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Masselink J, Lappe M. Visuomotor learning from postdictive motor error. eLife 2021; 10:64278. [PMID: 33687328 PMCID: PMC8057815 DOI: 10.7554/elife.64278] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 03/04/2021] [Indexed: 01/02/2023] Open
Abstract
Sensorimotor learning adapts motor output to maintain movement accuracy. For saccadic eye movements, learning also alters space perception, suggesting a dissociation between the performed saccade and its internal representation derived from corollary discharge (CD). This is critical since learning is commonly believed to be driven by CD-based visual prediction error. We estimate the internal saccade representation through pre- and trans-saccadic target localization, showing that it decouples from the actual saccade during learning. We present a model that explains motor and perceptual changes by collective plasticity of spatial target percept, motor command, and a forward dynamics model that transforms CD from motor into visuospatial coordinates. We show that learning does not follow visual prediction error but instead a postdictive update of space after saccade landing. We conclude that trans-saccadic space perception guides motor learning via CD-based postdiction of motor error under the assumption of a stable world.
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Affiliation(s)
- Jana Masselink
- Institute for Psychology and Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Muenster, Münster, Germany
| | - Markus Lappe
- Institute for Psychology and Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Muenster, Münster, Germany
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Thakkar KN, Rolfs M. Disrupted Corollary Discharge in Schizophrenia: Evidence From the Oculomotor System. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2019; 4:773-781. [PMID: 31105039 PMCID: PMC6733648 DOI: 10.1016/j.bpsc.2019.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 03/04/2019] [Accepted: 03/22/2019] [Indexed: 01/18/2023]
Abstract
Corollary discharge (CD) signals are motor-related signals that exert an influence on sensory processing. They allow mobile organisms to predict the sensory consequences of their imminent actions. Among the many functions of CD is to provide a means by which we can distinguish sensory experiences caused by our own actions from those with external causes. In this way, they contribute to a subjective sense of agency. A disruption in the sense of agency is central to many of the clinical symptoms of schizophrenia, and abnormalities in CD signaling have been theorized to underpin particularly those agency-related psychotic symptoms of the illness. Characterizing abnormal CD associated with eye movements in schizophrenia and their resulting influence on visual processing and subsequent action plans may have advantages over other sensory and motor systems. That is because the most robust psychophysiological and neurophysiological data regarding the dynamics and influence of CD as well as the neural circuitry implicated in CD generation and transmission comes from the study of eye movements in humans and nonhuman primates. We review studies of oculomotor CD signaling in the schizophrenia spectrum and possible neurobiological correlates of CD disturbances. We conclude by speculating on the ways in which oculomotor CD dysfunction, specifically, may invoke specific experiences, clinical symptoms, and cognitive impairments. These speculations lay the groundwork for empirical study, and we conclude by outlining potentially fruitful research directions.
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Affiliation(s)
- Katharine N Thakkar
- Department of Psychology, Michigan State University, East Lansing, Michigan; Division of Psychiatry and Behavioral Medicine, Michigan State University, East Lansing, Michigan.
| | - Martin Rolfs
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany
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Caldani S, Amado I, Bendjemaa N, Vialatte F, Mam-Lam-Fook C, Gaillard R, Krebs MO, Pia Bucci M. Oculomotricity and Neurological Soft Signs: Can we refine the endophenotype? A study in subjects belonging to the spectrum of schizophrenia. Psychiatry Res 2017; 256:490-497. [PMID: 28759882 DOI: 10.1016/j.psychres.2017.06.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 06/02/2017] [Accepted: 06/04/2017] [Indexed: 12/24/2022]
Abstract
Alterations in eye tracking and motor impairments as well as Neurological Soft Signs (NSS) are frequently reported in patients with schizophrenia as well as in their relatives, and are proposed as endophenotype of the disease. This study investigated smooth pursuit eye movement and fixation task with distractors with a gap condition, two markers of inhibitory control mechanism, in 49 patients with schizophrenia, 24 ultra-high risk subjects, 41 full biological clinical siblings of patients and 48 controls. NSS were assessed as a marker of abnormal neurodevelopment. The results revealed more intrusive saccades respectively in smooth pursuit eye movement and in fixation task with distractors with a gap condition in patients, respect to controls and full siblings. Ultra high-risk participants with high NSS committed intrusive saccades compared to controls. Patients with schizophrenia with high NSS also displayed more of these abnormalities, compared to patients with schizophrenia with low NSS and controls. These findings highlight a global inhibitory control defect, and suggested that ultra-high risk subjects and patients with schizophrenia could share oculomotor abnormalities, especially when they express a high neurodevelopmental deviance. These oculomotor alterations might suggest that cerebral structures such as prefrontal and cerebellum could be involved in the expression of this vulnerability.
