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Ekin M, Akdal G, Bora E. Antisaccade error rates in first-episode psychosis, ultra-high risk for psychosis and unaffected relatives of schizophrenia: A systematic review and meta-analysis. Schizophr Res 2024; 266:41-49. [PMID: 38367611 DOI: 10.1016/j.schres.2024.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 05/05/2023] [Accepted: 02/13/2024] [Indexed: 02/19/2024]
Abstract
BACKGROUND Antisaccade, which is described as looking at the opposite location of the target, is an eye movements paradigm used for assessing cognitive functions in schizophrenia. Initiation and sustainment of saccades in antisaccade are managed by frontal and parietal cortical areas. Antisaccade abnormalities are well-established findings in schizophrenia. However, studies in the early phases of psychotic disorders and clinical/familial risk for psychosis reported inconsistent findings. The current systematic review aimed to review the results of studies investigating antisaccade error rates in first-episode psychosis (FEP), individuals with ultra-high-risk for psychosis (UHRP), and familial-high-risk for psychosis (FHRP) compared to healthy controls. METHOD A meta-analysis of 17 studies was conducted to quantitatively review antisaccade errors in FEP, UHR-P and FHRP. The error rate (Hedges'g) was compared between the total of 860 FEP, UHRP, FHRP, and 817 healthy controls. Hedges' g for effect size, I2 for estimating the percentage of variability, and publication bias were evaluated through the R software. RESULTS The outcomes of this meta-analysis suggested that FEP is associated with a robust deficit in the antisaccade error rate (g = 1.16, CI = 0.95-1.38). Additionally, both the clinical and familial high-risk groups showed small but significant increases in AS errors (g = 0.26, CI = 0.02-0.52 and g = 0.34, CI = 0.13-0.55, respectively). CONCLUSION The large effect size estimated for FEP was compatible with previously reported results in chronic schizophrenia patients. Additionally, relatives had abnormalities with small to medium effect sizes and significant differences. The current findings suggest that antisaccade errors might be a potential endophenotype for psychotic disorders.
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Affiliation(s)
- Merve Ekin
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, Izmir, Turkey; Institude of Psychology, SWPS University, Warsaw, Poland.
| | - Gülden Akdal
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, Izmir, Turkey; Department of Neurology, Faculty of Medicine, Dokuz Eylül University, Izmir, Turkey.
| | - Emre Bora
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, Izmir, Turkey; Department of Psychiatry, Faculty of Medicine, Dokuz Eylül University, Izmir, Turkey; Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne, Victoria, Australia.
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Lehet M, Rolfs M, Bao J, Fattal J, Thakkar KN. Pre-saccadic shifts of attention in individuals diagnosed with schizophrenia. Brain Behav 2024; 14:e3466. [PMID: 38450916 PMCID: PMC10918725 DOI: 10.1002/brb3.3466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 03/08/2024] Open
Abstract
INTRODUCTION Pathophysiological theories of schizophrenia (SZ) symptoms posit an abnormality in using predictions to guide behavior. One such prediction is based on imminent movements, via corollary discharge signals (CD) that relay information about planned movement kinematics to sensory brain regions. Empirical evidence suggests a reduced influence of sensorimotor predictions in individuals with SZ within multiple sensory systems, including in the visual system. One function of CD in the visual system is to selectively enhance visual sensitivity at the location of planned eye movements (pre-saccadic attention), thus enabling a prediction of the to-be-foveated stimulus. We expected pre-saccadic attention shifts to be less pronounced in individuals with SZ than in healthy controls (HC), resulting in unexpected sensory consequences of eye movements, which may relate to symptoms than can be explained in the context of altered allocation of attention. METHODS We examined this question by testing 30 SZ and 30 HC on a pre-saccadic attention task. On each trial participants made a saccade to a cued location in an array of four stimuli. A discrimination target that was either congruent or incongruent with the cued location was briefly presented after the cue, during saccade preparation. Pre-saccadic attention was quantified by comparing accuracy on congruent trials to incongruent trials within the interval preceding the saccade. RESULTS Although SZs were less accurate overall, the magnitude of the pre-saccadic attention effect generally did not differ across groups nor show a convincing relationship with symptom severity. We did, however, observe that SZ had reduced pre-saccadic attention effects when the discrimination target (probe) was presented at early stages of saccade planning, when pre-saccadic attention effects first emerged in HC. CONCLUSION These findings suggest generally intact pre-saccadic shifts of attention in SZ, albeit slightly delayed. Results contribute to our understanding of altered sensory predictions in people with schizophrenia.
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Affiliation(s)
- Matthew Lehet
- Department of PsychologyMichigan State UniversityEast LansingMichiganUSA
| | - Martin Rolfs
- Department of PsychologyHumboldt UniversityBerlinGermany
| | - Jacqueline Bao
- Department of PsychologyMichigan State UniversityEast LansingMichiganUSA
| | - Jessica Fattal
- Department of PsychologyNorthwestern UniversityEvanstonIllinoisUSA
| | - Katharine N. Thakkar
- Department of PsychologyMichigan State UniversityEast LansingMichiganUSA
- Psychiatry and Behavioral MedicineMichigan State University College of Human MedicineEast LansingMichiganUSA
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3
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Le Boterff Q, Rabah A, Carment L, Bendjemaa N, Térémetz M, Alouit A, Levy A, Tanguy G, Morin V, Amado I, Cuenca M, Turc G, Maier MA, Krebs MO, Lindberg PG. A tablet-based quantitative assessment of manual dexterity for detection of early psychosis. Front Psychiatry 2023; 14:1200864. [PMID: 37435404 PMCID: PMC10330763 DOI: 10.3389/fpsyt.2023.1200864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 06/06/2023] [Indexed: 07/13/2023] Open
Abstract
Background We performed a pilot study on whether tablet-based measures of manual dexterity can provide behavioral markers for detection of first-episode psychosis (FEP), and whether cortical excitability/inhibition was altered in FEP. Methods Behavioral and neurophysiological testing was undertaken in persons diagnosed with FEP (N = 20), schizophrenia (SCZ, N = 20), autism spectrum disorder (ASD, N = 20), and in healthy control subjects (N = 20). Five tablet tasks assessed different motor and cognitive functions: Finger Recognition for effector (finger) selection and mental rotation, Rhythm Tapping for temporal control, Sequence Tapping for control/memorization of motor sequences, Multi Finger Tapping for finger individuation, and Line Tracking for visuomotor control. Discrimination of FEP (from other groups) based on tablet-based measures was compared to discrimination through clinical neurological soft signs (NSS). Cortical excitability/inhibition, and cerebellar brain inhibition were assessed with transcranial magnetic stimulation. Results Compared to controls, FEP patients showed slower reaction times and higher errors in Finger Recognition, and more variability in Rhythm Tapping. Variability in Rhythm Tapping showed highest specificity for the identification of FEP patients compared to all other groups (FEP vs. ASD/SCZ/Controls; 75% sensitivity, 90% specificity, AUC = 0.83) compared to clinical NSS (95% sensitivity, 22% specificity, AUC = 0.49). Random Forest analysis confirmed FEP discrimination vs. other groups based on dexterity variables (100% sensitivity, 85% specificity, balanced accuracy = 92%). The FEP group had reduced short-latency intra-cortical inhibition (but similar excitability) compared to controls, SCZ, and ASD. Cerebellar inhibition showed a non-significant tendency to be weaker in FEP. Conclusion FEP patients show a distinctive pattern of dexterity impairments and weaker cortical inhibition. Easy-to-use tablet-based measures of manual dexterity capture neurological deficits in FEP and are promising markers for detection of FEP in clinical practice.
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Affiliation(s)
- Quentin Le Boterff
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
| | - Ayah Rabah
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
| | - Loïc Carment
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
| | - Narjes Bendjemaa
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
- GHU Paris Psychiatrie & Neurosciences, Paris, France
| | - Maxime Térémetz
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
| | - Anaëlle Alouit
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
| | - Agnes Levy
- GHU Paris Psychiatrie & Neurosciences, Paris, France
| | | | | | | | | | - Guillaume Turc
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
- GHU Paris Psychiatrie & Neurosciences, Paris, France
| | - Marc A. Maier
- CNRS, Integrative Neuroscience and Cognition Center, Université Paris Cité, Paris, France
| | - Marie-Odile Krebs
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
- GHU Paris Psychiatrie & Neurosciences, Paris, France
| | - Påvel G. Lindberg
- INSERM U1266 Institut de Psychiatrie et Neurosciences de Paris, Paris, France
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4
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Lazaridi M, Panagiotaropoulou G, Covanis P, Karantinos T, Aggelopoulos E, Klein C, Smyrnis N. Brain-Heart Link in Schizophrenia: Cognitive Inhibitory Control Deficit in Patients Is Specifically Related to Parasympathetic Dysregulation. Schizophr Bull 2022; 48:1155-1163. [PMID: 35357485 PMCID: PMC9434444 DOI: 10.1093/schbul/sbac033] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND This study examined the connection between two prominent deficits in schizophrenia: the deficit in parasympathetic regulation and the deficit in cognitive inhibitory control, within the framework of the Neurovisceral Integration Model (NIM). STUDY DESIGN Thirty healthy controls and 30 patients with schizophrenia performed the internationally standardized antisaccade protocol while their electrocardiographic data were recorded. The interaction between the group, the cognitive inhibitory control as measured with error rate (ER) in the antisaccade task and parasympathetic activity as measured with the High Frequency power component of Heart Rate Variability (HF-HRV) was tested. STUDY RESULTS Findings confirmed that decreased HF-HRV was specifically related to increased ER in patients with schizophrenia. In contrast, patient deficits in other oculomotor function measures such as reaction time and reaction time variability related to volitional movement control and cognitive stability respectively were not linked to the deficit in parasympathetic regulation. CONCLUSIONS Our study validates the theory behind NIM proposing that cognitive inhibition has common physiological substrate with parasympathetic regulation. Future research could test this brain-heart link in other mental disorders especially those with a prominent deficit in inhibitory cognitive function.
