerebral BDNF.
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Avery SN, McHugo M, Armstrong K, Blackford JU, Vandekar S, Woodward ND, Heckers S. Habituation during encoding: A new approach to the evaluation of memory deficits in schizophrenia. Schizophr Res 2020; 223:179-185. [PMID: 32736836 PMCID: PMC7704891 DOI: 10.1016/j.schres.2020.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 04/30/2020] [Accepted: 07/16/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND Memory is significantly impaired in schizophrenia. However, memory measures are often complex and confounded by additional impairments such as motivation and task comprehension, which can affect behavioral performance and obscure neural function during memory tasks. Neural signatures of memory encoding that are robust to potential confounds may shed additional light on neural deficits contributing to memory impairment in schizophrenia. METHODS Here, we investigate a potential neural signature of memory-habituation-and its relationship with healthy and impaired memory function. To limit potential confounds, we used a passive depth of encoding memory task designed to elicit neural responses associated with memory encoding while limiting other cognitive demands. To determine whether habituation during encoding was predictive of intact memory processing, we first compared neural habituation over repeated encoding exposures with subsequent explicit memory in healthy individuals. We then tested whether a similar relationship existed in patients with schizophrenia. RESULTS Explicit memory performance was impaired in patients with schizophrenia relative to healthy control subjects. In healthy participants, more habituation over repeated exposures during encoding was associated with greater repetition-related increases in accuracy during testing. However, in patients with schizophrenia, better performance was associated with less habituation, or a more sustained neural response during encoding. CONCLUSIONS These results suggest that sustained neural activity is required for normal repetition-related improvements in memory performance in schizophrenia, in line with a neural inefficiency model. Habituation may serve as a valuable index of neural processes that underlie behavioral memory performance.
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Affiliation(s)
- Suzanne N. Avery
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Maureen McHugo
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Kristan Armstrong
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Jennifer U. Blackford
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Simon Vandekar
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN
| | - Neil D. Woodward
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Stephan Heckers
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN
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He J, Zu Q, Wen C, Liu Q, You P, Li X, Wang W. Quetiapine Attenuates Schizophrenia-Like Behaviors and Demyelination in a MK-801-Induced Mouse Model of Schizophrenia. Front Psychiatry 2020; 11:843. [PMID: 32973585 PMCID: PMC7466651 DOI: 10.3389/fpsyt.2020.00843] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 08/03/2020] [Indexed: 11/13/2022] Open
Abstract
Brain demyelination is possibly one of the main pathological factors involved in schizophrenia, and targeting on myelination may be a useful strategy for schizophrenia treatment. Quetiapine, a widely used atypical antipsychotic drug for schizophrenia treatment, has been reported to have neuroprotective effects on cerebral myelination in a demyelination animal model. The objective of the present study was to evaluate the effect and underlying neuroprotective mechanism of quetiapine on the schizophrenia-like behaviors and possible cerebral demyelination induced by MK-801, an N-methyl-D-aspartate glutamate receptor antagonist. Mice were treated with chronic quetiapine (10 mg/kg/day, intraperitoneally) for 28 days. From day 22 to 28, 1 h after the administration of quetiapine, the mice were administered MK-801 (2 mg/kg/day, subcutaneously). The positive symptom of schizophrenia was measured in a locomotor activity test on day 29, the memory was evaluated by a Y-maze test on day 30, and the sensorimotor gating deficit in mice was measured by prepulse inhibition test on day 31. After the behavioral tests, the protein expression of myelin basic protein (MBP) was measured by Western Blot, and the protein expression of brain-derived neurotrophic factor (BDNF) was measured by ELISA in the frontal cortex of mice. Our results showed quetiapine attenuated schizophrenia-like behaviors including hyperactivity, memory impairment, and sensorimotor gating deficit in the MK-801 mice. In the same time, quetiapine attenuated demyelination, concurrent with attenuated BDNF decrease in the brain of MK-801-injected mice. These results suggest that the beneficial effects of quetiapine on schizophrenia might be partly related to its neuroprotective effect on brain myelin basic protein and its upregulating neuroprotective proteins such as BDNF, and indicate that modulation of cerebral demyelination could be a novel treatment target of schizophrenia.
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Affiliation(s)
- Jue He
- Department of Mental Health Research, Xiamen Xian Yue Hospital, Xiamen, China.,Institute of Neurological Disease, First Affiliated Hospital, Henan University, Kaifeng, China.,Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Qian Zu
- Institute of Neurological Disease, First Affiliated Hospital, Henan University, Kaifeng, China
| | - Chunyan Wen
- Department of Mental Health Research, Xiamen Xian Yue Hospital, Xiamen, China
| | - Qianqian Liu
- Institute of Neurological Disease, First Affiliated Hospital, Henan University, Kaifeng, China
| | - Pan You
- Department of Mental Health Research, Xiamen Xian Yue Hospital, Xiamen, China
| | - Xinmin Li
- Department of Mental Health Research, Xiamen Xian Yue Hospital, Xiamen, China.,Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Wenqiang Wang
- Department of Mental Health Research, Xiamen Xian Yue Hospital, Xiamen, China
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Mitazaki S, Nakagawasai O, Onogi H, Watanabe K, Takahashi K, Tan-No K, Quirion R, Srivastava LK, Tadano T. Role of prefrontal cortical 5-HT2A receptors and serotonin transporter in the behavioral deficits in post-pubertal rats following neonatal lesion of the ventral hippocampus. Behav Brain Res 2020; 377:112226. [DOI: 10.1016/j.bbr.2019.112226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/23/2019] [Accepted: 09/10/2019] [Indexed: 01/24/2023]
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Avery SN, McHugo M, Armstrong K, Blackford JU, Woodward ND, Heckers S. Disrupted Habituation in the Early Stage of Psychosis. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2019; 4:1004-1012. [PMID: 31445881 DOI: 10.1016/j.bpsc.2019.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/08/2019] [Accepted: 06/10/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Learning and memory are impaired in schizophrenia. Some theories have proposed that one form of memory, habituation, is particularly impaired. Preliminary evidence suggests that memory impairment is associated with failed hippocampal habituation in patients with chronic schizophrenia. We studied how abnormal habituation of the hippocampus is related to relational memory deficits in the early stage of psychosis. METHODS We measured hippocampal activity in 62 patients with early psychosis and 70 healthy individuals using functional magnetic resonance imaging. Habituation was defined as the slope of functional magnetic resonance imaging signal change to repeated presentations of faces and objects. Relational memory ability was measured as the slope of preferential viewing during a face-scene pair eye movement task outside the scanner. RESULTS Patients with early psychosis showed impaired relational memory (p < .001) and less hippocampal habituation to objects (p = .01) than healthy control subjects. In the healthy control group, better relational memory was associated with faster anterior hippocampal habituation (faces, r = -.28, p = .03). In contrast, patients with early psychosis showed no brain-behavior relationship (r = .12, p = .40). CONCLUSIONS We found evidence for disrupted hippocampal habituation in the early stage of psychosis along with an altered association between hippocampal habituation and relational memory ability. These results suggest that neural habituation may provide a novel target for early cognitive interventions in psychosis.
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Affiliation(s)
- Suzanne N Avery
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee.
| | - Maureen McHugo
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kristan Armstrong
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jennifer U Blackford
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Neil D Woodward
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Stephan Heckers
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
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12
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Berkovitch L, Del Cul A, Maheu M, Dehaene S. Impaired conscious access and abnormal attentional amplification in schizophrenia. NEUROIMAGE-CLINICAL 2018; 18:835-848. [PMID: 29876269 PMCID: PMC5988039 DOI: 10.1016/j.nicl.2018.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 11/25/2022]
Abstract
Previous research suggests that the conscious perception of a masked stimulus is impaired in schizophrenia, while unconscious bottom-up processing of the same stimulus, as assessed by subliminal priming, can be preserved. Here, we test this postulated dissociation between intact bottom-up and impaired top-down processing and evaluate its brain mechanisms using high-density recordings of event-related potentials. Sixteen patients with schizophrenia and sixteen controls were exposed to peripheral digits with various degrees of visibility, under conditions of either focused attention or distraction by another task. In the distraction condition, the brain activity evoked by masked digits was drastically reduced in both groups, but early bottom-up visual activation could still be detected and did not differ between patients and controls. By contrast, under focused top-down attention, a major impairment was observed: in patients, contrary to controls, the late non-linear ignition associated with the P3 component was reduced. Interestingly, the patients showed an essentially normal attentional amplification of the P1 and N2 components. These results suggest that some but not all top-down attentional amplification processes are impaired in schizophrenia, while bottom-up processing seems to be preserved. An elevated consciousness threshold is observed in schizophrenia. Under unattended conditions, brain activity was similarly reduced in schizophrenic patients and controls. Under attended conditions, the late ignition associated with the P3 component is impaired in patients. In schizophrenia, top-down attentional amplification is abnormal while bottom-up processing is essentially spared.