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Affiliation(s)
- Simona Caldani
- Université Paris Descartes, Sorbonne Paris Cité, INSERM, Centre de Psychiatrie et Neurosciences, UMR S 894, Physiopathologie des Maladies Psychiatriques, CNRS, GDR3557-Institut de Psychiatrie, Paris, France; UMR 1141 Inserm - Université Paris Diderot, Hôpital Robert Debré, 75019 Paris, France
| | - Isabelle Amado
- Université Paris Descartes, Sorbonne Paris Cité, INSERM, Centre de Psychiatrie et Neurosciences, UMR S 894, Physiopathologie des Maladies Psychiatriques, CNRS, GDR3557-Institut de Psychiatrie, Paris, France; Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - Narjes Bendjemaa
- Université Paris Descartes, Sorbonne Paris Cité, INSERM, Centre de Psychiatrie et Neurosciences, UMR S 894, Physiopathologie des Maladies Psychiatriques, CNRS, GDR3557-Institut de Psychiatrie, Paris, France
| | - François Vialatte
- UMR 8249 CNRS Laboratoire Plasticité du Cerveau, Paris 75005, France
| | - Célia Mam-Lam-Fook
- Université Paris Descartes, Sorbonne Paris Cité, INSERM, Centre de Psychiatrie et Neurosciences, UMR S 894, Physiopathologie des Maladies Psychiatriques, CNRS, GDR3557-Institut de Psychiatrie, Paris, France; Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - Raphael Gaillard
- Université Paris Descartes, Sorbonne Paris Cité, INSERM, Centre de Psychiatrie et Neurosciences, UMR S 894, Physiopathologie des Maladies Psychiatriques, CNRS, GDR3557-Institut de Psychiatrie, Paris, France; Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - Marie-Odile Krebs
- Université Paris Descartes, Sorbonne Paris Cité, INSERM, Centre de Psychiatrie et Neurosciences, UMR S 894, Physiopathologie des Maladies Psychiatriques, CNRS, GDR3557-Institut de Psychiatrie, Paris, France; Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France.
| | - Maria Pia Bucci
- UMR 1141 Inserm - Université Paris Diderot, Hôpital Robert Debré, 75019 Paris, France
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Thakkar KN, Diwadkar VA, Rolfs M. Oculomotor Prediction: A Window into the Psychotic Mind. Trends Cogn Sci 2017; 21:344-356. [PMID: 28292639 PMCID: PMC5401650 DOI: 10.1016/j.tics.2017.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 01/29/2017] [Accepted: 02/01/2017] [Indexed: 12/27/2022]
Abstract
Psychosis - an impaired contact with reality - is a hallmark of schizophrenia. Many psychotic symptoms are associated with disruptions in agency - the sense that 'I' cause my actions. A failure to predict sensory consequences of one's own actions may underlie agency disturbances. Such predictions rely on corollary discharge (CD) signals, 'copies' of movement commands sent to sensory regions prior to action execution. Here, we make a case that the oculomotor system is a promising model for understanding CD in psychosis, building on advances in our understanding of the behavioral and neurophysiological correlates of CD associated with eye movements. In this opinion article, we provide an overview of recent evidence for disturbed oculomotor CD in schizophrenia, potentially linking bizarre and disturbing psychotic experiences with basic physiological processes.
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Affiliation(s)
| | - Vaibhav A Diwadkar
- Department of Psychiatry and Behavioral Neurosciences, Brain Imaging Research Division, Wayne State University, Detroit, MI, USA
| | - Martin Rolfs
- Bernstein Center for Computational Neuroscience and Department of Psychology, Humboldt Universität, 10099 Berlin, Germany
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Instability of visual error processing for sensorimotor adaptation in schizophrenia. Eur Arch Psychiatry Clin Neurosci 2017; 267:237-244. [PMID: 27443319 DOI: 10.1007/s00406-016-0716-3] [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: 05/22/2016] [Accepted: 07/13/2016] [Indexed: 10/21/2022]
Abstract
Saccadic adaptation can be used to study disturbances of sensory processing and motor learning. We investigated whether patients with schizophrenia can adjust saccadic amplitudes to account for an increase in visual error while the saccade is in flight, and whether they transfer this change to a visuo-manual localization task. Fourteen patients (mean 37.1 years) and 14 healthy controls (mean 35.1 years) performed 200 adaptation trials of 10° with target shifts of 4° in the outward direction. We determined the percent amplitude change during adaptation and adaptation speed. In addition, subjects localized a stimulus that was flashed 50 ms after saccade target onset to measure the transfer of change in visual space perception to visuo-manual coordination. Eye movements were recorded at 1000 Hz. Saccade amplitudes increased over adaptation trials by 11 % (p < 0.001) similarly in both groups. Amplitude variability during adaptation was higher in patients (1.06° ± 0.32°) than in controls (0.71° ± 0.14°; p = 0.001), while adaptation speed was slower in patients (0.02 ± 0.03) than in controls (0.11 ± 0.11; p = 0.01). Other pre- and post-adaptation saccade metrics did not differ between groups. The adaptation process shifted localization of the flashed target in the adaptation direction similarly in both groups. The use of error signals for the internal recalibration of sensorimotor systems and the transfer of this recalibration to visual space perception appear basically unimpaired in schizophrenia. Higher amplitude variability in patients suggests a certain instability of saccadic control in cerebellar systems. Patients seem to rely on visual error processing in frontal circuitry, resulting in slower adaptation speeds, despite unimpaired adaptation strength.