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Affiliation(s)
- Marina Lazaridi
- Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute “COSTAS STEFANIS”, Athens, Greece,1st Department of Psychiatry, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgia Panagiotaropoulou
- Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute “COSTAS STEFANIS”, Athens, Greece,Department of Psychiatry, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Panagiotis Covanis
- Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute “COSTAS STEFANIS”, Athens, Greece
| | - Thomas Karantinos
- Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute “COSTAS STEFANIS”, Athens, Greece
| | - Elias Aggelopoulos
- 1st Department of Psychiatry, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Christoph Klein
- 2nd Department of Psychiatry, University General Hospital “ATTIKON”, Medical School, National and Kapodistrian University of Athens, Athens, Greece,Department of Child and Adolescent Psychiatry, Medical Faculty, University of Freiburg, Freiburg, Germany,Department of Child and Adolescent Psychiatry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Nikolaos Smyrnis
- To whom correspondence should be addressed; 2nd Department of Psychiatry, National and Kapodistrian University of Athens, Medical School, University General Hospital “ATTIKON”, 1 Rimini St., Athens GR-12462, Greece; tel: +302105832426, fax: 2106528354, e-mail:
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Abstract
AbstractResearch on malingering detection has not yet taken full advantage of eye tracking technology. In particular, while several studies indicate that patients with schizophrenia behave notably differently from controls on specific oculomotor tasks, no study has yet investigated whether experimental participants instructed to feign could reproduce those behaviors, if coached to do so. Due to the automatic nature of eye movements, we anticipated that eye tracking analyses would help detect feigned schizophrenic problems. To test this hypothesis, we recorded the eye movements of 83 adult UK volunteers, and tested whether eye movements of healthy volunteers instructed to feign schizophrenia (n = 43) would differ from those of honest controls (n = 40), while engaging in smooth pursuit and pro- and anti-saccade tasks. Additionally, results from our investigation were also compared against previously published data observed in patients with schizophrenia performing similar oculomotor tasks. Data analysis showed that eye movements of experimental participants instructed to feign (a) only partially differed from those of controls and (b) did not closely resemble those from patients with schizophrenia reported in previously published papers. Taken together, these results suggest that examination of eye movements does have the potential to help detecting feigned schizophrenia.
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Athanasopoulos F, Saprikis OV, Margeli M, Klein C, Smyrnis N. Towards Clinically Relevant Oculomotor Biomarkers in Early Schizophrenia. Front Behav Neurosci 2021; 15:688683. [PMID: 34177483 PMCID: PMC8222521 DOI: 10.3389/fnbeh.2021.688683] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/11/2021] [Indexed: 12/30/2022] Open
Abstract
In recent years, psychiatric research has focused on the evaluation and implementation of biomarkers in the clinical praxis. Oculomotor function deviances are among the most consistent and replicable cognitive deficits in schizophrenia and have been suggested as viable candidates for biomarkers. In this narrative review, we focus on oculomotor function in first-episode psychosis, recent onset schizophrenia as well as individuals at high risk for developing psychosis. We critically discuss the evidence for the possible utilization of oculomotor function measures as diagnostic, susceptibility, predictive, monitoring, and prognostic biomarkers for these conditions. Based on the current state of research we conclude that there are not sufficient data to unequivocally support the use of oculomotor function measures as biomarkers in schizophrenia.
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Affiliation(s)
- Fotios Athanasopoulos
- 2nd Department of Psychiatry, School of Medicine, National and Kapodistrian University of Athens, University General Hospital "ATTIKON", Athens, Greece.,Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute "COSTAS STEFANIS", Athens, Greece
| | - Orionas-Vasilis Saprikis
- 2nd Department of Psychiatry, School of Medicine, National and Kapodistrian University of Athens, University General Hospital "ATTIKON", Athens, Greece.,Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute "COSTAS STEFANIS", Athens, Greece
| | - Myrto Margeli
- 2nd Department of Psychiatry, School of Medicine, National and Kapodistrian University of Athens, University General Hospital "ATTIKON", Athens, Greece.,Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute "COSTAS STEFANIS", Athens, Greece
| | - Christoph Klein
- 2nd Department of Psychiatry, School of Medicine, National and Kapodistrian University of Athens, University General Hospital "ATTIKON", Athens, Greece.,Department of Child and Adolescent Psychiatry, Medical Faculty, University of Freiburg, Freiburg, Germany.,Department of Child and Adolescent Psychiatry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Nikolaos Smyrnis
- 2nd Department of Psychiatry, School of Medicine, National and Kapodistrian University of Athens, University General Hospital "ATTIKON", Athens, Greece.,Laboratory of Cognitive Neuroscience and Sensorimotor Control, University Mental Health, Neurosciences and Precision Medicine Research Institute "COSTAS STEFANIS", Athens, Greece
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7
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Kleineidam L, Frommann I, Ruhrmann S, Klosterkötter J, Brockhaus-Dumke A, Wölwer W, Gaebel W, Maier W, Wagner M, Ettinger U. Antisaccade and prosaccade eye movements in individuals clinically at risk for psychosis: comparison with first-episode schizophrenia and prediction of conversion. Eur Arch Psychiatry Clin Neurosci 2019; 269:921-930. [PMID: 30635714 DOI: 10.1007/s00406-018-0973-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 12/19/2018] [Indexed: 02/03/2023]
Abstract
Saccadic eye movements are well-described markers of cerebral function and have been widely studied in schizophrenia spectrum populations. However, less is known about saccades in individuals clinically at risk for schizophrenia. Therefore, we studied individuals in an at-risk mental state (ARMS) (N = 160), patients in their first episode of schizophrenia (N = 32) and healthy controls (N = 75). N = 88 ARMS participants showed an early at-risk mental state (E-ARMS), defined by cognitive-perceptive basic symptoms (COPER) or a combination of risk and loss of function, whereas N = 72 were in a late at-risk mental state (L-ARMS), defined by attenuated psychotic symptoms or brief limited intermittent psychotic symptoms. We examined prosaccades, reflecting overt attentional shifts, and antisaccades, measuring inhibitory control, as well as their relationship as an indicator of the interplay of bottom-up and top-down influences. L-ARMS but not E-ARMS participants had increased antisaccade latencies compared to controls. First-episode patients had higher antisaccade error rates compared to E-ARMS participants and controls, and increased latencies compared to all other groups. Prosaccade latencies did not differ between groups. We observed the expected negative correlation between prosaccade latency and antisaccade error rate, indicating that individuals with shorter prosaccade latencies made more antisaccade errors. The magnitude of the association did not differ between groups. No saccadic measure predicted conversion to psychosis within 2 years. These findings confirm the existence of antisaccade impairments in patients with schizophrenia and provide evidence that volitional response generation in the antisaccade task may be affected even before onset of clinically overt psychosis.
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Affiliation(s)
- Luca Kleineidam
- Department of Psychiatry and Psychotherapy, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.,Department for Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany
| | - Ingo Frommann
- Department of Psychiatry and Psychotherapy, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.,Department for Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany
| | - Stephan Ruhrmann
- Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Joachim Klosterkötter
- Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Anke Brockhaus-Dumke
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, Rheinhessen-Fachklinik Alzey, Dautenheimer Landstraße 66, 55232, Alzey, Germany
| | - Wolfgang Wölwer
- Department of Psychiatry and Psychotherapy, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Wolfgang Gaebel
- Department of Psychiatry and Psychotherapy, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Wolfgang Maier
- Department of Psychiatry and Psychotherapy, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.,Department for Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany
| | - Michael Wagner
- Department of Psychiatry and Psychotherapy, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany. .,Department for Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.
| | - Ulrich Ettinger
- Department of Psychology, University of Bonn, Kaiser-Karl-Ring 9, 53111, Bonn, Germany
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8
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Whitford V, O'Driscoll GA, Titone D. Reading deficits in schizophrenia and their relationship to developmental dyslexia: A review. Schizophr Res 2018; 193:11-22. [PMID: 28688740 DOI: 10.1016/j.schres.2017.06.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/23/2017] [Accepted: 06/23/2017] [Indexed: 12/12/2022]
Abstract
Although schizophrenia and developmental dyslexia are considered distinct disorders in terms of clinical presentation and functional outcome, they both involve disruption in the processes that support skilled reading, including language, auditory perception, visual perception, oculomotor control, and executive function. Further, recent work has proposed a common neurodevelopmental basis for the two disorders, as suggested by genetic and pathophysiological overlap. Thus, these lines of research suggest that reading may be similarly impacted in schizophrenia and dyslexia. In this review, we survey research on reading abilities in individuals with schizophrenia, and review the potential mechanisms underlying reading deficits in schizophrenia that may be shared with those implicated in dyslexia. Elucidating the relationship between reading impairment in schizophrenia and dyslexia could allow for a better understanding of the pathophysiological underpinnings of schizophrenia, and could facilitate remediation of cognitive deficits that impact day-to-day functioning.
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Affiliation(s)
- Veronica Whitford
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 43 Vassar Street, Cambridge, MA 02139, United States; Graduate School of Education, Harvard University, 13 Appian Way, Cambridge, MA 02138, United States.
| | - Gillian A O'Driscoll
- Department of Psychology, McGill University, 1205 Doctor Penfield Avenue, Montreal, QC H3A 1B1, Canada; Department of Psychiatry, McGill University, 1033 Pine Avenue West, Montreal, QC H3A 1A1, Canada; Douglas Mental Health University Institute, McGill University, 6875 LaSalle Boulevard, Verdun, QC H4H 1R3, Canada; Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada.
| | - Debra Titone
- Department of Psychology, McGill University, 1205 Doctor Penfield Avenue, Montreal, QC H3A 1B1, Canada; Centre for Research on Brain, Language and Music, McGill University, 3640 de la Montagne Street, Montreal, QC H3G 2A8, Canada.
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9
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Clinical correlates of saccadic eye movement in antipsychotic-naïve schizophrenia. Psychiatry Res 2018; 259:154-159. [PMID: 29049907 DOI: 10.1016/j.psychres.2017.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/16/2017] [Accepted: 10/02/2017] [Indexed: 11/21/2022]
Abstract
Some aspects of saccadic performance have been found to be abnormal in chronic schizophrenia. The majority of this research has, however, been performed on patients treated with long-term antipsychotic medication. Very few studies have examined saccadic performance in antipsychotic-naïve/free patients. There are also very few studies describing the relationship between saccadic performance and clinical symptoms, particularly in antipsychotic free patients. In this study, we compared pro and antisaccade performance in a large sample of antipsychotic-naïve/free schizophrenia patients (N = 45) with healthy controls (N = 57). Clinical symptoms were assessed using Scale for Assessment of Positive Symptoms (SAPS) and Negative Symptoms (SANS). In the antisaccade task, patients made significantly more errors, and their correct antisaccades had smaller amplitudes in comparison to healthy controls. Higher error rates were associated with increased severity of hallucinations. In the prosaccade task, patients had less accurate final eye positions, and made saccades with slower latency and reduced amplitude compared to the healthy controls. These observations in schizophrenia patients without the potential confounds of antipsychotic treatment suggest intrinsic link between saccadic deficits and schizophrenia pathogenesis. The relationship between antisaccade errors and hallucination severity supports the potential link between hallucinations and deficits in inhibitory control.
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10
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Cutsuridis V. Behavioural and computational varieties of response inhibition in eye movements. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0196. [PMID: 28242730 DOI: 10.1098/rstb.2016.0196] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2016] [Indexed: 11/12/2022] Open
Abstract
Response inhibition is the ability to override a planned or an already initiated response. It is the hallmark of executive control as its deficits favour impulsive behaviours, which may be detrimental to an individual's life. This article reviews behavioural and computational guises of response inhibition. It focuses only on inhibition of oculomotor responses. It first reviews behavioural paradigms of response inhibition in eye movement research, namely the countermanding and antisaccade paradigms, both proven to be useful tools for the study of response inhibition in cognitive neuroscience and psychopathology. Then, it briefly reviews the neural mechanisms of response inhibition in these two behavioural paradigms. Computational models that embody a hypothesis and/or a theory of mechanisms underlying performance in both behavioural paradigms as well as provide a critical analysis of strengths and weaknesses of these models are discussed. All models assume the race of decision processes. The decision process in each paradigm that wins the race depends on different mechanisms. It has been shown that response latency is a stochastic process and has been proven to be an important measure of the cognitive control processes involved in response stopping in healthy and patient groups. Then, the inhibitory deficits in different brain diseases are reviewed, including schizophrenia and obsessive-compulsive disorder. Finally, new directions are suggested to improve the performance of models of response inhibition by drawing inspiration from successes of models in other domains.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'.