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Affiliation(s)
- L Berkovitch
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, 91191 Gif-sur-Yvette, France; Sorbonne Universités, UPMC Univ Paris 06, IFD, 4 place Jussieu, 75252 Paris Cedex 05, France.
| | - A Del Cul
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Psychiatrie d'Adultes, 75013 Paris, France; Inserm, CNRS, APHP, Institut du Cerveau et de la Moelle (ICM), Hôpital Pitié-Salpêtrière, Sorbonne Universités, UPMC Univ Paris 06, 75013 Paris, France
| | - M Maheu
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, 91191 Gif-sur-Yvette, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - S Dehaene
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, 91191 Gif-sur-Yvette, France; Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
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13
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Deficient prepulse inhibition of the startle reflex in schizophrenia using a cross-modal paradigm. Biol Psychol 2017; 128:112-116. [DOI: 10.1016/j.biopsycho.2017.07.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 02/02/2023]
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14
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Chang H, Liu J, Zhang Y, Wang F, Wu Y, Zhang L, Ai H, Chen G, Yin L. Increased central dopaminergic activity might be involved in the behavioral abnormality of cuprizone exposure mice. Behav Brain Res 2017; 331:143-150. [DOI: 10.1016/j.bbr.2017.05.045] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 05/11/2017] [Accepted: 05/17/2017] [Indexed: 11/15/2022]
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15
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McDiarmid TA, Bernardos AC, Rankin CH. Habituation is altered in neuropsychiatric disorders-A comprehensive review with recommendations for experimental design and analysis. Neurosci Biobehav Rev 2017; 80:286-305. [PMID: 28579490 DOI: 10.1016/j.neubiorev.2017.05.028] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 05/29/2017] [Indexed: 02/03/2023]
Abstract
Abnormalities in the simplest form of learning, habituation, have been reported in a variety of neuropsychiatric disorders as etiologically diverse as Autism Spectrum Disorder, Fragile X syndrome, Schizophrenia, Parkinson's Disease, Huntington's Disease, Attention Deficit Hyperactivity Disorder, Tourette's Syndrome, and Migraine. Here we provide the first comprehensive review of what is known about alterations in this form of non-associative learning in each disorder. Across several disorders, abnormal habituation is predictive of symptom severity, highlighting the clinical significance of habituation and its importance to normal cognitive function. Abnormal habituation is discussed within the greater framework of learning theory and how it may relate to disease phenotype either as a cause, symptom, or therapy. Important considerations for the design and interpretation of habituation experiments are outlined with the hope that these will aid both clinicians and basic researchers investigating how this simple form of learning is altered in disease.
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Affiliation(s)
- Troy A McDiarmid
- Graduate Program in Neuroscience, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia, V6T 1Z3, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Rm F221, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada
| | - Aram C Bernardos
- Graduate Program in Neuroscience, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia, V6T 1Z3, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Rm F221, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada
| | - Catharine H Rankin
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, British Columbia, V6T 1Z4, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Rm F221, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada.
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Matsuo J, Ota M, Hori H, Hidese S, Teraishi T, Ishida I, Hiraishi M, Kunugi H. A large single ethnicity study of prepulse inhibition in schizophrenia: Separate analysis by sex focusing on effect of symptoms. J Psychiatr Res 2016; 82:155-62. [PMID: 27505440 DOI: 10.1016/j.jpsychires.2016.07.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 07/13/2016] [Accepted: 07/29/2016] [Indexed: 10/21/2022]
Abstract
Deficits in sensorimotor gating, as measured with prepulse inhibition (PPI), have been considered an endophenotype of schizophrenia. However, the question remains whether these deficits are related to current symptoms. This single site study aimed to explore clinical features related to the modulation of startle reflex in a large sample of Japanese patients with schizophrenia (DSM-IV). The subjects comprised 181 patients and 250 healthy controls matched for age and sex. Schizophrenia symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Startle reflex to acoustic stimuli was recorded using a startle stimulus of 115 dB and a prepulse of four different conditions (intensity: 86 dB or 90 dB; lead interval: 60 ms or 120 ms). Patients exhibited significantly reduced startle magnitude (p < 0.001), habituation (p = 0.001), and PPI (90 dB, 60 ms, p = 0.016; 90 dB, 120 ms, p = 0.001) compared with controls. Patients of both sexes exhibited significantly lower habituation and PPI (90 dB, 120 ms) compared with the same sex controls. We could not detect a significant correlation with any clinical variable in the entire patients, however, when men and women were examined separately, there was a negative correlation with the PANSS cognitive domain (ρ = -0.33, p = 0.008) in men, but not in women. Moreover, when patients were subdivided into four clusters, two clusters with high positive symptoms showed significant PPI deficits in men. Our results suggest that sensorimotor gating is impaired in schizophrenia of both sexes, and PPI deficits may be related to thought disturbance and disorganization in male patients with schizophrenia.
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Affiliation(s)
- Junko Matsuo
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Miho Ota
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Hiroaki Hori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Shinsuke Hidese
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Toshiya Teraishi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Ikki Ishida
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Moeko Hiraishi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
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17
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Williams LE, Blackford JU, Luksik A, Gauthier I, Heckers S. Reduced habituation in patients with schizophrenia. Schizophr Res 2013; 151:124-32. [PMID: 24200419 PMCID: PMC3908315 DOI: 10.1016/j.schres.2013.10.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 10/11/2013] [Accepted: 10/15/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Neural habituation, the decrease in brain response to repeated stimulation, is a basic form of learning. There is strong evidence for behavioral and physiological habituation deficits in schizophrenia, and one previous study found reduced neural habituation within the hippocampus. However, it is unknown whether neural habituation deficits are specific to faces and limited to the hippocampus. Here we studied habituation of several brain regions in schizophrenia, using both face and object stimuli. Post-scan memory measures were administered to test for a link between hippocampal habituation and memory performance. METHODS During an fMRI scan, 23 patients with schizophrenia and 21 control subjects viewed blocks of a repeated neutral face or neutral object, and blocks of different neutral faces and neutral objects. Habituation in the hippocampus, primary visual cortex and fusiform face area (FFA) was compared between groups. Memory for faces, words, and word pairs was assessed after the scan. RESULTS Patients showed reduced habituation to faces in the hippocampus and primary visual cortex, but not the FFA. Healthy control subjects exhibited a pattern of hippocampal discrimination that distinguished between repeated and different images for both faces and objects, and schizophrenia patients did not. Hippocampal discrimination was positively correlated with memory for word pairs. CONCLUSION Patients with schizophrenia showed reduced habituation of the hippocampus and visual cortex, and a lack of neural discrimination between old and new images in the hippocampus. Hippocampal discrimination correlated with memory performance, suggesting reduced habituation may contribute to the memory deficits commonly observed in schizophrenia.
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Affiliation(s)
- Lisa E. Williams
- Department of Psychiatry, Vanderbilt University, 1601 23rd Ave S., Nashville, TN, 37212, USA
| | | | - Andrew Luksik
- Department of Psychiatry, Vanderbilt University, 1601 23rd Ave S., Nashville, TN, 37212, USA
| | - Isabel Gauthier
- Department of Psychology, Vanderbilt University, 2301 Vanderbilt Place, Nashville, TN, 37240, USA
| | - Stephan Heckers
- Department of Psychiatry, Vanderbilt University, 1601 23rd Ave S., Nashville, TN, 37212, USA
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Abstract
One of the oldest models of schizophrenia is based on the effects of serotonergic hallucinogens such as mescaline, psilocybin, and (+)-lysergic acid diethylamide (LSD), which act through the serotonin 5-HT(2A) receptor. These compounds produce a 'model psychosis' in normal individuals that resembles at least some of the positive symptoms of schizophrenia. Based on these similarities, and because evidence has emerged that the serotonergic system plays a role in the pathogenesis of schizophrenia in some patients, animal models relevant to schizophrenia have been developed based on hallucinogen effects. Here we review the behavioural effects of hallucinogens in four of those models, the receptor and neurochemical mechanisms for the effects and their translational relevance. Despite the difficulty of modelling hallucinogen effects in nonverbal species, animal models of schizophrenia based on hallucinogens have yielded important insights into the linkage between 5-HT and schizophrenia and have helped to identify receptor targets and interactions that could be exploited in the development of new therapeutic agents.