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Caldani S, Bucci MP, Lamy JC, Seassau M, Bendjemaa N, Gadel R, Gaillard R, Krebs MO, Amado I. Saccadic eye movements as markers of schizophrenia spectrum: Exploration in at-risk mental states. Schizophr Res 2017; 181:30-37. [PMID: 27639418 DOI: 10.1016/j.schres.2016.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 09/01/2016] [Accepted: 09/01/2016] [Indexed: 01/27/2023]
Abstract
Schizophrenia is a neurodevelopmental disease with cognitive and motor impairments. Motor dysfunctions, such as eye movements or Neurological Soft Signs (NSS), are proposed as endophenotypic markers. Antisaccade (AS) and memory-guided saccades (MGS), two markers of inhibitory control mechanism, are altered in both patients with schizophrenia and their relatives, although these tools may have different sensitivities. Recently, emphasis has been put on identifying markers predictive of psychosis transition in subjects with ultra-high-risk psychosis in order to develop targeted prevention. This study investigates AS and MGS in 46 patients with schizophrenia, 23 ultra-high-risk subjects, and 39 full siblings compared to 47 healthy volunteers. NSS were assessed as a marker of abnormal neurodevelopment. The results revealed more errors in MGS in patients, ultra-high-risk subjects and siblings, than in controls, and more specifically ultra-high-risk subjects with high NSS scores. By contrast, the error rate in AS was significantly higher only in patients with schizophrenia compared to controls. These findings suggest that MGS could be more accurate to detect deficient inhibitory processes as a marker of vulnerability before the onset of schizophrenia. The use of the different paradigms (AS, MGS) revealed distinct profiles depending on the stage of the disease, indicating that some alterations could be pure endophenotypic markers of vulnerability for schizophrenia, while others could be markers of the disease progression.
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Affiliation(s)
- Simona Caldani
- UMR 1141 Inserm-Université Paris Diderot, Hôpital Robert Debré, 75019 Paris, France; INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France
| | - Maria Pia Bucci
- UMR 1141 Inserm-Université Paris Diderot, Hôpital Robert Debré, 75019 Paris, France
| | - Jean-Charles Lamy
- INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France; University Paris Descartes, Faculty of Medicine Paris Descartes, Service Hospitalo-Universitaire, Sainte-Anne Hospital, Paris, France
| | | | - Narjes Bendjemaa
- INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France; University Paris Descartes, Faculty of Medicine Paris Descartes, Service Hospitalo-Universitaire, Sainte-Anne Hospital, Paris, France
| | - Rémi Gadel
- INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France; University Paris Descartes, Faculty of Medicine Paris Descartes, Service Hospitalo-Universitaire, Sainte-Anne Hospital, Paris, France
| | - Raphael Gaillard
- INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France; University Paris Descartes, Faculty of Medicine Paris Descartes, Service Hospitalo-Universitaire, Sainte-Anne Hospital, Paris, France
| | - Marie-Odile Krebs
- INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France; University Paris Descartes, Faculty of Medicine Paris Descartes, Service Hospitalo-Universitaire, Sainte-Anne Hospital, Paris, France.