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11
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The Study of the Antisaccade Performance and Contingent Negative Variation Characteristics in First-Episode and Chronic Schizophrenia Patients. SPANISH JOURNAL OF PSYCHOLOGY 2017; 20:E55. [PMID: 29072157 DOI: 10.1017/sjp.2017.40] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The study tested whether the antisaccade (AS) performance and Contingent Negative Variation (CNV) measures differed between the first-episode and chronic patients to provide the evidence of PFC progressive functional deterioration. Subjects included 15 first-episode and 20 chronic schizophrenic patients (with the duration of illness more than 5 years), and 21 control subjects. The first-episode and chronic patients had significantly elevated error percent (p < .05, effect size 1.10 and p < .001, effect size 1.25), increased AS latencies (p < .01, effect size 1.18 and p < .001, effect size 1.69), and increased latencies variability (p < .01, effect size 1.52 and p < .001, effect size 1.37) compared to controls. Chronic patients had marginally significant increase of the response latency (p = .086, effect size .78) and latency variability (p < .099, effect size .63) compared to first-episode ones. Results of CNV analysis revealed that chronic patients only exhibited robustly declined frontal CNV amplitude at Fz (p < .05, effect size .70), F3 (p < .05, effect size .88), and F4 (p < .05, effect size .71) sites compared to controls. The obtained results might be related to specific changes in prefrontal cortex function over the course of schizophrenia.
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12
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Caffeine increases the velocity of rapid eye movements in unfatigued humans. Psychopharmacology (Berl) 2017; 234:2311-2323. [PMID: 28536868 DOI: 10.1007/s00213-017-4638-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 05/02/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND Caffeine is a widely used dietary stimulant that can reverse the effects of fatigue on cognitive, motor and oculomotor function. However, few studies have examined the effect of caffeine on the oculomotor system when homeostasis has not been disrupted by physical fatigue. This study examined the influence of a moderate dose of caffeine on oculomotor control and visual perception in participants who were not fatigued. METHODS Within a placebo-controlled crossover design, 13 healthy adults ingested caffeine (5 mg·kg-1 body mass) and were tested over 3 h. Eye movements, including saccades, smooth pursuit and optokinetic nystagmus, were measured using infrared oculography. RESULTS Caffeine was associated with higher peak saccade velocities (472 ± 60° s-1) compared to placebo (455 ± 62° s-1). Quick phases of optokinetic nystagmus were also significantly faster with caffeine, whereas pursuit eye movements were unchanged. Non-oculomotor perceptual tasks (global motion and global orientation processing) were unaffected by caffeine. CONCLUSIONS These results show that oculomotor control is modulated by a moderate dose of caffeine in unfatigued humans. These effects are detectable in the kinematics of rapid eye movements, whereas pursuit eye movements and visual perception are unaffected. Oculomotor functions may be sensitive to changes in central catecholamines mediated via caffeine's action as an adenosine antagonist, even when participants are not fatigued.
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Rodrigue AL, Austin BP, McDowell JE. Plasticity of prefrontal cortex connectivity in schizophrenia in response to antisaccade practice. Psychiatry Res Neuroimaging 2017; 265:77-86. [PMID: 27955939 DOI: 10.1016/j.pscychresns.2016.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 08/10/2016] [Accepted: 09/11/2016] [Indexed: 01/07/2023]
Abstract
People with schizophrenia exhibit difficulties in cognitive control that are often attributed to deficits in prefrontal cortex (PFC) circuitry. Practice paradigms have been used to improve these PFC-mediated deficits. The neural consequences of practice on task-based PFC activation have been addressed. Effects on task-based PFC connectivity, however, are largely unknown. We recruited people with schizophrenia and controls to practice antisaccades, a measure of PFC-mediated cognitive control that is disrupted in people with schizophrenia. Subjects performed antisaccades during functional magnetic resonance imaging (fMRI) before and after eight days of antisaccade practice. A group (schizophrenia, controls) × time (pre-, post-test) repeated measures ANOVA on the results of a psychophysiological interaction (PPI) analysis was used to evaluate changes in PFC connectivity; a similar model was used to evaluate changes in antisaccade behavior. After practice, antisaccade behavior improved and PFC connectivity with insular/temporal regions (involved in bottom-up orienting processes) increased in the schizophrenia group. The level of connectivity at post-test in the schizophrenia group was similar to that seen at pre-test in controls and positively correlated with antisaccade performance. Increases in connectivity between bottom-up and top-down regions may underlie behavioral improvements in people with schizophrenia after cognitive control practice.
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Fatigue-related impairments in oculomotor control are prevented by norepinephrine-dopamine reuptake inhibition. Sci Rep 2017; 7:42726. [PMID: 28198465 PMCID: PMC5309883 DOI: 10.1038/srep42726] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 01/12/2017] [Indexed: 11/09/2022] Open
Abstract
Fatigue-induced reductions in saccade velocity have been reported following acute, prolonged exercise. Interestingly, the detrimental impact of fatigue on oculomotor control can be prevented by a moderate dose of caffeine. This effect may be related to central catecholamine upregulation via caffeine's action as an adenosine antagonist. To test this hypothesis, we compared the protective effect of caffeine on oculomotor control post-exercise to that of a norepinephrine-dopamine reuptake inhibitor. Within a placebo-controlled crossover design, 12 cyclists consumed placebo, caffeine or a norepinephrine-dopamine reuptake inhibitor (bupropion) during 180 minutes of stationary cycling. Saccades, smooth pursuit and optokinetic nystagmus were measured using infrared oculography. Exercise fatigue was associated with an 8 ± 11% reduction in the peak velocity of prosaccades, and a 10 ± 11% decrement in antisaccade peak velocity. Optokinetic nystagmus quick phases decreased in velocity by 15 ± 17%. These differences were statistically significant (p < 0.05). Norepinephrine-dopamine reuptake inhibition and caffeine prevented fatigue-related decrements in eye movement velocity. Pursuit eye movements and visual attention were unaffected. These findings show that norepinephrine-dopamine reuptake inhibition protects oculomotor function during exercise fatigue. Caffeine's fatigue-reversing effects on eye movements appear to be mediated, at least in part, via modulation of central catecholamines.
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Naicker P, Anoopkumar-Dukie S, Grant GD, Kavanagh JJ. Medications influencing central cholinergic neurotransmission affect saccadic and smooth pursuit eye movements in healthy young adults. Psychopharmacology (Berl) 2017; 234:63-71. [PMID: 27671681 DOI: 10.1007/s00213-016-4436-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 09/12/2016] [Indexed: 11/30/2022]
Abstract
RATIONALE Acetylcholine is an important neuromodulator in the central nervous system, where it plays a significant role in central functions such as the regulation of movement. OBJECTIVE This study investigated the pharmacological effects of over-the-counter anticholinergic medications on saccadic and smooth pursuit eye movements, in order to establish the significance of central cholinergic pathways in the control of these centrally regulated oculomotor processes. METHODS Sixteen subjects (mean age 23 ± 3 years, 9 females) performed pro-saccadic, anti-saccadic and smooth pursuit eye movement tests, while an eye tracker collected eye movement data. Oculomotor assessments were performed pre-ingestion, 0.5 and 2 h post-ingestion of drugs with varying degrees of central anticholinergic properties. The drugs tested were promethazine, hyoscine hydrobromide, hyoscine butylbromide and placebo. RESULTS The drug intervention with stronger central anticholinergic properties, promethazine, decreased amplitude and increased velocity in the pro-saccadic task and increased duration in the anti-saccadic task. Promethazine, once again, was the only drug to decrease eye velocity in the smooth pursuit test. CONCLUSION The prominent effects of the stronger central anticholinergic promethazine, on saccadic and smooth pursuit eye movements, potentially conveys the significance of central cholinergic pathways in the control of these centrally regulated oculomotor processes.
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Affiliation(s)
- Preshanta Naicker
- Menzies Health Institute, Griffith University, Gold Coast, QLD, Australia.,School of Pharmacy, Griffith University, Gold Coast, QLD, Australia
| | - Shailendra Anoopkumar-Dukie
- Menzies Health Institute, Griffith University, Gold Coast, QLD, Australia.,School of Pharmacy, Griffith University, Gold Coast, QLD, Australia
| | - Gary D Grant
- Menzies Health Institute, Griffith University, Gold Coast, QLD, Australia.,School of Pharmacy, Griffith University, Gold Coast, QLD, Australia
| | - Justin J Kavanagh
- Menzies Health Institute, Griffith University, Gold Coast, QLD, Australia. .,Centre for Musculoskeletal Research, Griffith University, Gold Coast, QLD, 4222, Australia.
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Naicker P, Anoopkumar-Dukie S, Grant GD, Kavanagh JJ. Anticholinergic activity in the nervous system: Consequences for visuomotor function. Physiol Behav 2016; 170:6-11. [PMID: 27965143 DOI: 10.1016/j.physbeh.2016.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 12/08/2016] [Accepted: 12/08/2016] [Indexed: 12/16/2022]
Abstract
Acetylcholine is present in the peripheral and central nervous system, where it is involved in a number of fundamental physiological and biochemical processes. In particular, interaction with muscarinic receptors can cause adverse effects such as dry mouth, drowsiness, mydriasis and cognitive dysfunction. Despite the knowledge that exists regarding these common side-effects, little is known about how anticholinergic medications influence central motor processes and fine motor control in healthy individuals. This paper reviews critical visuomotor processes that operate in healthy individuals, and how controlling these motor processes are influenced by medications that interfere with central cholinergic neurotransmission. An overview of receptor function and neurotransmitter interaction following the ingestion or administration of anticholinergics is provided, before exploring how visuomotor performance is affected by anticholinergic medications. In particular, this review will focus on the effects that anticholinergic medications have on fixation stability, saccadic eye movements, smooth pursuit eye movements, and general pupil dynamics.
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Affiliation(s)
- Preshanta Naicker
- Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia; School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia
| | - Shailendra Anoopkumar-Dukie
- Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia; School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia
| | - Gary D Grant
- Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia; School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia
| | - Justin J Kavanagh
- Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia; School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia.