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19
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Michel HE, Tadros MG, Abdel-Naim AB, Khalifa AE. Prepulse inhibition (PPI) disrupting effects of Glycyrrhiza glabra extract in mice: A possible role of monoamines. Neurosci Lett 2013; 544:110-4. [DOI: 10.1016/j.neulet.2013.03.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 03/21/2013] [Accepted: 03/24/2013] [Indexed: 10/27/2022]
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Prepulse inhibition predicts working memory performance whilst startle habituation predicts spatial reference memory retention in C57BL/6 mice. Behav Brain Res 2013; 242:166-77. [DOI: 10.1016/j.bbr.2012.12.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 12/01/2012] [Accepted: 12/06/2012] [Indexed: 12/26/2022]
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21
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Myelination deficit in a phencyclidine-induced neurodevelopmental model of schizophrenia. Brain Res 2012; 1469:136-43. [PMID: 22750584 DOI: 10.1016/j.brainres.2012.06.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 05/26/2012] [Accepted: 06/02/2012] [Indexed: 01/02/2023]
Abstract
Increasing evidence supports an important role of oligodendrocytes and myelination in the pathogenesis of schizophrenia. Oligodendrocytes are the myelin-producing cells in the central nervous system. To test the myelination dysfunction hypothesis of schizophrenia, possible myelination dysfunction was evaluated in a phencyclidine (PCP)-induced neurodevelopmental model of schizophrenia. On postnatal day (PND) 2, rat pups were treated with a total 14 subcutaneous daily injections of PCP (10mg/kg) or saline. PCP-injected rats showed schizophrenia-like behaviors including hyper-locomotor activity on PND 30 and prepulse inhibition deficit on PND 31. Cerebral myelination was measured by the expression of myelin basic protein (MBP), and cerebral mature oligodendrocytes were measured by the expression of glutathione S-transferase (GST)-π in rats. The results indicate that the expressions of MBP on PND 16, 22 and 32 and GST-π on PND 22 decreased in the frontal cortex of PCP-injected rats. Our results suggest that there was myelination impairment in the phencyclidine-induced schizophrenia animal model, and indicate that myelination may play an important role in the pathogenesis of schizophrenia.
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22
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Messerotti Benvenuti S, Bianchin M, Angrilli A. Effects of simulated microgravity on brain plasticity: a startle reflex habituation study. Physiol Behav 2011; 104:503-6. [PMID: 21627974 DOI: 10.1016/j.physbeh.2011.05.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 05/11/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
There is limited but increasing evidence that space environment, namely weightless condition, may affect astronauts' cerebral neurotransmitters and cognitive performance. The present experiment hypothesized that learning and brain plasticity are affected by simulated microgravity condition. To this aim, 22 male subjects matching astronauts' characteristics were divided in two groups, Head-Down Bed Rest (HDBR) and Sitting Control. After 3-h bed rest (or sitting condition) subjects started a picture viewing task during which 30 acoustic startle probes (100 dBA loudness), divided into three consecutive blocks, were delivered through headphones while startle reflex amplitude was measured from the EMG of the orbicularis oculi muscle. Habituation analysis of the startle reflex showed a normal reflex inhibition across blocks in sitting controls and no habituation in HDBR subjects. Results point to a microgravity-induced lack of startle reflex plasticity in subjects matching astronauts, a learning deficit which may affect the success of long-term space missions.
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23
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Singer P, Boison D, Möhler H, Feldon J, Yee BK. Modulation of sensorimotor gating in prepulse inhibition by conditional brain glycine transporter 1 deletion in mice. Eur Neuropsychopharmacol 2011; 21:401-13. [PMID: 20647165 PMCID: PMC2980791 DOI: 10.1016/j.euroneuro.2010.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 06/21/2010] [Accepted: 06/23/2010] [Indexed: 01/07/2023]
Abstract
Inhibition of glycine transporter 1 (GlyT1) augments N-methyl-D-aspartate receptor (NMDAR)-mediated transmission and represents a potential antipsychotic drug target according to the NMDAR hypofunction hypothesis of schizophrenia. Preclinical evaluation of GlyT1 inhibiting drugs using the prepulse inhibition (PPI) test, however, has yielded mixed outcomes. Here, we tested for the first time the impact of two conditional knockouts of GlyT1 on PPI expression. Complete deletion of GlyT1 in the cerebral cortices confers resistance to PPI disruption induced by the NMDAR blocker MK-801 (0.2mg/kg, i.p.) without affecting PPI expression in unchallenged conditions. In contrast, restricting GlyT1 deletion to neurons in forebrain including the striatum significantly attenuated PPI, and the animals remained sensitive to the PPI-disruptive effect of MK-801 at the same dose. These results demonstrate in mice that depending on the regional and/or cell-type specificity, deletion of the GlyT1 gene could yield divergent effects on PPI.
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Affiliation(s)
- Philipp Singer
- Laboratory of Behavioural Neurobiology, Federal Institute of Technology Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland
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24
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Nakaya K, Nakagawasai O, Arai Y, Onogi H, Sato A, Niijima F, Tan-No K, Tadano T. Pharmacological characterizations of memantine-induced disruption of prepulse inhibition of the acoustic startle response in mice: Involvement of dopamine D2 and 5-HT2A receptors. Behav Brain Res 2011; 218:165-73. [DOI: 10.1016/j.bbr.2010.11.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 11/22/2010] [Accepted: 11/28/2010] [Indexed: 12/23/2022]
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25
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Ivleva EI, Morris DW, Moates AF, Suppes T, Thaker GK, Tamminga CA. Genetics and intermediate phenotypes of the schizophrenia--bipolar disorder boundary. Neurosci Biobehav Rev 2010; 34:897-921. [PMID: 19954751 DOI: 10.1016/j.neubiorev.2009.11.022] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 11/20/2009] [Accepted: 11/23/2009] [Indexed: 12/20/2022]
Abstract
Categorization of psychotic illnesses into schizophrenic and affective psychoses remains an ongoing controversy. Although Kraepelinian subtyping of psychosis was historically beneficial, modern genetic and neurophysiological studies do not support dichotomous conceptualization of psychosis. Evidence suggests that schizophrenia and bipolar disorder rather present a clinical continuum with partially overlapping symptom dimensions, neurophysiology, genetics and treatment responses. Recent large scale genetic studies have produced inconsistent findings and exposed an urgent need for re-thinking phenomenology-based approach in psychiatric research. Epidemiological, linkage and molecular genetic studies, as well as studies in intermediate phenotypes (neurocognitive, neurophysiological and anatomical imaging) in schizophrenia and bipolar disorders are reviewed in order to support a dimensional conceptualization of psychosis. Overlapping and unique genetic and intermediate phenotypic signatures of the two psychoses are comprehensively recapitulated. Alternative strategies which may be implicated into genetic research are discussed.
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Affiliation(s)
- Elena I Ivleva
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75235, USA.