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Ye W, Liu S, Liu X, Yu Y. A neural model of the frontal eye fields with reward-based learning. Neural Netw 2016; 81:39-51. [PMID: 27284696 DOI: 10.1016/j.neunet.2016.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 05/03/2016] [Accepted: 05/06/2016] [Indexed: 11/24/2022]
Abstract
Decision-making is a flexible process dependent on the accumulation of various kinds of information; however, the corresponding neural mechanisms are far from clear. We extended a layered model of the frontal eye field to a learning-based model, using computational simulations to explain the cognitive process of choice tasks. The core of this extended model has three aspects: direction-preferred populations that cluster together the neurons with the same orientation preference, rule modules that control different rule-dependent activities, and reward-based synaptic plasticity that modulates connections to flexibly change the decision according to task demands. After repeated attempts in a number of trials, the network successfully simulated three decision choice tasks: an anti-saccade task, a no-go task, and an associative task. We found that synaptic plasticity could modulate the competition of choices by suppressing erroneous choices while enhancing the correct (rewarding) choice. In addition, the trained model captured some properties exhibited in animal and human experiments, such as the latency of the reaction time distribution of anti-saccades, the stop signal mechanism for canceling a reflexive saccade, and the variation of latency to half-max selectivity. Furthermore, the trained model was capable of reproducing the re-learning procedures when switching tasks and reversing the cue-saccade association.
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Affiliation(s)
- Weijie Ye
- School of Mathematics, South China University of Technology, Guangzhou, 510640, China
| | - Shenquan Liu
- School of Mathematics, South China University of Technology, Guangzhou, 510640, China.
| | - Xuanliang Liu
- School of Mathematics, South China University of Technology, Guangzhou, 510640, China
| | - Yuguo Yu
- Center for Computational Systems Biology, The State Key Laboratory of Medical Neurobiology and Institutes of Brain Science, Fudan University, School of Life Sciences, Shanghai, 200433, China
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Connell CJW, Thompson B, Kuhn G, Claffey MP, Duncan S, Gant N. Fatigue related impairments in oculomotor control are prevented by caffeine. Sci Rep 2016; 6:26614. [PMID: 27222342 PMCID: PMC4879569 DOI: 10.1038/srep26614] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 05/04/2016] [Indexed: 01/26/2023] Open
Abstract
Strenuous exercise can result in an inability of the central nervous system to drive skeletal muscle effectively, a phenomenon known as central fatigue. The impact of central fatigue on the oculomotor system is currently unexplored. Fatigue that originates in the central nervous system may be related to perturbations in the synthesis and metabolism of several neurotransmitters. In this study we examine central fatigue in the oculomotor system after prolonged exercise. The involvement of central neurotransmission was explored by administering caffeine during exercise. Within a double-blind, randomized, repeated measures, crossover design, 11 cyclists consumed a placebo or caffeine solution during 180 min of stationary cycling. Saccadic eye movements were measured using infra-red oculography. Exercise decreased saccade velocity by 8% (placebo trial). This effect was reversed by caffeine, whereby velocity was increased by 11% after exercise. A non-oculomotor perceptual task (global motion processing) was unaffected by exercise. The human oculomotor system is impaired by strenuous exercise of the locomotor system. Caffeine exerts a protective effect on oculomotor control, which could be related to up-regulated central neurotransmission. In addition, cortical processes supporting global motion perception appear to be robust to fatigue.
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Affiliation(s)
- Charlotte J W Connell
- Department of Exercise Sciences, Centre for Brain Research, University of Auckland, Auckland, NZ
| | - Benjamin Thompson
- School of Optometry and Vision Science, University of Waterloo, Canada
| | - Gustav Kuhn
- Department of Psychology, Goldsmiths, University of London, London, UK
| | | | - Shelley Duncan
- Department of Exercise Sciences, Centre for Brain Research, University of Auckland, Auckland, NZ
| | - Nicholas Gant
- Department of Exercise Sciences, Centre for Brain Research, University of Auckland, Auckland, NZ
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Thibaut F, Boutros NN, Jarema M, Oranje B, Hasan A, Daskalakis ZJ, Wichniak A, Schmitt A, Riederer P, Falkai P. Consensus paper of the WFSBP Task Force on Biological Markers: Criteria for biomarkers and endophenotypes of schizophrenia part I: Neurophysiology. World J Biol Psychiatry 2016. [PMID: 26213111 DOI: 10.3109/15622975.2015.1050061] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The neurophysiological components that have been proposed as biomarkers or as endophenotypes for schizophrenia can be measured through electroencephalography (EEG) and magnetoencephalography (MEG), transcranial magnetic stimulation (TMS), polysomnography (PSG), registration of event-related potentials (ERPs), assessment of smooth pursuit eye movements (SPEM) and antisaccade paradigms. Most of them demonstrate deficits in schizophrenia, show at least moderate stability over time and do not depend on clinical status, which means that they fulfil the criteria as valid endophenotypes for genetic studies. Deficits in cortical inhibition and plasticity measured using non-invasive brain stimulation techniques seem promising markers of outcome and prognosis. However the utility of these markers as biomarkers for predicting conversion to psychosis, response to treatments, or for tracking disease progression needs to be further studied.
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Affiliation(s)
- Florence Thibaut
- Department of Psychiatry, University Hospital Cochin (site Tarnier), University of Paris-Descartes, INSERM U 894 Centre Psychiatry and Neurosciences , Paris , France
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20
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Abstract
AbstractObjectives: It is increasingly important to develop predictors of treatment response and outcome in schizophrenia. Neuropsychological impairments, particularly those reflecting frontal lobe function, appear to predict poor outcome. Eye movement abnormalities probably also reflect frontal lobe deficits. We wished to see if these two aspects of schizophrenia were correlated and whether they could distinguish a treatment resistant from a treatment responsive group.Methods: Ten treatment resistant schizophrenic patients were compared with ten treatment responsive patients on three eye movement paradigms (reflexive saccades, antisaccades and smooth pursuit), clinical psychopathology (BPRS, SANS and CGI) and a neuropsychological test battery designed to detect frontal lobe dysfunction. Ten aged-matched controls also carried out the eye movement tasks.Results: Both treatment responsive (p = 0.038) and treatment resistant (p = 0.007) patients differed significantly from controls on the antisaccade task. The treatment resistant group had a higher error rate than the treatment responsive group, but the difference was not statistically significant. Similar poor neuropsychological test performance was found in both groups.Conclusions: To demonstrate the biological differences characteristic of treatment resistance, larger sample sizes and wider differences in outcome between the two groups are necessary.
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Cutsuridis V, Kumari V, Ettinger U. Antisaccade performance in schizophrenia: a neural model of decision making in the superior colliculus. Front Neurosci 2014; 8:13. [PMID: 24574953 PMCID: PMC3920187 DOI: 10.3389/fnins.2014.00013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 01/20/2014] [Indexed: 11/14/2022] Open
Abstract
Antisaccade performance deficits in schizophrenia are generally interpreted as an impaired top–down inhibitory signal failing to suppress the erroneous response. We recorded the antisaccade performance (error rates and latencies) of healthy and schizophrenia subjects performing the mirror antisaccade task. A neural rise-to-threshold model of antisaccade performance was developed to uncover the biophysical mechanisms giving rise to the observed deficits in schizophrenia. Schizophrenia patients displayed greater variability in the antisaccade and corrected antisaccade latency distributions, increased error rates and decreased corrected errors, relative to healthy participants. Our model showed that (1) increased variability is due to a more noisy accumulation of information by schizophrenia patients, but their confidence level required before making a decision is unaffected, and (2) competition between the correct and erroneous decision processes, and not a third top-down inhibitory signal suppressing the erroneous response, accounts for the antisaccade performance of healthy and schizophrenia subjects. Local competition further ensured that a correct antisaccade is never followed by an error prosaccade.
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Affiliation(s)
- Vassilis Cutsuridis
- Institute of Molecular Biology and Biotechnology, Foundation for the Research and Technology-Hellas (FORTH) Heraklion, Greece
| | - Veena Kumari
- Department of Psychology, Institute of Psychiatry, King's College London London, UK ; South London and Maudsley NHS Foundation Trust, NIHR Biomedical Research Centre for Mental Health London, UK
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Bender J, Reuter B, Möllers D, Kaufmann C, Gallinat J, Kathmann N. Neural correlates of impaired volitional action control in schizophrenia patients. Psychophysiology 2013; 50:872-84. [PMID: 23790023 DOI: 10.1111/psyp.12060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 03/20/2013] [Indexed: 11/26/2022]
Abstract
Slowed initiation of volitional but not visually guided saccades indicates impaired volitional action control in schizophrenia patients (SZ). The present study aimed at identifying neural correlates of this specific deficit. Fourteen SZ and 13 healthy control participants (HC) underwent functional magnetic resonance imaging while performing volitional and visually guided saccades. SZ showed increased latencies in volitional but not in visually guided saccades. Brain activation during volitional saccades compared to visually guided saccades was increased in SZ compared to HC in several areas: the supplementary eye fields, suggesting inefficient production of volitional saccades; the prefrontal cortex, pointing to altered top down control on complex eye movements; and the left middle temporal area, suggesting changes in early sensory and attention processing during the volitional control of saccades in SZ.
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Affiliation(s)
- Julia Bender
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany.
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Adams RA, Stephan KE, Brown HR, Frith CD, Friston KJ. The computational anatomy of psychosis. Front Psychiatry 2013; 4:47. [PMID: 23750138 PMCID: PMC3667557 DOI: 10.3389/fpsyt.2013.00047] [Citation(s) in RCA: 451] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 05/16/2013] [Indexed: 11/13/2022] Open
Abstract
This paper considers psychotic symptoms in terms of false inferences or beliefs. It is based on the notion that the brain is an inference machine that actively constructs hypotheses to explain or predict its sensations. This perspective provides a normative (Bayes-optimal) account of action and perception that emphasizes probabilistic representations; in particular, the confidence or precision of beliefs about the world. We will consider hallucinosis, abnormal eye movements, sensory attenuation deficits, catatonia, and delusions as various expressions of the same core pathology: namely, an aberrant encoding of precision. From a cognitive perspective, this represents a pernicious failure of metacognition (beliefs about beliefs) that can confound perceptual inference. In the embodied setting of active (Bayesian) inference, it can lead to behaviors that are paradoxically more accurate than Bayes-optimal behavior. Crucially, this normative account is accompanied by a neuronally plausible process theory based upon hierarchical predictive coding. In predictive coding, precision is thought to be encoded by the post-synaptic gain of neurons reporting prediction error. This suggests that both pervasive trait abnormalities and florid failures of inference in the psychotic state can be linked to factors controlling post-synaptic gain - such as NMDA receptor function and (dopaminergic) neuromodulation. We illustrate these points using biologically plausible simulations of perceptual synthesis, smooth pursuit eye movements and attribution of agency - that all use the same predictive coding scheme and pathology: namely, a reduction in the precision of prior beliefs, relative to sensory evidence.