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26
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Braff DL. Prepulse inhibition of the startle reflex: a window on the brain in schizophrenia. Curr Top Behav Neurosci 2010; 4:349-71. [PMID: 21312406 DOI: 10.1007/7854_2010_61] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prepulse inhibition (PPI) of the startle response is an important measure of information processing deficits and inhibitory failure in schizophrenia patients. PPI is especially useful because it occurs in the same lawful manner in all mammals, from humans to rodents, making it an ideal candidate for cross-species translational research. PPI deficits occur across the "schizophrenia spectrum" from schizophrenia patients to their clinically unaffected relatives. Parallel animal model and human brain imaging studies have demonstrated that PPI is modulated by cortico-striato-pallido-thalamic (and pontine) circuitry. This circuitry is also implicated in schizophrenia neuropathology and neurophysiology. The finding of PPI deficits in schizophrenia patients has been replicated by many groups, and these deficits correlate with measures of thought disorder and appear to be "normalized" by second generation antipsychotic (SGA) medications. Consistent pharmacological effects on PPI have been demonstrated; among these, dopamine agonists induce PPI deficits and (in animal models) these are reversed by first and SGA medications. PPI is also significantly heritable in humans and animals and can be used as a powerful endophenotype in studies of families of schizophrenia patients. Genomic regions, including the NRGL-ERBB4 complex with its glutamatergic influences, are strongly implicated in PPI deficits in schizophrenia. PPI continues to hold promise as an exciting translational cross-species measure that can be used to understand the pathophysiology and treatment of the schizophrenias via pharmacological, anatomic, and genetic studies.
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Affiliation(s)
- David L Braff
- Department of Psychiatry, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093-0804, USA.
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27
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Quednow BB, Geyer MA, Halberstadt AL. Serotonin and Schizophrenia. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1569-7339(10)70102-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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28
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Halberstadt AL, Geyer MA. Habituation and sensitization of acoustic startle: opposite influences of dopamine D1 and D2-family receptors. Neurobiol Learn Mem 2009; 92:243-8. [PMID: 18644244 PMCID: PMC2745310 DOI: 10.1016/j.nlm.2008.05.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Accepted: 05/27/2008] [Indexed: 12/01/2022]
Abstract
The startle response evoked by repeated presentation of a loud acoustic stimulus is regulated by the independent processes of sensitization and habituation. While schizophrenia is associated with information processing impairments, there is conflicting evidence regarding the existence of habituation deficits in schizophrenic patients. Recent clinical evidence, however, indicates that patients with schizophrenia display exaggerated startle sensitization and diminished habituation. Given the linkage between dopaminergic abnormalities and schizophrenia, the goal of the present investigation was to examine the effect of deleting D1 and D2-like dopamine receptors on sensitization and habituation of the acoustic startle reflex in mice. For these experiments, the acoustic startle reflex was assessed in dopamine D1, D2, and D3 receptor wild-type (WT) and knockout (KO) mice on a C57BL/6J background, using a methodology that can measure both sensitization and habituation. Mice lacking the D1 receptor gene displayed enhanced sensitization, along with a decrease in the amount of habituation that occurs in response to repetitive presentations of a startling stimulus. Conversely, the loss of the dopamine D2 or D3 receptor gene produced a sensitization deficit and a significant increase in habituation. The behavioral phenotype exhibited by D1 receptor KO mice is clearly distinct from that of the D2 and D3 receptor KO mice. The findings in D1 receptor KO mice are reminiscent of the abnormalities observed in schizophrenic patients tested in comparable startle paradigms, and indicate that D1 agonists may possess therapeutic efficacy against the information processing deficits associated with schizophrenia.
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MESH Headings
- Acoustic Stimulation
- Animals
- Disease Models, Animal
- Habituation, Psychophysiologic/physiology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D3/genetics
- Receptors, Dopamine D3/metabolism
- Reflex, Startle/physiology
- Schizophrenia/physiopathology
- Schizophrenic Psychology
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0804, USA
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29
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Abstract
It has been previously suggested that oxytocin (Oxt) may act as a natural antipsychotic. To test this hypothesis, we investigated whether disruption of the oxytocin gene (Oxt-/-) made mice more susceptible to the psychosis-related effects of amphetamine (Amp), apomorphine (Apo) and phencyclidine (PCP). We examined drug-induced changes in the prepulse inhibition (PPI) of the startle reflex, a measure of sensorimotor gating deficits characteristic of several psychiatric and neurological disorders, including schizophrenia. We found that treatment with Amp, Apo and PCP all had effects on PPI. However, in Oxt-/- mice, but not Oxt+/+ mice, PCP treatment resulted in large PPI deficits. As PCP is a noncompetitive N-methyl-D-aspartic acid receptor antagonist, these findings suggest that the absence of Oxt alters the glutamatergic component of the PPI.
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30
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Malone DT, Kearn CS, Chongue L, Mackie K, Taylor DA. Effect of social isolation on CB1 and D2 receptor and fatty acid amide hydrolase expression in rats. Neuroscience 2008; 152:265-72. [PMID: 18082330 DOI: 10.1016/j.neuroscience.2007.10.043] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 10/25/2007] [Accepted: 10/25/2007] [Indexed: 11/17/2022]
Abstract
Rearing rats in isolation has been shown to produce behavioral and neurochemical alterations similar to those observed in psychoses such as schizophrenia. Also, a dysregulation in both the endocannabinoid and dopaminergic systems has been implicated in schizophrenia. The aim of this study was to determine if there are differences in CB1 receptor and fatty acid amide hydrolase (FAAH) protein expression, as well as D2 dopamine receptor expression in different brain regions in rats reared in different environmental conditions. Twenty-one-day-old male Sprague-Dawley rats were either reared in individual cages (isolated rats) or in group cages of six per cage (group-housed rats) for 8 weeks. Quantitative fluorescence immunohistochemistry was performed on brain slices using antibodies specific to the CB1 or D2 receptor, or the enzyme FAAH. Raising rats in isolation led to a significant decrease in CB1 receptor expression in the caudate putamen and the amygdala, a significant increase in FAAH expression in the caudate putamen and the nucleus accumbens core and shell, and no significant change in D2 receptor expression in any region studied. These results indicate that the endocannabinoid system is altered in an animal model of aspects of psychosis. This implies that rearing rats under different housing conditions may provide new insight into the role of the endocannabinoid system in the development of psychoses.
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Affiliation(s)
- D T Malone
- Department of Pharmaceutical Biology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia.
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31
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Abstract
Animal models of schizophrenia may increase the understanding of the neurological abnormalities associated with the disorder and aid in the development of rational pharmacological treatments. Rather than attempting to model the entire syndrome of schizophrenia, a more biologically oriented approach to animal models has been to focus on specific symptoms of schizophrenia that are more objectively measured in the clinical population and more directly translatable to animals (e.g., observables or endophenotypes). This overview focuses on behavioral measures that have been investigated in rodent models of schizophrenia with varying degrees of predictive, etiological, and construct validity. Because of the severity of cognitive deficits in schizophrenia and their resistance to current treatments, there is a need to develop animal models specific to the cognitive symptoms of schizophrenia. In light of this need, this overview discusses rodent models of cognition with relevance to the core cognitive deficits observed in schizophrenia.
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Affiliation(s)
- Susan B Powell
- University of California, San Diego, La Jolla, California, USA
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Ducato MG, Michael GA, Thomas P, Despretz P, Monestes JL, Loas G, Boucart M. Attentional capture in schizophrenia: failure to resist interference from motion signals. Cogn Neuropsychiatry 2008; 13:185-209. [PMID: 18484287 DOI: 10.1080/13546800701706530] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Patients with schizophrenia show high susceptibility to distraction but the neural mechanisms underlying sensitivity to distraction are not clearly established. We designed a paradigm to assess whether sensitivity to distraction and dorsal stream dysfunction are related in schizophrenia. METHOD 60 patients, 37 schizotypals, and 58 healthy controls were asked to locate a target square appearing above or below fixation and to ignore a distractor that either moved abruptly (in Experiments 1 and 3) or changed in colour (in Experiment 2). The distractor condition was compared to a baseline condition with no distractor. Resistance to interference was assessed by manipulating the probability of the distractor changing more frequently (50%, 75%, 100%) on one side of fixation. RESULTS Patients, schizotypals, and controls showed attentional capture with longer response times when the distractor changed as compared to the baseline condition. In contrast to controls, the magnitude of interference from distractors remained stable for patients and schizotypals across all probability conditions and this was confined to attentional capture by motion, not by colour. CONCLUSION We found a similar pattern of results in patients and in schizotypals. Our attentional capture paradigm could help to identify early cognitive impairments in populations at risk to develop schizophrenia. The data are interpreted in terms of dysfunction of frontal control on dorsal stream functions in schizophrenia.
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Affiliation(s)
- M G Ducato
- Lab. Neurosciences fonctionnelles & pathologies, CNRS Université Lille, Lille, France
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Quednow BB. Defizite der sensomotorischen Filterleistung bei psychiatrischen Erkrankungen. ZEITSCHRIFT FUR NEUROPSYCHOLOGIE 2008. [DOI: 10.1024/1016-264x.19.3.139] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Die Präpuls-Inhibition (PPI) des akustischen Schreckreflexes gilt als operationales Maß für einen teils vorbewußten attentionalen Filterprozeß, der auch als sensomotorisches Gating bezeichnet wird. Die PPI wird durch ein cortico-striato-pallido-pontines (CSPP) Netzwerk reguliert, welches frontale und mediotemporale Hirnareale, das ventrale Striatum, das ventrale Pallidum und pontine Bereiche des Hirnstamms mit einbezieht. Verschiedene psychiatrische und neurologische Erkrankungen zeigen beeinträchtigte Gating-Prozesse, doch insbesondere die konsistenten Befunde eines PPI-Defizits in der Schizophrenie haben dazu beigetragen, daß die Schizophrenie heute auch als Filterstörung verstanden wird. Die PPI hat sich mittlerweile als translationales Modell für gestörte Filterprozesse in der Schizophrenie etabliert, da sie bei verschiedenen Versuchstieren abgeleitet werden kann und pharmakologisch manipulierbar ist. Darüber hinaus wurde die PPI als vielversprechender Endophänotyp, d. h. als Gen-naher biologischer Marker, der Schizophrenie vorgeschlagen. Man erhofft sich von der Identifizierung solcher Endophänotypen eine verbesserte Entschlüsselung der krankheitsmitverursachenden Gene im Vergleich zu bislang nicht zielführenden genetischen Assoziationsstudien mit den komplexeren Krankheitsphänotypen. Des Weiteren wird die Korrektur künstlich erzeugter PPI-Defizite bei Versuchstieren als Modell für antipsychotische Wirksamkeit neu entwickelter Substanzen zur Behandlung der Schizophrenie genutzt. Der vorliegende Artikel soll einen Überblick über die Anwendungsmöglichkeiten und Grenzen des PPI-Paradigmas in der klinischen und grundlagenorientierten psychologischen und psychiatrischen Forschung geben.
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Affiliation(s)
- Boris B. Quednow
- Neuropsychopharmakologie und Bildgebung, Psychiatrische Universitätsklinik Zürich
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Swerdlow NR, Sprock J, Braff DL. Prepulse-elicited motor reactions do not differ between schizophrenia patients and control subjects. Behav Neurosci 2006; 120:224-7. [PMID: 16492135 DOI: 10.1037/0735-7044.120.1.224] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electromyographic (EMG) measures were made of the eyeblink response to stimuli 2-16 dB over a 70-dBA noise background as well as the eyeblink response to startling 115-dBA pulses in 15 schizophrenia patients and 10 control subjects. In patients and in control subjects, weak stimuli did not elicit EMG activation. Startling stimuli elicited robust EMG activation in both groups. Compared with control subjects, schizophrenia patients are not more sensitive to motor-activating effects of weak acoustic stimuli that served as prepulses in published reports of prepulse inhibition deficits in schizophrenia. Thus, differential sensitivity to the motor-activating effects of prepulses should not contribute to reduced prepulse inhibition in schizophrenia patients versus control subjects.
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Affiliation(s)
- Neal R Swerdlow
- Department of PsychiatryUniversity of California, San Diego School of Medicine, La Jolla, CA 92093-0804, USA.
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Hsieh MH, Swerdlow NR, Braff DL. Effects of background and prepulse characteristics on prepulse inhibition and facilitation: implications for neuropsychiatric research. Biol Psychiatry 2006; 59:555-9. [PMID: 16169529 DOI: 10.1016/j.biopsych.2005.07.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 03/21/2005] [Accepted: 07/21/2005] [Indexed: 11/21/2022]
Abstract
BACKGROUND Both prepulse inhibition (PPI) and prepulse facilitation (PPF) deficits have been reported in schizophrenia patients, but the use of different experimental parameters across laboratories makes direct comparisons of results difficult. We assessed the effects of different parameters on PPI and PPF in normal subjects. METHODS Eyeblink startle was measured in 14 healthy male subjects, using 115 dB[A] white noise startle pulses and 86 dB[A] prepulses. Analyses compared the effects of: 1) background noise level (ambient 54 vs. 70 dB[A]) on PPI and PPF, 2) prepulse duration (discrete 20 msec vs. continuous) on PPF, 3) prepulse frequency (1000 Hz vs. white noise) on PPI and PPF, and 4) prepulse interval (2000 vs. 4500 msec) on PPF. RESULTS Compared to an experimentally delivered 70 dB[A] background, ambient 54 dB[A] background led to significantly more PPI (with discrete white noise prepulses), and more PPF (with continuous prepulses). Continuous and longer (4500 msec) prepulses induced more PPF than did discrete and shorter (2000 msec) prepulses. CONCLUSIONS Paradigmatic differences appear likely to be responsible for divergent findings in studies of PPI and PPF in normal and schizophrenia subjects. The present study should guide investigators in the selection of parameters for assessing PPI and PPF in studies of normal subjects and schizophrenia patients. Attention to the 4 factors of 1) background noise, 2) prepulse duration, 3) frequency, and 4) interval will facilitate comparability of results across different laboratories, especially when using PPI/PPF in schizophrenia research as neural substrate probes, as biomarkers, and as endophenotypes.
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Affiliation(s)
- Ming H Hsieh
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan
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Swerdlow NR, Geyer MA, Shoemaker JM, Light GA, Braff DL, Stevens KE, Sharp R, Breier M, Neary A, Auerbach PP. Convergence and divergence in the neurochemical regulation of prepulse inhibition of startle and N40 suppression in rats. Neuropsychopharmacology 2006; 31:506-15. [PMID: 16123772 PMCID: PMC1373667 DOI: 10.1038/sj.npp.1300841] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prepulse inhibition of startle ('PPI'), a cross-species measure of sensorimotor gating, is impaired in schizophrenia patients. Suppression of P50 event-related potentials (ERPs) in response to the second of two clicks ('P50 gating') is also impaired in schizophrenia. Suppression of N40 ERPs to the second of two clicks ('N40 gating') is thought by some to be a rat homolog of human P50 gating. Emerging evidence suggests differences in the neurobiology of deficits detected by PPI vs P50 (or N40) gating. We recorded PPI and N40 gating contemporaneously in rats, to assess convergence and divergence in the neurochemical regulation of these measures. Dose-response studies examined the effects of apomorphine (APO), phencyclidine (PCP) or the 5HT2A agonist DOI on PPI, and on motor responses to stimuli (S1 and S2) that elicit N40 gating. Effects of optimal drug doses on PPI and N40 gating were then assessed in other rats with implanted cortical surface electrodes. APO, PCP and DOI caused dose-dependent disruptions of both PPI and gating of motor responses to N40 stimuli. Reduced PPI reflected diminished prepulse effectiveness, demonstrated by increased startle levels on prepulse+pulse trials. In contrast, reduced gating of motor responses to N40 stimuli reflected a reduced motor response to S1. In separate rats, robust PPI, N40 potentials and N40 gating could be detected within one test. PPI and N40 gating were disrupted by APO, PCP, and DOI. Again, drug effects on PPI reflected increased startle on prepulse+pulse trials, while those on N40 gating reflected reduced ERP responses to S1. In conclusion, when PPI and N40 gating were studied concurrently in rats, drug effects on PPI reflected reduced inhibition of startle by the prepulse, while diminished N40 gating reflected S1 response suppression. Despite similarities in drug sensitivity, these results suggest that distinct neurobiological mechanisms underlie drug-induced deficits in PPI and N40 gating.
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Affiliation(s)
- Neal R Swerdlow
- Department of Psychiatry, UCSD School of Medicine, La Jolla, CA 92093-0804, USA.