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Affiliation(s)
- Rick A Adams
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London , London , UK
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Adams RA, Perrinet LU, Friston K. Smooth pursuit and visual occlusion: active inference and oculomotor control in schizophrenia. PLoS One 2012; 7:e47502. [PMID: 23110076 PMCID: PMC3482214 DOI: 10.1371/journal.pone.0047502] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 09/17/2012] [Indexed: 01/08/2023] Open
Abstract
This paper introduces a model of oculomotor control during the smooth pursuit of occluded visual targets. This model is based upon active inference, in which subjects try to minimise their (proprioceptive) prediction error based upon posterior beliefs about the hidden causes of their (exteroceptive) sensory input. Our model appeals to a single principle – the minimisation of variational free energy – to provide Bayes optimal solutions to the smooth pursuit problem. However, it tries to accommodate the cardinal features of smooth pursuit of partially occluded targets that have been observed empirically in normal subjects and schizophrenia. Specifically, we account for the ability of normal subjects to anticipate periodic target trajectories and emit pre-emptive smooth pursuit eye movements – prior to the emergence of a target from behind an occluder. Furthermore, we show that a single deficit in the postsynaptic gain of prediction error units (encoding the precision of posterior beliefs) can account for several features of smooth pursuit in schizophrenia: namely, a reduction in motor gain and anticipatory eye movements during visual occlusion, a paradoxical improvement in tracking unpredicted deviations from target trajectories and a failure to recognise and exploit regularities in the periodic motion of visual targets. This model will form the basis of subsequent (dynamic causal) models of empirical eye tracking measurements, which we hope to validate, using psychopharmacology and studies of schizophrenia.
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Affiliation(s)
- Rick A Adams
- The Wellcome Trust Centre for Neuroimaging, University College London, Queen Square, London, United Kingdom.
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Beedie SA, Benson PJ, Giegling I, Rujescu D, St Clair DM. Smooth pursuit and visual scanpaths: Independence of two candidate oculomotor risk markers for schizophrenia. World J Biol Psychiatry 2012; 13:200-10. [PMID: 21545243 DOI: 10.3109/15622975.2011.566628] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Smooth pursuit and visual scanpath deficits are candidate trait markers for schizophrenia. It is not clear whether eye tracking dysfunction (ETD) and atypical scanpath behaviour are the product of the same underlying neurobiological processes. We have examined co-occurrence of ETD and scanpath disturbance in individuals with schizophrenia and healthy volunteers. METHODS Eye movements of individuals with schizophrenia (N = 96) and non-clinical age-matched comparison participants (N = 100) were recorded using non-invasive infrared oculography during smooth pursuit in both predictable (horizontal sinusoid) and less predictable (Lissajous sinusoid) conditions and a free viewing scanpath task. RESULTS Individuals with schizophrenia demonstrated scanning deficits in both tasks. There was no association between performance measures of smooth pursuit and scene scanpaths in patient or control groups. Odds ratios comparing the likelihood of scanpath dysfunction when ETD was present, and the likelihood of finding scanpath dysfunction when ETD was absent were not significant in patients or controls in either pursuit variant, suggesting that ETD and scanpath dysfunction are independent anomalies in schizophrenia. CONCLUSION ETD and scanpath disturbance appear to reflect independent oculomotor or neurocognitive deficits in schizophrenia. Each task may confer unique information about the pathophysiology of psychosis.
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Affiliation(s)
- Sara A Beedie
- School of Psychology, College of Life Sciences & Medicine, William Guild Building, University of Aberdeen, King's College, Aberdeen, UK.
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Revisiting the suitability of antisaccade performance as an endophenotype in schizophrenia. Brain Cogn 2011; 77:223-30. [DOI: 10.1016/j.bandc.2011.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 07/26/2011] [Accepted: 08/04/2011] [Indexed: 02/06/2023]
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Reflexive and volitional saccades: biomarkers of Huntington disease severity and progression. J Neurol Sci 2011; 313:35-41. [PMID: 22018763 DOI: 10.1016/j.jns.2011.09.035] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 09/27/2011] [Indexed: 11/21/2022]
Abstract
BACKGROUND Huntington disease (HD) is a genetic, neurodegenerative disorder characterized by chorea, behavioral co-morbidities, cognitive deficits, and eye movement abnormalities. We sought to evaluate whether reflexive and voluntary orienting prove useful as biomarkers of disease severity in HD. METHODS Eleven HD subjects were evaluated with the motor subscale of the Unified Huntington Disease Rating Scale (UHDRS) and the Montreal Cognitive Assessment. Using an infrared eye tracker, we also measured latency and error rates of horizontal and vertical saccades using prosaccade and antisaccade eye movement tasks. We calculated simple and age-controlled correlations between eye movement and clinical parameters. RESULTS Prosaccade latency correlated with total chorea score. HD patients with greater clinical severity were significantly slower in the prosaccade task. Antisaccade error rate also correlated with UHDRS motor score and total chorea score. HD patients with greater clinical severity as measured by either measure made significantly more errors in the antisaccade task. All these correlations remained significant even when age was taken into account. CONCLUSIONS The results of the present age-controlled study show for the first time that both reflexive and voluntary eye motor control in HD patients decrease with increase in disease severity suggesting declines in both motor and cognitive function. Thus, relatively simple eye movement parameters (latency and error rate) obtained from simple tasks (prosaccade and antisaccade) may serve as quantitative biomarkers of sub-cortical and cortical disease severity in HD and could aid in predicting onset, distinguishing subtypes, or evaluating disease progression and novel therapies.
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Larrison AL, Babin SL, Xing Y, Patel SS, Wassef AA, Sereno AB. Effects of adjunct valproic acid on clinical symptoms and saccadic eye movements in schizophrenia. Hum Psychopharmacol 2011; 26:517-25. [PMID: 22031266 DOI: 10.1002/hup.1236] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Valproic acid (VPA) has been suggested as a potential adjunct therapy in schizophrenia for the treatment of clinical symptoms and cognitive deficits. Here, we investigate the effects of VPA on clinical symptoms and saccadic eye movements while controlling for multiple medication effects. METHODS Remitted and first-episode schizophrenia patients taking haloperidol were given adjunct VPA for approximately 2 weeks and tested using a measure of clinical symptoms (Positive and Negative Syndrome Scale) and saccadic eye movement tasks over three testing periods. The effects of VPA were compared with schizophrenia patients medicated with equivalent doses of haloperidol alone (HAL group) and normal controls. RESULTS Schizophrenia patients had higher error rates on the antisaccade task (AS task) compared with normal controls. Adjunct VPA did not affect AS task error rates but was associated with an increase in response times for both saccade and AS tasks, with a significantly greater and dose-dependent increase in response times for the AS task. There were no differences in clinical improvement between VPA and HAL schizophrenia patient groups when controlling for haloperidol medication state. CONCLUSIONS These results suggest that adjuvant VPA therapy results in both sensorimotor and cognitive slowing but does not either help or further impair inhibitory control in schizophrenia, as measured by the elevated AS task errors.
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Affiliation(s)
- Abigail L Larrison
- Department of Education, University of California San Diego, San Diego, California, USA
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Abstract
Research on emotional processing in schizophrenia suggests relatively intact subjective responses to affective stimuli "in the moment." However, neuroimaging evidence suggests diminished activation in brain regions associated with emotional processing in schizophrenia. We asked whether given a more vulnerable cognitive system in schizophrenia, individuals with this disorder would show increased or decreased modulation of working memory (WM) as a function of the emotional content of stimuli compared with healthy control subjects. In addition, we examined whether higher anhedonia levels were associated with a diminished impact of emotion on behavioral and brain activation responses. In the present study, 38 individuals with schizophrenia and 32 healthy individuals completed blocks of a 2-back WM task in a functional magnetic resonance imaging scanning session. Blocks contained faces displaying either only neutral stimuli or neutral and emotional stimuli (happy or fearful faces), randomly intermixed and occurring both as targets and non-targets. Both groups showed higher accuracy but slower reaction time for negative compared to neutral stimuli. Individuals with schizophrenia showed intact amygdala activity in response to emotionally evocative stimuli, but demonstrated altered dorsolateral prefrontal cortex (DLPFC) and hippocampal activity while performing an emotionally loaded WM-task. Higher levels of social anhedonia were associated with diminished amygdala responses to emotional stimuli and increased DLPFC activity in individuals with schizophrenia. Emotional arousal may challenge dorsal-frontal control systems, which may have both beneficial and detrimental influences. Our findings suggest that disturbances in emotional processing in schizophrenia relate to alterations in emotion-cognition interactions rather than to the perception and subjective experience of emotion per se.
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Affiliation(s)
- Karla Becerril
- Neuroscience Program, Washington University, St. Louis, MO, USA.
| | - Deanna Barch
- Departments of Psychology, Psychiatry, and Radiology, Washington University, St. Louis, MO
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Babin SL, Hood AJ, Wassef AA, Williams NG, Patel SS, Sereno AB. Effects of haloperidol on cognition in schizophrenia patients depend on baseline performance: a saccadic eye movement study. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:1753-64. [PMID: 21689713 PMCID: PMC3169101 DOI: 10.1016/j.pnpbp.2011.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/03/2011] [Accepted: 06/03/2011] [Indexed: 11/16/2022]
Abstract
Schizophrenic patients are heterogeneous with respect to voluntary eye movement performance, with some showing impairment (e.g., high antisaccade error rates) and others having intact performance. To investigate how this heterogeneity may correlate with different cognitive outcomes after treatment, we used a prosaccade and antisaccade task to investigate the effects of haloperidol in schizophrenic subjects at three time points: baseline (before medication), 3-5 days post-medication, and 12-14 days post-medication. We also investigated changes on the Stroop Task and the Positive and Negative Syndrome Scale (PANSS) in these same subjects. Results were compared to matched controls. When considered as a single patient group, haloperidol had no effects across sessions on reflexive and voluntary saccadic eye movements of schizophrenic patients. In contrast, the performance of the Control group improved slightly but significantly across sessions on the voluntary eye movement task. When each subject was considered separately, interestingly, for schizophrenic patients change in voluntary eye movement performance across sessions depended on the baseline performance in a non-monotonic manner. That is, there was maximal worsening of voluntary eye movement performance at an intermediate level of baseline performance and the worsening decreased on either side of this intermediate baseline level. When patients were divided into categorical subgroups (nonimpaired and impaired), consistent with the non-monotonic relationship, haloperidol worsened voluntary eye movement performance in the nonimpaired patients and improved performance in the impaired patients. These results were only partially reflected in the Stroop Test. Both patient subgroups showed clinically significant improvement over time as measured by the PANSS. These findings suggest that haloperidol has different effects on cognitive performance in impaired and nonimpaired schizophrenic patients that are not evident in clinical ratings based on the PANSS. Given that good cognitive function is important for long-term prognosis and that there is heterogeneity in schizophrenia, these findings are critical for optimal evaluation and treatment of schizophrenic patients.