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Petryshen TL, Kirby A, Hammer RP, Purcell S, O'Leary SB, Singer JB, Hill AE, Nadeau JH, Daly MJ, Sklar P. Two quantitative trait loci for prepulse inhibition of startle identified on mouse chromosome 16 using chromosome substitution strains. Genetics 2005; 171:1895-904. [PMID: 15998716 PMCID: PMC1456091 DOI: 10.1534/genetics.105.045658] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 06/28/2005] [Indexed: 11/18/2022] Open
Abstract
Prepulse inhibition (PPI) of acoustic startle is a genetically complex quantitative phenotype of considerable medical interest due to its impairment in psychiatric disorders such as schizophrenia. To identify quantitative trait loci (QTL) involved in mouse PPI, we studied mouse chromosome substitution strains (CSS) that each carry a homologous chromosome pair from the A/J inbred strain on a host C57BL/6J inbred strain background. We determined that the chromosome 16 substitution strain has elevated PPI compared to C57BL/6J (P = 1.6 x 10(-11)), indicating that chromosome 16 carries one or more PPI genes. QTL mapping using 87 F(2) intercross progeny identified two significant chromosome 16 loci with LODs of 3.9 and 4.7 (significance threshold LOD is 2.3). The QTL were each highly significant independently and do not appear to interact. Sequence variation between B6 and A/J was used to identify strong candidate genes in the QTL regions, some of which have known neuronal functions. In conclusion, we used mouse CSS to rapidly and efficiently identify two significant QTL for PPI on mouse chromosome 16. The regions contain a limited number of strong biological candidate genes that are potential risk genes for psychiatric disorders in which patients have PPI impairments.
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Affiliation(s)
- Tracey L Petryshen
- Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Broad Institute of Harvard, 185 Cambridge Street, Cambridge, MA 02139, USA
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Cilia J, Cluderay JE, Robbins MJ, Reavill C, Southam E, Kew JNC, Jones DNC. Reversal of isolation-rearing-induced PPI deficits by an alpha7 nicotinic receptor agonist. Psychopharmacology (Berl) 2005; 182:214-9. [PMID: 16001118 DOI: 10.1007/s00213-005-0069-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Accepted: 05/09/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE The alpha7 subtype of the nicotinic receptor plays an important role in auditory sensory gating. Schizophrenics show deficient sensory gating and abnormalities in the number and regulation of nicotinic receptors. Prepulse inhibition (PPI) deficits exhibited by isolation-reared rats are thought to model the sensorimotor gating deficits seen in schizophrenia. OBJECTIVE To examine the role of nicotinic alpha7 receptors in the isolation-rearing rat model, we tested whether the selective alpha7 receptor agonist (R)-N-(1-Azabicyclo[2.2.2]oct-3-yl)(5-(2-pyridyl)thiophene-2-carboxamide) (compound A) could reverse isolation-rearing-induced PPI deficits, and investigated alpha7 receptor RNA expression in the hippocampus, prefrontal cortex, cerebellum, nucleus accumbens and thalamus, and alpha7 receptor protein expression in the hippocampus of isolation- and group-reared rats. METHOD Rats reared in isolation or groups of five from weaning were tested in the PPI paradigm under conditions of variable inter-stimulus interval (ISI) (pulse = 110 dB/50 ms; prepulse = 75 dB/30 ms; ISI = 30, 100 and 300 ms) 30 min following administration of compound A (3.2-10 mg/kg i.p.). Alpha7 receptor expression was measured by TaqMan RT-PCR (total RNA) and autoradiography (protein). RESULTS Isolation-rearing-induced PPI deficits were attenuated by both doses of compound A at 100-ms ISI and by 10 mg/kg at 300-ms ISI. Expression of alpha7 receptor RNA and protein was unaltered in isolation-reared rats. CONCLUSION Although altered alpha7 receptor expression may not underlie the phenotype of isolation-reared rats, the activation of these receptors may be of benefit in re-establishing efficient gating function.
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Affiliation(s)
- Jackie Cilia
- Psychiatry CEDD, GlaxoSmithKline, Third Avenue, Harlow, CM19 5AW, UK.
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Malone DT, Taylor DA. The effect of Delta9-tetrahydrocannabinol on sensorimotor gating in socially isolated rats. Behav Brain Res 2005; 166:101-9. [PMID: 16143410 DOI: 10.1016/j.bbr.2005.07.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 07/19/2005] [Accepted: 07/20/2005] [Indexed: 11/24/2022]
Abstract
Rearing rats in isolation produces behavioural and neurochemical alterations similar to those observed in schizophrenia. Cannabinoids have also been implicated in inducing psychotic symptoms. In this study, we investigate the effect of the major psychoactive constituent of cannabis and partial cannabinoid CB(1) receptor agonist Delta(9)-tetrahydrocannabinol (THC) on prepulse inhibition (%PPI) of the acoustic startle reflex and on habituation in socially isolated and grouped rats. Deficits in %PPI are reminiscent of sensorimotor gating deficits observed in psychoses. Male Sprague-Dawley rat pups (21 days old) were housed in either single cages (isolated) or in group cages of six per cage (grouped). Eight weeks later the effect of vehicle, THC and the CB(1) receptor antagonist SR 141716 on %PPI was tested. Vehicle treated isolated rats exhibited significantly reduced PPI compared with grouped rats. Isolated rats treated with THC had significantly lower %PPI than vehicle treated groups. This further decrease of %PPI by THC was reversed by pre-treatment with SR 141716, indicating that this effect was mediated by CB(1) receptors. THC had no significant effect on %PPI in grouped rats. SR 141716 had no significant effect on %PPI in either grouped or isolated rats. Habituation did not significantly alter in any treatment group in any treatment group. These results suggest that THC produces significant decreases in sensorimotor gating in rats with already dysfunctional sensorimotor gating processes, but not in normal rats. The lack of effect of SR 141716 in either grouped or isolated rats suggests that normal endocannabinoid function is not critical in sensorimotor gating processes.
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Affiliation(s)
- Daniel Thomas Malone
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, Parkville 3052, Vic., Australia.
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Cilia J, Hatcher PD, Reavill C, Jones DNC. Long-term evaluation of isolation-rearing induced prepulse inhibition deficits in rats: an update. Psychopharmacology (Berl) 2005; 180:57-62. [PMID: 15650841 DOI: 10.1007/s00213-004-2139-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Accepted: 11/22/2004] [Indexed: 11/28/2022]
Abstract
RATIONALE Rats reared in social isolation from weaning show prepulse inhibition (PPI) deficits which are thought to model the sensorimotor gating deficits seen in schizophrenia and other psychiatric disorders. We have previously reported that ten cohorts of Lister Hooded rats reared in isolation showed robust and reliable PPI deficits. OBJECTIVE Our methodology differed from those used by others (Weiss and Feldon in Psychopharmacology 156(2-3):305-326, 2001), most notably in the weaning of pups at postnatal day (PND) 28 compared with PND20-22. Since our initial report, we have studied 18 more cohorts weaned at PND28 and one cohort weaned at PND21. METHOD At weaning, male Lister Hooded pups were singly (isolates) or group (n=5) housed (grouped). Eight weeks later, startle and PPI responses of isolates and grouped rats were investigated using conditions of fixed inter-stimulus interval (ISI) (pulse=110 dB/50 ms; prepulse (PP)=75-80 dB/30 ms; ISI=100 ms). RESULTS Isolates from 14 of the subsequent 18 cohorts demonstrated PPI deficits, giving an overall success rate of 86% for all 28 cohorts. %PPI ranged from 12 to 26% in the isolates and from 26 to 47% in the grouped for the successful cohorts, compared to 16-30% (isolates) and 19-35% (grouped) for those that failed. Only five out of the 19 subsequent cohorts demonstrated startle hyperreactivity, which was unrelated to PPI response. The isolates from the cohort weaned at PND21 did not show a significant deficit in PPI, suggesting, in our hands at least, a requirement for weaning at PND28. CONCLUSION The data presented here reinforce our original findings that isolation-rearing of Lister Hooded rats provides a viable, non-pharmacological model of impaired PPI.
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Affiliation(s)
- J Cilia
- Psychiatry CEDD, GlaxoSmithKline plc, New Frontiers Science Park, Third Avenue, Harlow, Essex, UK CM19 5AW.