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Use of eye movement monitoring to examine item and relational memory in schizophrenia. Biol Psychiatry 2010; 68:610-6. [PMID: 20673874 PMCID: PMC2943005 DOI: 10.1016/j.biopsych.2010.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 06/03/2010] [Accepted: 06/07/2010] [Indexed: 11/24/2022]
Abstract
BACKGROUND Patients with schizophrenia may be impaired at remembering interitem and item-context relationships (relational memory), even when memory for items is intact. Here, we applied the novel approach of using eye movements to assess integrity of item and relational memory in schizophrenia. This method does not rely on introspection and may be more readily translated to animal models than traditional behavioral methods. METHODS Sixteen healthy control subjects and 16 patients were administered a scene memory task while eye movements were monitored. During testing, participants indicated whether the scenes were unchanged, contained a new item (item manipulation), had a change in item location (relational manipulation), or were new. It was predicted that memory would be disproportionately impaired when relational changes were made. RESULTS Results confirmed that tasks were equally difficult and showed that patients were impaired identifying all scene types. These behavioral impairments were associated with more severe disorganization and negative symptoms. Eye movement results were more specific. Both groups looked disproportionately at critical regions of repeated versus novel scenes-an effect of scene repetition. However, in contrast with predictions, patients showed equivalent eye-movement-based memory impairment whether changes were relational or item-based. CONCLUSIONS This is the first experiment to demonstrate that eye movements can be used to investigate item and relational memory in schizophrenia. The eye movement procedure was well tolerated and was more specific than behavioral measures with respect to memory impairment. Results suggest that eye movements may be of use in clinical trials and translational studies employing animal models.
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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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Levy DL, Sereno AB, Gooding DC, O'Driscoll GA. Eye tracking dysfunction in schizophrenia: characterization and pathophysiology. Curr Top Behav Neurosci 2010; 4:311-47. [PMID: 21312405 PMCID: PMC3212396 DOI: 10.1007/7854_2010_60] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Eye tracking dysfunction (ETD) is one of the most widely replicated behavioral deficits in schizophrenia and is over-represented in clinically unaffected first-degree relatives of schizophrenia patients. Here, we provide an overview of research relevant to the characterization and pathophysiology of this impairment. Deficits are most robust in the maintenance phase of pursuit, particularly during the tracking of predictable target movement. Impairments are also found in pursuit initiation and correlate with performance on tests of motion processing, implicating early sensory processing of motion signals. Taken together, the evidence suggests that ETD involves higher-order structures, including the frontal eye fields, which adjust the gain of the pursuit response to visual and anticipated target movement, as well as early parts of the pursuit pathway, including motion areas (the middle temporal area and the adjacent medial superior temporal area). Broader application of localizing behavioral paradigms in patient and family studies would be advantageous for refining the eye tracking phenotype for genetic studies.
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Affiliation(s)
- Deborah L Levy
- Psychology Research Laboratory, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
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Morgan CJ, Huddy V, Lipton M, Curran HV, Joyce EM. Is persistent ketamine use a valid model of the cognitive and oculomotor deficits in schizophrenia? Biol Psychiatry 2009; 65:1099-102. [PMID: 19111280 PMCID: PMC2777248 DOI: 10.1016/j.biopsych.2008.10.045] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 10/22/2008] [Accepted: 10/28/2008] [Indexed: 11/15/2022]
Abstract
BACKGROUND Acute ketamine has been shown to model features of schizophrenia such as psychotic symptoms, cognitive deficits and smooth pursuit eye movement dysfunction. There have been suggestions that chronic ketamine may also produce an analogue of the disorder. In this study, we investigated the effect of persistent recreational ketamine use on tests of episodic and working memory and on oculomotor tasks of smooth pursuit and pro- and antisaccades. METHODS Twenty ketamine users were compared with 1) 20 first-episode schizophrenia patients, 2) 17 polydrug control subjects who did not use ketamine but were matched to the ketamine users for other drug use, and 3) 20 non-drug-using control subjects. All groups were matched for estimated premorbid IQ. RESULTS Ketamine users made more antisaccade errors than both control groups but did not differ from patients. Ketamine users performed better than schizophrenia patients on smooth pursuit, antisaccade metrics, and both memory tasks but did not differ from control groups. CONCLUSIONS Problems inhibiting reflexive eye movements may be a consequence of repeated ketamine self-administration. The absence of any other oculomotor or cognitive deficit present in schizophrenia suggests that chronic self-administration of ketamine may not be a good model of these aspects of the disorder.
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Affiliation(s)
- Celia J.A. Morgan
- Clinical Psychopharmacology Unit, University College London, United Kingdom,Address reprints requests to Celia Morgan, Ph.D., Clinical Psychopharmacology Unit, Sub-Department of Clinical Health Psychology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Vyv Huddy
- Division of Neuroscience and Psychological Medicine, Imperial College London, United Kingdom
| | - Michelle Lipton
- Division of Neuroscience and Psychological Medicine, Imperial College London, United Kingdom
| | - H. Valerie Curran
- Clinical Psychopharmacology Unit, University College London, United Kingdom
| | - Eileen M. Joyce
- Division of Neuroscience and Psychological Medicine, Imperial College London, United Kingdom,Institute of Neurology, University College London, United Kingdom
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Abstract
The saccadic eye movement system provides researchers with a powerful tool with which to explore the cognitive control of behaviour. It is a behavioural system whose limited output can be measured with exceptional precision, and whose input can be controlled and manipulated in subtle ways. A range of cognitive processes (notably those involved in working memory and attention) have been shown to influence saccade parameters. Researchers interested in the relationship between cognitive function and psychiatric disorders have made extensive use of saccadic eye movement tasks to draw inferences as to the cognitive deficits associated with particular psychopathologies. The purpose of this review is to provide researchers with an overview of the research literature documenting cognitive involvement in saccadic tasks in healthy controls. An appreciation of this literature provides a solid background against which to interpret the deficits on saccadic tasks demonstrated in patient populations.
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Affiliation(s)
- S B Hutton
- Department of Psychology, University of Sussex, Pevensey 1 1c03, Brighton BN1 9RH, UK.
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Cocchi L, Debbané M, Vianin P, Bircher R, Roulin S, Conus P, Sarrasin-Bruchez P, Bovet P, Volken H, Wood SJ, Schenk F. Encoding dysfunctions in a dynamic-static paradigm for visuospatial working memory in first-episode psychosis patients: a 2-year follow-up study. Early Interv Psychiatry 2009; 3:44-51. [PMID: 21352174 DOI: 10.1111/j.1751-7893.2008.00101.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM To investigate static and dynamic visuospatial working memory (VSWM) processes in first-episode psychosis (FEP) patients and explore the validity of such measures as specific trait markers of schizophrenia. METHODS Twenty FEP patients and 20 age-, sex-, laterality- and education-matched controls carried out a dynamic and static VSWM paradigm. At 2-year follow up 13 patients met Diagnostic and Statistical Manual (of Mental Health Disorders)--Fourth Edition (DSM-IV) criteria for schizophrenia, 1 for bipolar disorder, 1 for brief psychotic episode and 5 for schizotypal personality disorder. RESULTS Compared with controls, the 20 FEP patients showed severe impairment in the dynamic VSWM condition but much less impairment in the static condition. No specific bias in stimulus selection was detected in the two tasks. Two-year follow-up evaluations suggested poorer baseline scores on the dynamic task clearly differentiated the 13 FEP patients who developed schizophrenia from the seven who did not. CONCLUSIONS Results suggest deficits in VSWM in FEP patients. Specific exploratory analyses further suggest that deficit in monitoring-manipulation VSWM processes, especially involved in our dynamic VSWM task, can be a reliable marker of schizophrenia.
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Affiliation(s)
- Luca Cocchi
- Institute of Sport Science and Physical Education, Department of Physiology, Lausanne University, Lausanne, Switzerland.
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Reilly JL, Lencer R, Bishop JR, Keedy S, Sweeney JA. Pharmacological treatment effects on eye movement control. Brain Cogn 2008; 68:415-35. [PMID: 19028266 PMCID: PMC3159189 DOI: 10.1016/j.bandc.2008.08.026] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2008] [Indexed: 10/21/2022]
Abstract
The increasing use of eye movement paradigms to assess the functional integrity of brain systems involved in sensorimotor and cognitive processing in clinical disorders requires greater attention to effects of pharmacological treatments on these systems. This is needed to better differentiate disease and medication effects in clinical samples, to learn about neurochemical systems relevant for identified disturbances, and to facilitate identification of oculomotor biomarkers of pharmacological effects. In this review, studies of pharmacologic treatment effects on eye movements in healthy individuals are summarized and the sensitivity of eye movements to a variety of pharmacological manipulations is established. Primary findings from these studies of healthy individuals involving mainly acute effects indicate that: (i) the most consistent finding across several classes of drugs, including benzodiazepines, first- and second- generation antipsychotics, anticholinergic agents, and anticonvulsant/mood stabilizing medications is a decrease in saccade and smooth pursuit velocity (or increase in saccades during pursuit); (ii) these oculomotor effects largely reflect the general sedating effects of these medications on central nervous system functioning and are often dose-dependent; (iii) in many cases changes in oculomotor functioning are more sensitive indicators of pharmacological effects than other measures; and (iv) other agents, including the antidepressant class of serotonergic reuptake inhibitors, direct serotonergic agonists, and stimulants including amphetamine and nicotine, do not appear to adversely impact oculomotor functions in healthy individuals and may well enhance aspects of saccade and pursuit performance. Pharmacological treatment effects on eye movements across several clinical disorders including schizophrenia, affective disorders, attention deficit hyperactivity disorder, Parkinson's disease, and Huntington's disease are also reviewed. While greater recognition and investigation into pharmacological treatment effects in these disorders is needed, both beneficial and adverse drug effects are identified. This raises the important caveat for oculomotor studies of neuropsychiatric disorders that performance differences from healthy individuals cannot be attributed to illness effects alone. In final sections of this review, studies are presented that illustrate the utility of eye movements for use as potential biomarkers in pharmacodynamic and pharmacogenetic studies. While more systematic studies are needed, we conclude that eye movement measurements hold significant promise as tools to investigate treatment effects on cognitive and sensorimotor processes in clinical populations and that their use may be helpful in speeding the drug development pathway for drugs targeting specific neural systems and in individualizing pharmacological treatments.