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Hoenig K, Hochrein A, Quednow BB, Maier W, Wagner M. Impaired prepulse inhibition of acoustic startle in obsessive-compulsive disorder. Biol Psychiatry 2005; 57:1153-8. [PMID: 15866555 DOI: 10.1016/j.biopsych.2005.01.040] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 11/18/2004] [Accepted: 01/23/2005] [Indexed: 12/01/2022]
Abstract
BACKGROUND Animal and clinical studies suggest that impaired sensorimotor gating, as assessed with the prepulse inhibition (PPI) paradigm, may result from dysfunctional frontostriatal brain circuits and from neurochemical alterations which are also implied in the pathophysiology of obsessive-compulsive disorder (OCD). However, there is only preliminary evidence about impaired PPI in OCD so far. METHODS Acoustic PPI was measured in 30 OCD patients and 30 matched healthy controls with a paradigm using different prepulse intensities. Psychopathology assessment included ratings for obsessions, compulsions, and depression. RESULTS PPI was reduced in OCD patients, and this deficit was most pronounced for most intense (16 dB(A)) prepulses, where mean PPI was 39.6% in unmedicated patients (n = 4), 45.8% in medicated patients, and 58.9% in controls. No group differences were observed with regard to the habituation of acoustic startle magnitude. Startle measures were generally not associated with clinical measures, although such associations may have been obscured by medication effects. CONCLUSIONS The present study confirms deficient central inhibitory functioning in patients with OCD and supports the model of deficient frontostriatal circuits in OCD. The relationship of PPI deficits to pharmacological and behavioral treatment and to possible subtypes of OCD merits further study.
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Affiliation(s)
- Klaus Hoenig
- Department of Psychiatry, University of Bonn, Bonn, Germany.
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Braff DL, Light GA, Ellwanger J, Sprock J, Swerdlow NR. Female schizophrenia patients have prepulse inhibition deficits. Biol Psychiatry 2005; 57:817-20. [PMID: 15820241 DOI: 10.1016/j.biopsych.2004.12.030] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 11/30/2004] [Accepted: 12/15/2004] [Indexed: 11/18/2022]
Abstract
BACKGROUND Prepulse inhibition (PPI) of startle shows sexual dimorphism: women have lower levels of PPI than do men, and have menstrual cycle shifts in PPI. Many studies report PPI deficits in male schizophrenia patients; one recent report identified PPI deficits in male but not female patients. This study was designed to determine whether female schizophrenia patients have lower levels of PPI than normal females. METHODS Twenty-five female schizophrenia patients, and 26 normal females were tested in a startle paradigm using 115 dB startle pulses and prepulses of 8 and 16 dB above a 70 dB background, with 30 and 120 msec prepulse intervals. RESULTS Female patients had significantly less PPI compared with normal females, particularly when 16 dB prepulses were utilized. Patients also exhibited a nonsignificant trend towards lower levels of habituation compared to normal subjects. CONCLUSIONS Under the present paradigmatic and subject acquisition conditions, female schizophrenia patients had PPI deficits compared to normal females.
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Affiliation(s)
- David L Braff
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0804, USA.
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Aasen I, Kolli L, Kumari V. Sex effects in prepulse inhibition and facilitation of the acoustic startle response: implications for pharmacological and treatment studies. J Psychopharmacol 2005; 19:39-45. [PMID: 15671127 DOI: 10.1177/0269881105048890] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Prepulse inhibition (PPI) refers to the reduction in the response amplitude to a startling stimuli (pulse) if it is preceded (i.e. 30-500 ms) by a weak stimulus (prepulse). If the time interval between the prepulse and pulse is more than 500 ms, then an increase in this response amplitude can be seen, termed prepulse facilitation (PPF). PPI is thought to represent an operational index of sensorimotor function whereas PPF is thought to reflect, at least to some degree, sustained attention. Interestingly, PPI is found to be sexually dimorphic, with men exhibiting more PPI than women when subjects are tested without regard to where they are in the menstrual cycle, and to be impaired in several neuropsychiatric disorders known to exhibit sex differences in their clinical presentation. PPF has received relatively less attention in both normal and clinical studies. This study examined sex differences in both PPI and PPF in 62 healthy subjects (34 women, 28 men) using a range of prepulse-to-pulse intervals to elicit PPI (30, 60, 120, 240 and 480 ms) and PPF (1000 and 2000 ms). Men showed higher PPI than women but women showed higher PPF compared to men. These results suggest that reduced PPI in healthy women is not a simple reduction but rather a shift of the inhibition/facilitation curve in the direction of facilitation in women, relative to men. Future studies investigating pharmacological and treatment effects using a prepulse modification paradigm in normal and clinical populations of both sexes would benefit from an examination of sex effects and assessments of both PPI and PPF.
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Affiliation(s)
- Ingrid Aasen
- Department of Psychology, Division of Psychological Medicine, Institute of Psychiatry, London, UK.
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Swerdlow NR, Kuczenski R, Goins JC, Crain SK, Ma LT, Bongiovanni MJ, Shoemaker JM. Neurochemical analysis of rat strain differences in the startle gating-disruptive effects of dopamine agonists. Pharmacol Biochem Behav 2004; 80:203-11. [PMID: 15680173 DOI: 10.1016/j.pbb.2004.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 10/18/2004] [Accepted: 11/08/2004] [Indexed: 11/20/2022]
Abstract
The disruption of prepulse inhibition (PPI) in rats by dopamine (DA) agonists is used to study the neural basis of strain differences in dopaminergic function. We reported that, compared to Long-Evans (LEH) rats, Sprague-Dawley (SDH) rats are more sensitive to the PPI-disruptive effects of the direct D1/D2 agonist apomorphine (APO) and the indirect DA agonist d-amphetamine (AMPH). This strain difference is heritable, with PPI drug sensitivity following a generational pattern (SDH>N2>F1>LEH) suggestive of additive effects of multiple genes. Here, we assessed the neurochemical bases for these heritable strain differences by measuring tissue levels of dopamine, serotonin (5HT) and their respective metabolites in several forebrain regions after vehicle, APO or AMPH administration. SDH rats were more sensitive than LEH rats to the PPI-disruptive effects of both APO (0.5 mg/kg) and AMPH (4.5 mg/kg). Several significant SDH vs. LEH strain differences in regional neurochemical levels were detected, as were drug effects on these chemicals. However, SDH, LEH and F1 rats did not exhibit differential drug sensitivity in any neurochemical indices measures. These findings suggest that inherited differences in the dopaminergic regulation of sensorimotor gating do not likely reflect differences in presynaptic forebrain dopaminergic or serotonergic processes.
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Affiliation(s)
- Neal R Swerdlow
- Department of Psychiatry, UCSD School of Medicine, 9500 Gilman Dr., La Jolla, CA 92037-0804, USA.
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Malone DT, Long LE, Taylor DA. The effect of SR 141716 and apomorphine on sensorimotor gating in Swiss mice. Pharmacol Biochem Behav 2004; 77:839-45. [PMID: 15099930 DOI: 10.1016/j.pbb.2004.02.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2003] [Revised: 02/16/2004] [Accepted: 02/23/2004] [Indexed: 10/26/2022]
Abstract
The aim of the present study was to investigate in Swiss mice the acute effects of the CB(1) receptor antagonist N-piperidino-5-(4-chlorphenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (SR 141716) alone and in combination with apomorphine, a D(1)/D(2) receptor agonist, on prepulse inhibition (PPI) of the acoustic startle response, an operational measure of sensorimotor gating. SR 141716 (1 and 3 mg/kg i.p.) had no significant effect on PPI. Apomorphine (3 mg/kg i.p.) significantly disrupted PPI. The PPI of mice injected with SR 141716 (1 mg/kg i.p.) plus apomorphine (3 mg/kg i.p.) was not significantly different to that of vehicle plus apomorphine (3 mg/kg i.p.)-treated mice. However, the higher dose of SR 141716 used (3 mg/kg i.p.) significantly inhibited the disruption of PPI produced by apomorphine. These results suggest that antagonism of CB(1) receptors with SR 141716 has no significant effect on sensorimotor gating in Swiss mice. However, CB(1) receptors appear to be important in the effect of apomorphine on sensorimotor gating, as antagonism of CB(1) receptors with SR 141716 inhibits apomorphine-induced disruptions.
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Affiliation(s)
- Daniel T Malone
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia.