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Affiliation(s)
- James L Reilly
- Center for Cognitive Medicine, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Lencer R, Sprenger A, Harris MSH, Reilly JL, Keshavan MS, Sweeney JA. Effects of second-generation antipsychotic medication on smooth pursuit performance in antipsychotic-naive schizophrenia. ACTA ACUST UNITED AC 2008; 65:1146-54. [PMID: 18838631 DOI: 10.1001/archpsyc.65.10.1146] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Analyses of smooth pursuit eye movement parameters in patients with schizophrenia provide information about the integrity of neural networks mediating motion perception, sensorimotor transformation, and cognitive processes such as prediction. Although pursuit eye tracking deficits have been widely reported in schizophrenia, the integrity of discrete components of pursuit responses and the effect of second-generation antipsychotic medication on them are not well established. OBJECTIVE To examine different components of smooth pursuit performance in antipsychotic-naive patients with schizophrenia before and after treatment with second-generation antipsychotic medication. DESIGN, SETTING, AND PARTICIPANTS Thirty-three antipsychotic-naive patients with schizophrenia performed 3 different smooth pursuit paradigms designed to evaluate specific components of the pursuit response. All of the patients were retested after 6 weeks of treatment with risperidone or olanzapine. Testing was also performed with 39 matched healthy individuals. Thirteen patients and 21 healthy participants were retested after 26 and 52 weeks. MAIN OUTCOME MEASURES Pursuit initiation, maintenance gain (ratio of eye velocity over target velocity), and frequency of catch-up saccades during pursuit maintenance. RESULTS Prior to treatment, pursuit gain when tracking less predictable ramp targets tended to be reduced, latency of pursuit initiation was speeded, and catch-up saccade frequency was increased during predictive pursuit. After antipsychotic treatment initiation, pursuit gain decreased with ramp targets, indicating treatment-emergent impairments in sensorimotor processing. No changes were observed for predictive pursuit. Exploratory analyses in the subgroup with follow-up to 1 year revealed that these effects continued through long-term follow-up with some partial normalization at 1 year. Deficits were unrelated to drug dosage and clinical ratings. CONCLUSIONS Impaired sensorimotor function was observed after initiation of second-generation antipsychotic medications, which may be explained by their serotonergic antagonism of brainstem sensorimotor systems. Predictive mechanisms supported by frontostriatal-cerebellar circuitry were not affected by treatment initiation and appear able to compensate for treatment-emergent sensorimotor impairments during predictive tracking.
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Affiliation(s)
- Rebekka Lencer
- Department of Psychiatry, University of Lübeck, Lübeck, Germany
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Gooding DC, Basso MA. The tell-tale tasks: a review of saccadic research in psychiatric patient populations. Brain Cogn 2008; 68:371-90. [PMID: 18950927 DOI: 10.1016/j.bandc.2008.08.024] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2008] [Indexed: 10/21/2022]
Abstract
This review focuses on saccade research with adult psychiatric patients. It begins with an introduction of the various types of saccades and the tasks used to evoke them. The functional significance of the different types of eye movements is briefly discussed. Research findings regarding the saccadic performance of different adult psychiatric patient populations are discussed in detail, with particular emphasis on findings regarding error rates, response latencies, and any specific task parameters that might affect those variables. Findings regarding the symptom, neurocognitive, and neural correlates of saccadic performance and the functional significance of patients' saccadic deficits are also discussed. We also discuss the saccadic deficits displayed by various patient groups in terms of circuitry (e.g. cortical/basal ganglia circuits) that may be implicated in the underlying pathophysiology of several of these disorders. Future directions for research in this growing area are offered.
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Affiliation(s)
- Diane C Gooding
- Department of Psychology, University of Wisconsin-Madison, College of Letters and Sciences, 1202 West Johnson Street, Madison, WI 53706, USA.
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Smooth pursuit in schizophrenia: a meta-analytic review of research since 1993. Brain Cogn 2008; 68:359-70. [PMID: 18845372 DOI: 10.1016/j.bandc.2008.08.023] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2008] [Indexed: 11/22/2022]
Abstract
Abnormal smooth pursuit eye-tracking is one of the most replicated deficits in the psychophysiological literature in schizophrenia [Levy, D. L., Holzman, P. S., Matthysse, S., & Mendell, N. R. (1993). Eye tracking dysfunction and schizophrenia: A critical perspective. Schizophrenia Bulletin, 19, 461-505]. We used meta-analytic procedures to quantify patient-control differences in eye-tracking and to evaluate potential moderators of effect size including patient and target characteristics and characteristics of the control population (matched or not). The magnitude of patient-control differences in pursuit depended on the measure. Global measures had large effect sizes. Among specific measures, maintenance gain and leading saccades yielded large effect sizes, with gain also yielding the narrowest confidence interval. Effect sizes associated with specific measures of smooth pursuit vs. specific measures of intrusive saccades did not clearly implicate one system over the other. Patient demographics and target characteristics generally had little influence on effect sizes. However, studies that failed to sex-match patients and controls tended to have smaller effect sizes for maintenance gain and catch-up saccade rate. Average effect sizes and confidence limits for global measures of pursuit and for maintenance gain place these measures alongside the very strongest neurocognitive measures in the literature [Heinrichs, R. W. (2004). Meta-analysis, and the science of schizophrenia: Variant evidence or evidence of variants? Neuroscience and Biobehavioral Reviews, 28, 379-394] for distinguishing between patients with schizophrenia and controls.
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Eye movement deficits in schizophrenia: investigation of a genetically homogenous Icelandic sample. Eur Arch Psychiatry Clin Neurosci 2008; 258:373-83. [PMID: 18437278 DOI: 10.1007/s00406-008-0806-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 02/12/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND Deficits in antisaccade (AS) and smooth pursuit eye movements (SPEM) are promising endophenotypes in genetic studies of schizophrenia. The Icelandic population lends itself ideally to genetic studies due to its ethnic homogeneity and well-documented genealogy. The primary aim of this study was to assess AS and SPEM performance in a large Icelandic sample. Additional aims were to investigate the relationship between AS and SPEM task performance and to assess internal consistency, within-session performance changes and effects of SPEM target velocity on performance. METHOD Patients with schizophrenia (N = 118) and healthy controls (N = 109) matched for age and gender underwent infrared oculographic assessment of AS and SPEM (at target velocities of 12 degrees , 24 degrees and 36 degrees /s). RESULTS On the AS task patients displayed significantly more reflexive errors, longer latency, increased intra-individual latency variability, and reduced amplitude gain compared to controls. On the SPEM task, patients had significantly lower velocity gain and more frequent saccades during pursuit at all velocities, but group differences in velocity gain increased with increasing target velocity. Internal consistency of performance was high for all variables in both groups (Cronbach's alpha >0.77 for AS and >0.85 for SPEM) except for AS spatial error in patients (alpha = 0.38). A moderate association was found between AS and SPEM performance. By and large, patients and controls showed similar patterns of systematic within-session performance changes. CONCLUSIONS Our findings confirm the existence of robust eye movement deficits in schizophrenia in a large sample. These measures may be studied as endophenotypes in future studies of potential schizophrenia risk genotypes in the genetically homogenous Icelandic population.
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Hill SK, Harris MSH, Herbener ES, Pavuluri M, Sweeney JA. Neurocognitive allied phenotypes for schizophrenia and bipolar disorder. Schizophr Bull 2008; 34:743-59. [PMID: 18448479 PMCID: PMC2632447 DOI: 10.1093/schbul/sbn027] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Psychiatric disorders are genetically complex and represent the end product of multiple biological and social factors. Links between genes and disorder-related abnormalities can be effectively captured via assessment of phenotypes that are both associated with genetic effects and potentially contributory to behavioral abnormalities. Identifying intermediate or allied phenotypes as a strategy for clarifying genetic contributions to disorders has been successful in other areas of medicine and is a promising strategy for identifying susceptibility genes in complex psychiatric disorders. There is growing evidence that schizophrenia and bipolar disorder, rather than being wholly distinct disorders, share genetic risk at several loci. Further, there is growing evidence of similarity in the pattern of cognitive and neurobiological deficits in these groups, which may be the result of the effects of these common genetic factors. This review was undertaken to identify patterns of performance on neurocognitive and affective tasks across probands with schizophrenia and bipolar disorder as well as unaffected family members, which warrant further investigation as potential intermediate trait markers. Available evidence indicates that measures of attention regulation, working memory, episodic memory, and emotion processing offer potential for identifying shared and illness-specific allied neurocognitive phenotypes for schizophrenia and bipolar disorder. However, very few studies have evaluated neurocognitive dimensions in bipolar probands or their unaffected relatives, and much work in this area is needed.
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Affiliation(s)
- S. Kristian Hill
- To whom correspondence should be addressed; tel: 312 996-2107, fax: 312 413-8837, e-mail:
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Reilly JL, Harris MS, Khine TT, Keshavan MS, Sweeney JA. Reduced attentional engagement contributes to deficits in prefrontal inhibitory control in schizophrenia. Biol Psychiatry 2008; 63:776-83. [PMID: 18191110 PMCID: PMC2366792 DOI: 10.1016/j.biopsych.2007.11.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 10/16/2007] [Accepted: 11/09/2007] [Indexed: 11/25/2022]
Abstract
BACKGROUND Problems with the voluntary control of behavior, such as those leading to increased antisaccade errors, are accepted as evidence of prefrontal dysfunction in schizophrenia. We previously reported that speeded prosaccade responses, i.e., shorter response latencies for automatic shifts of attention to visual targets, were associated with higher antisaccade error rates in schizophrenia. This suggests that dysregulation of automatic attentional processes may contribute to disturbances in prefrontally mediated control of voluntary behavior. METHODS Twenty-four antipsychotic-naïve schizophrenia patients and 30 healthy individuals completed three tasks: a no-gap prosaccade task in which subjects shifted gaze toward a peripheral target that appeared coincident with the disappearance of a central fixation target and separate prosaccade and antisaccade tasks in which a temporal gap or overlap of the central target offset and peripheral target onset occurred. Sixteen patients were retested after 6 weeks of antipsychotic treatment. RESULTS Patients' prosaccade latencies in the no-gap task were speeded compared with healthy individuals. While patients were not atypical in the degree to which response latencies were speeded or slowed by the gap and overlap manipulations, those patients with diminished attentional engagement on the prosaccade task (i.e., reduced overlap effect) had significantly elevated antisaccade error rates. This effect persisted in patients evaluated after antipsychotic treatment. CONCLUSIONS This study provides evidence that a reduced ability to engage attention may render patients more distracted by sensory inputs, thereby further compromising impaired executive control during antisaccade tasks. Thus, alterations in attentional and executive control functions can synergistically disrupt voluntary behavioral responses in schizophrenia.
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Affiliation(s)
- James L. Reilly
- Center for Cognitive Medicine, University of Illinois at Chicago,Corresponding Author Address: Center for Cognitive Medicine, 912 S. Wood St., MC 913, University of Illinois at Chicago, Chicago, IL 60612, Phone: 312-355-2810, Fax: 312-413-8837,
| | | | - Tin T. Khine
- Center for Cognitive Medicine, University of Illinois at Chicago
| | | | - John A. Sweeney
- Center for Cognitive Medicine, University of Illinois at Chicago,University of Pittsburgh
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Rycroft N, Hutton SB, Clowry O, Groomsbridge C, Sierakowski A, Rusted JM. Non-cholinergic modulation of antisaccade performance: a modafinil-nicotine comparison. Psychopharmacology (Berl) 2007; 195:245-53. [PMID: 17676402 DOI: 10.1007/s00213-007-0885-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 06/27/2007] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The antisaccade task provides a powerful tool with which to investigate the cognitive and neural systems underlying goal-directed behaviour, particularly in situations when the correct behavioural response requires the suppression of a prepotent response. Antisaccade errors (failures to suppress reflexive prosaccades towards sudden-onset targets) are increased in patients with damage to the dorsolateral prefrontal cortex, and in patients with schizophrenia. Nicotine has been found to improve antisaccade performance in patients with schizophrenia and healthy controls. This performance enhancing effect may be due to direct effects on the cholinergic system, but there has been no test of this hypothesis. MATERIALS AND METHODS In a double blind, double dummy, placebo-controlled design, we compared the effect of nicotine and modafinil, a putative indirect noradrenergic agonist, on antisaccade performance in healthy non-smokers. RESULTS AND DISCUSSION Both compounds reduced latency for correct antisaccades, although neither reduced antisaccade errors. These findings are discussed with reference to the pharmacological route of performance enhancement on the antisaccade task and current models of antisaccade performance.
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Affiliation(s)
- N Rycroft
- Department of Psychology, Sussex University, Pevensey 1, Brighton, East Sussex, BN1 9QH, UK
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Abstract
Human head movement control can be considered as part of the oculomotor system since the control of gaze involves coordination of the eyes and head. Humans show a remarkable degree of flexibility in eye-head coordination strategies, nonetheless an individual will often demonstrate stereotypical patterns of eye-head behaviour for a given visual task. This review examines eye-head coordination in laboratory-based visual tasks, such as saccadic gaze shifts and combined eye-head pursuit, and in common tasks in daily life, such as reading. The effect of the aging process on eye-head coordination is then reviewed from infancy through to senescence. Consideration is also given to how pathology can affect eye-head coordination from the lowest through to the highest levels of oculomotor control, comparing conditions as diverse as eye movement restrictions and schizophrenia. Given the adaptability of the eye-head system we postulate that this flexible system is under the control of the frontal cortical regions, which assist in planning, coordinating and executing behaviour. We provide evidence for this based on changes in eye-head coordination dependant on the context and expectation of presented visual stimuli, as well as from changes in eye-head coordination caused by frontal lobe dysfunction.
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Affiliation(s)
- Frank Antony Proudlock
- Ophthalmology Group, RKCSB, Leicester Royal Infirmary, University Hospitals of Leicester, University of Leicester, Leicester, UK.
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46
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Nieman D, Becker H, van de Fliert R, Plat N, Bour L, Koelman H, Klaassen M, Dingemans P, Niessen M, Linszen D. Antisaccade task performance in patients at ultra high risk for developing psychosis. Schizophr Res 2007; 95:54-60. [PMID: 17656071 DOI: 10.1016/j.schres.2007.06.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 06/20/2007] [Accepted: 06/25/2007] [Indexed: 11/29/2022]
Abstract
Patients with schizophrenia consistently perform worse than healthy controls on the antisaccade task in which the subject is required to inhibit a reflexive saccade to a suddenly appearing visual target and look in the opposite direction. To our knowledge there is no research yet showing how patients at ultra high risk (UHR) for developing psychosis perform on the antisaccade task. The aim of the present study was to investigate antisaccade task performance in UHR patients. Patients were eligible for the study when they met criteria for one or more of the following groups: Attenuated symptoms or brief limited intermitted psychotic symptoms or a first-degree family member with a psychotic disorder and reduced functioning or basic symptoms. In 35 UHR patients we assessed antisaccades, neuropsychological test performance and symptomatology. Antisaccade task results were compared with those obtained in 42 age- and intelligence-matched patients with recent-onset schizophrenia and 28 matched healthy controls. Antisaccade error rate was significantly higher in the UHR patients than in the controls. Schizophrenia patients performed worse than the UHR patients and the control subjects. We found a trend towards higher antisaccade error rate at baseline in the UHR patients who later made the transition to psychosis compared to the UHR patients who did not make the transition to psychosis. Poor spatial working memory function was related to increased antisaccade errors in the UHR group. Abnormal antisaccade task performance is also present in patients at UHR for developing psychosis. Subsequent research needs to clarify if increased antisaccade error rate is predictive of a psychotic episode. In UHR patients, poor antisaccade performance may reflect working memory dysfunction.
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Affiliation(s)
- Dorien Nieman
- Department of Psychiatry, Academic Medical Center, Meibergdreef 5, 1105 AZ Amsterdam, Netherlands.
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47
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Manoach DS, Ketwaroo GA, Polli FE, Thakkar KN, Barton JJS, Goff DC, Fischl B, Vangel M, Tuch DS. Reduced microstructural integrity of the white matter underlying anterior cingulate cortex is associated with increased saccadic latency in schizophrenia. Neuroimage 2007; 37:599-610. [PMID: 17590354 DOI: 10.1016/j.neuroimage.2007.04.062] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 03/28/2007] [Accepted: 04/28/2007] [Indexed: 12/01/2022] Open
Abstract
The anterior cingulate cortex (ACC) is a key component of a network that directs both spatial attention and saccadic eye movements, which are tightly linked. Diffusion tensor imaging (DTI) has demonstrated reduced microstructural integrity of the anterior cingulum bundle as indexed by fractional anisotropy (FA) in schizophrenia, but the functional significance of these abnormalities is unclear. Using DTI, we examined the white matter underlying anterior cingulate cortex in schizophrenia to determine whether reduced FA is associated with prolonged latencies of volitional saccades. Seventeen chronic, medicated schizophrenia outpatients and nineteen healthy controls had high-resolution DTI scans. FA maps were registered to structural scans and mapped across participants using a surface-based coordinate system. Cingulate white matter was divided into rostral and dorsal anterior regions and a posterior region. Patients showed reduced FA in cingulate white matter of the right hemisphere. Reduced FA in the white matter underlying anterior cingulate cortex, frontal eye field, and posterior parietal cortex of the right hemisphere was associated with longer saccadic latencies in schizophrenia, though given the relatively small sample size, these relations warrant replication. These findings demonstrate that in schizophrenia, increased latency of volitional saccades is associated with reduced microstructural integrity of the white matter underlying key cortical components of a right-hemisphere dominant network for visuospatial attention and ocular motor control. Moreover, they suggest that anterior cingulate white matter abnormalities contribute to slower performance of volitional saccades and to inter-individual variability of saccadic latency in chronic, medicated schizophrenia.
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Affiliation(s)
- Dara S Manoach
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02215, USA.
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48
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Reuter B, Jäger M, Bottlender R, Kathmann N. Impaired action control in schizophrenia: The role of volitional saccade initiation. Neuropsychologia 2007; 45:1840-8. [PMID: 17258779 DOI: 10.1016/j.neuropsychologia.2006.12.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 09/30/2006] [Accepted: 12/11/2006] [Indexed: 10/23/2022]
Abstract
Schizophrenia patients show prefrontal cortex dysfunctions of neurodevelopmental origin, but the cognitive implications of these dysfunctions are not yet understood. This study used experimental variations of oculomotor tasks to evaluate the relative roles of volitional action initiation and the inhibition of reflexive behavior. Thirty schizophrenia patients and 30 control participants performed standard prosaccades (SP), standard antisaccades (SA), delayed prosaccades (DP), and delayed antisaccades (DA). The delayed tasks allowed separating the inhibition of erroneous prosaccades and the initiation of volitional saccades, which coincide in the SA task. Arrow-cued (AC) saccades were used to evaluate initiation without any inhibitory component. Erroneous prosaccades were less frequent in the delayed tasks than in the SA task. Error rates were generally larger in schizophrenia patients than in control participants, but the deficit was smaller in the delayed tasks than in the SA task. Correct saccade latencies of schizophrenia patients were normal in the SP task, but not on conditions of volitional saccade initiation (all other tasks). Volitional saccade latencies were positively correlated with error rates in the schizophrenia group. These results confirm that schizophrenia patients have a specific deficit in initiating volitional action, which may also contribute to the increased error rates.
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49
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Turetsky BI, Calkins ME, Light GA, Olincy A, Radant AD, Swerdlow NR. Neurophysiological endophenotypes of schizophrenia: the viability of selected candidate measures. Schizophr Bull 2007; 33:69-94. [PMID: 17135482 PMCID: PMC2632291 DOI: 10.1093/schbul/sbl060] [Citation(s) in RCA: 415] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In an effort to reveal susceptibility genes, schizophrenia research has turned to the endophenotype strategy. Endophenotypes are characteristics that reflect the actions of genes predisposing an individual to a disorder, even in the absence of diagnosable pathology. Individual endophenotypes are presumably determined by fewer genes than the more complex phenotype of schizophrenia and would, therefore, reduce the complexity of genetic analyses. Unfortunately, despite there being rational criteria to define a viable endophenotype, the term is sometimes applied indiscriminately to characteristics that are deviant in affected individuals. Schizophrenia patients exhibit deficits in several neurophysiological measures of information processing that have been proposed as candidate endophenotypes. Successful processing of sensory inputs requires the ability to inhibit intrinsic responses to redundant stimuli and, reciprocally, to facilitate responses to less frequent salient stimuli. There is evidence to suggest that both these processes are "impaired" in schizophrenia. Measures of inhibitory failure include prepulse inhibition of the startle reflex, P50 auditory evoked potential suppression, and antisaccade eye movements. Measures of impaired deviance detection include mismatch negativity and the P300 event-related potential. The purpose of this review is to systematically evaluate the endophenotype candidacy of these key neurophysiological abilities. For each candidate, we describe typical experimental procedures, the current understanding of the underlying neurobiology, the nature of the abnormality in schizophrenia, the reliability, stability and heritability of the measure, and any reported gene associations. We conclude with a discussion of the few studies thus far that have employed a multivariate approach with these candidates.
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Affiliation(s)
- Bruce I Turetsky
- Department of Psychiatry, 10th floor, Gates Building, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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50
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Rycroft N, Hutton SB, Rusted JM. The antisaccade task as an index of sustained goal activation in working memory: modulation by nicotine. Psychopharmacology (Berl) 2006; 188:521-9. [PMID: 16896958 DOI: 10.1007/s00213-006-0455-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 05/22/2006] [Indexed: 11/28/2022]
Abstract
INTRODUCTION The antisaccade task provides a laboratory analogue of situations in which execution of the correct behavioural response requires the suppression of a more prepotent or habitual response. Errors (failures to inhibit a reflexive prosaccade towards a sudden onset target) are significantly increased in patients with damage to the dorsolateral prefrontal cortex and patients with schizophrenia. Recent models of antisaccade performance suggest that errors are more likely to occur when the intention to initiate an antisaccade is insufficiently activated within working memory. Nicotine has been shown to enhance specific working memory processes in healthy adults. MATERIALS AND METHODS We explored the effect of nicotine on antisaccade performance in a large sample (N = 44) of young adult smokers. Minimally abstinent participants attended two test sessions and were asked to smoke one of their own cigarettes between baseline and retest during one session only. RESULTS AND CONCLUSION Nicotine reduced antisaccade errors and correct antisaccade latencies if delivered before optimum performance levels are achieved, suggesting that nicotine supports the activation of intentions in working memory during task performance. The implications of this research for current theoretical accounts of antisaccade performance, and for interpreting the increased rate of antisaccade errors found in some psychiatric patient groups are discussed.
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Affiliation(s)
- Nicola Rycroft
- Department of Psychology, University of Sussex, Brighton, East Sussex, BN1 9QH, UK
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