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Abstract
Recent years have seen a dramatic growth in the number of studies using prepulse inhibition (PPI) paradigms to index information processing deficits in schizophrenia. There are, however, robust sex differences in PPI in healthy subjects, with women exhibiting less PPI than men in the absence of any psychopathology. To investigate the role of sex in prepulse modification deficits in the long-term course of schizophrenia, we assessed PPI (response inhibition with the prepulse preceding the pulse by 30-150 ms) and prepulse facilitation (PPF; response facilitation with the prepulse preceding the pulse by 1000 ms) of the acoustic startle response in 42 chronic schizophrenia patients (27 men; all 42 on typical antipsychotics) and 35 controls (15 men). The results revealed that healthy women showed less PPI than healthy men. Men with schizophrenia showed less PPI compared to healthy men, but women with schizophrenia did not differ in PPI from healthy women. Age of illness onset negatively correlated to PPI in male patients. There was no significant effect of sex in PPF, and although patients (regardless of sex) showed less PPF relative to controls, this effect was abolished when the current age was co-varied for. These findings indicate sex differences in PPI deficits in schizophrenia. Future studies of schizophrenia patients need to take sex and age of subjects into account to optimise the investigation of PPI deficits, and their clinical, neural, and pharmacological correlates.
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Affiliation(s)
- Veena Kumari
- Department of Psychology Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
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47
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Braff DL, Light GA. Preattentional and attentional cognitive deficits as targets for treating schizophrenia. Psychopharmacology (Berl) 2004; 174:75-85. [PMID: 15118804 DOI: 10.1007/s00213-004-1848-0] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Accepted: 01/24/2004] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND RATIONALE Pharmacotherapy of schizophrenia has traditionally targeted positive psychotic symptoms. An emerging view is that developing medications that improve cognition in schizophrenia patients is a major step forward in achieving better functional outcome. The cognitive deficits that are often observed in schizophrenia can be assessed using (1) neuropsychological tests; and (2) neurophysiological tests, the topic of this article. These neurophysiological measures cover a spectrum from automatic preattentional to attention-dependent processes. OBJECTIVES This article focuses on cognitive deficits that appear to be promising targets for a new "third generation" of medications that may be used to treat schizophrenia and other patients with specific deficits in cognition and functioning. We discuss the possible use of the following six measures of preattentional and attention-dependent cognitive deficits: mismatch negativity, P50 event-related potential suppression, prepulse inhibition of the startle response, P300 event-related potential, continuous performance task performance, and oculomotor antisaccade performance. CONCLUSIONS The use of preattentional and attention-dependent measures offer unique opportunities to improve our armamentarium of pharmacologic strategies for the treatment of cognitive deficits in schizophrenia patients. This review illustrates the usefulness of these measures as targets for existing and new antipsychotic medications that will potentially (1) characterize the cognitive deficits that occur in schizophrenia patients and (2) assess medication-related improvement on these measures and the potential associated improvement in functional outcome.
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Affiliation(s)
- David L Braff
- Department of Psychiatry, Medical Center, University of California, 200 West Arbor Drive, San Diego, CA 92103-8816, USA.
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Meincke U, Light GA, Geyer MA, Braff DL, Gouzoulis-Mayfrank E. Sensitization and habituation of the acoustic startle reflex in patients with schizophrenia. Psychiatry Res 2004; 126:51-61. [PMID: 15081627 DOI: 10.1016/j.psychres.2004.01.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2003] [Revised: 01/07/2004] [Accepted: 01/12/2004] [Indexed: 10/26/2022]
Abstract
Assessments of prepulse inhibition and habituation of the acoustic startle response have proved to be valuable tools for assessing deficits of sensorimotor gating and information processing in schizophrenia patients. Recent studies, however, have reported inconsistent results regarding startle habituation deficits in schizophrenia using block-to-block analyses. Some of these inconsistencies may be due to abnormal initial sensitization effects to startle-eliciting stimuli. In a longitudinal study during the course of an acute psychotic episode, 34 medicated inpatients were examined with regard to sensitization and habituation effects in a trial-by-trial analysis and compared with 18 normal control subjects. On two examinations--10 days after admission and after psychopathological improvement 2-3 weeks later--schizophrenia patients exhibited an exaggerated magnitude increment across the first few startle-eliciting stimuli and habituation deficits that were evident when the effect of sensitization was removed from analysis. In the present study, both increased sensitization and reduced habituation appeared to be trait markers of schizophrenic psychoses. The enhanced sensitization effect--presumably due to an abnormal arousal modulation--reflects abnormal stimulus processing in schizophrenia, i.e. the diminished ability to learn the irrelevance of simple identical stimuli. In addition, the present data have important implications for designing startle studies to assess sensitization, habituation and prepulse inhibition in one session.
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Affiliation(s)
- Ulrich Meincke
- Department of Psychiatry and Psychotherapy, Technical University of Aachen, Pauwelsstrasse 30, D-52057 Aachen, Germany.
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49
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Swerdlow NR, Shoemaker JM, Noh HR, Ma L, Gaudet I, Munson M, Crain S, Auerbach PP. The ventral hippocampal regulation of prepulse inhibition and its disruption by apomorphine in rats are not mediated via the fornix. Neuroscience 2004; 123:675-85. [PMID: 14706779 DOI: 10.1016/j.neuroscience.2003.08.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prepulse inhibition (PPI) of startle is a measure of sensorimotor gating that is impaired in schizophrenia. We have reported that PPI is regulated by the ventral hippocampus (VH) and that the PPI disruptive effects of the dopamine agonist apomorphine are enhanced 4 weeks after excitotoxic lesions of the VH. The mechanisms responsible for the VH influence on PPI are not understood, but have been ascribed to interactions between the VH and nucleus accumbens. In the present study, we examined whether the VH influence on PPI and its dopaminergic regulation is dependent on the integrity of the VH-accumbens projection via the fornix. First, the PPI-disruptive effects of intra-VH NMDA infusion were assessed after sham or electrolytic transection of the fornix. Second, the PPI-disruptive effects of apomorphine were assessed 1 month after excitotoxic or electrolytic lesions of the VH, or after fornix transection. Intra-VH N-methyl-D-aspartate infusion significantly disrupted PPI; this effect was unaffected by fornix lesions. The PPI-disruptive effects of apomorphine were significantly enhanced by excitotoxic or electrolytic lesions of the VH, but not by fornix transection. The influence of the VH on PPI and its dopaminergic regulation does not appear to be mediated via the fornix. The enhanced sensitivity to the PPI-disruptive effects of apomorphine after VH lesions is not dependent on excitotoxin-induced changes in the VH or its downstream projections.
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Affiliation(s)
- N R Swerdlow
- UCSD Department of Psychiatry, 9500 Gilman Drive, 92037-0804, La Jolla, CA, USA.
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50
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Duncan E, Szilagyi S, Schwartz M, Kunzova A, Negi S, Efferen T, Peselow E, Chakravorty S, Stephanides M, Harmon J, Bugarski-Kirola D, Gonzenbach S, Rotrosen J. Prepulse inhibition of acoustic startle in subjects with schizophrenia treated with olanzapine or haloperidol. Psychiatry Res 2003; 120:1-12. [PMID: 14500109 DOI: 10.1016/s0165-1781(03)00161-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies of the acoustic startle response and of its inhibition by the presentation of a non-startling preliminary stimulus (prepulse inhibition, PPI) have revealed deficits in PPI in schizophrenic subjects compared to healthy controls. Animal studies indicate that atypical antipsychotics improve PPI deficits induced by NMDA antagonists more consistently than typical antipsychotics. The effect of medication status on PPI in schizophrenia is unresolved in the literature. In the current study the effects on PPI of the atypical antipsychotic olanzapine and the typical antipsychotic haloperidol were compared to the unmedicated state in subjects with schizophrenia. In a between-group design, 11 schizophrenic subjects on olanzapine, 16 subjects on haloperidol, and 14 subjects who were on no medication received acoustic startle testing with PPI determination. ANOVAs revealed no significant differences in startle to pulse alone stimuli, habituation of startle, or PPI between the olanzapine, haloperidol and unmedicated groups. These 41 subjects with schizophrenia were compared to a group of 21 historical healthy controls and found to have reduced PPI. These data do not indicate a preferential effect of olanzapine compared to haloperidol on sensorimotor gating in schizophrenia. The results are consistent with the hypothesis that PPI impairments are relatively stable across treatment conditions.
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Affiliation(s)
- Erica Duncan
- Emory University School of Medicine, GA, Atlanta, USA.
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