| | - Isabelle Amado
- INSERM U894, Laboratory of Pathophysiology of Psychiatric Diseases, Center of Psychiatry and Neurosciences, Institut de Psychiatrie, GDR3557, France; University Paris Descartes, Faculty of Medicine Paris Descartes, Service Hospitalo-Universitaire, Sainte-Anne Hospital, Paris, France
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Teng YL, Chen CL, Lou SZ, Wang WT, Wu JY, Ma HI, Chen VCH. Postural Stability of Patients with Schizophrenia during Challenging Sensory Conditions: Implication of Sensory Integration for Postural Control. PLoS One 2016; 11:e0158219. [PMID: 27355830 PMCID: PMC4927090 DOI: 10.1371/journal.pone.0158219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 06/13/2016] [Indexed: 11/19/2022] Open
Abstract
Postural dysfunctions are prevalent in patients with schizophrenia and affect their daily life and ability to work. In addition, sensory functions and sensory integration that are crucial for postural control are also compromised. This study intended to examine how patients with schizophrenia coordinate multiple sensory systems to maintain postural stability in dynamic sensory conditions. Twenty-nine patients with schizophrenia and 32 control subjects were recruited. Postural stability of the participants was examined in six sensory conditions of different level of congruency of multiple sensory information, which was based on combinations of correct, removed, or conflicting sensory inputs from visual, somatosensory, and vestibular systems. The excursion of the center of pressure was measured by posturography. Equilibrium scores were derived to indicate the range of anterior-posterior (AP) postural sway, and sensory ratios were calculated to explore ability to use sensory information to maintain balance. The overall AP postural sway was significantly larger for patients with schizophrenia compared to the controls [patients (69.62±8.99); controls (76.53±7.47); t1,59 = -3.28, p<0.001]. The results of mixed-model ANOVAs showed a significant interaction between the group and sensory conditions [F5,295 = 5.55, p<0.001]. Further analysis indicated that AP postural sway was significantly larger for patients compared to the controls in conditions containing unreliable somatosensory information either with visual deprivation or with conflicting visual information. Sensory ratios were not significantly different between groups, although small and non-significant difference in inefficiency to utilize vestibular information was also noted. No significant correlations were found between postural stability and clinical characteristics. To sum up, patients with schizophrenia showed increased postural sway and a higher rate of falls during challenging sensory conditions, which was independent of clinical characteristics. Patients further demonstrated similar pattern and level of utilizing sensory information to maintain balance compared to the controls.
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Affiliation(s)
- Ya-Ling Teng
- Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Occupational Therapy, College of Medical Science and Technology, Chung Shan Medical University, Taichung, Taiwan
- Occupational Therapy Room, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chiung-Ling Chen
- Department of Occupational Therapy, College of Medical Science and Technology, Chung Shan Medical University, Taichung, Taiwan
- Occupational Therapy Room, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Shu-Zon Lou
- Department of Occupational Therapy, College of Medical Science and Technology, Chung Shan Medical University, Taichung, Taiwan
| | - Wei-Tsan Wang
- Department of Psychiatry, Cen-Der Hospital, Taichung, Taiwan
| | - Jui-Yen Wu
- Department of Psychiatry, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Hui-Ing Ma
- Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Occupational Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- * E-mail:
| | - Vincent Chin-Hung Chen
- Department of Psychiatry, Chiayi Chang Gung Memorial Hospital & Chang Gung University, Chiayi, Taiwan
- School of Medicine, Chang Gung University, Taoyuan, Taiwan
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Shalaginova IG, Vakoliuk IA, Ecina IG. Parameters of prosaccades and antisaccades as potential markers of anxiety disorders. Zh Nevrol Psikhiatr Im S S Korsakova 2016; 116:61-67. [DOI: 10.17116/jnevro201611612161-67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Landgraf S, Osterheider M. "To see or not to see: that is the question." The "Protection-Against-Schizophrenia" (PaSZ) model: evidence from congenital blindness and visuo-cognitive aberrations. Front Psychol 2013; 4:352. [PMID: 23847557 PMCID: PMC3696841 DOI: 10.3389/fpsyg.2013.00352] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/30/2013] [Indexed: 12/12/2022] Open
Abstract
The causes of schizophrenia are still unknown. For the last 100 years, though, both “absent” and “perfect” vision have been associated with a lower risk for schizophrenia. Hence, vision itself and aberrations in visual functioning may be fundamental to the development and etiological explanations of the disorder. In this paper, we present the “Protection-Against-Schizophrenia” (PaSZ) model, which grades the risk for developing schizophrenia as a function of an individual's visual capacity. We review two vision perspectives: (1) “Absent” vision or how congenital blindness contributes to PaSZ and (2) “perfect” vision or how aberrations in visual functioning are associated with psychosis. First, we illustrate that, although congenitally blind and sighted individuals acquire similar world representations, blind individuals compensate for behavioral shortcomings through neurofunctional and multisensory reorganization. These reorganizations may indicate etiological explanations for their PaSZ. Second, we demonstrate that visuo-cognitive impairments are fundamental for the development of schizophrenia. Deteriorated visual information acquisition and processing contribute to higher-order cognitive dysfunctions and subsequently to schizophrenic symptoms. Finally, we provide different specific therapeutic recommendations for individuals who suffer from visual impairments (who never developed “normal” vision) and individuals who suffer from visual deterioration (who previously had “normal” visual skills). Rather than categorizing individuals as “normal” and “mentally disordered,” the PaSZ model uses a continuous scale to represent psychiatrically relevant human behavior. This not only provides a scientific basis for more fine-grained diagnostic assessments, earlier detection, and more appropriate therapeutic assignments, but it also outlines a trajectory for unraveling the causes of abnormal psychotic human self- and world-perception.
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Affiliation(s)
- Steffen Landgraf
- Department for Forensic Psychiatry and Psychotherapy, District Hospital, University Regensburg Regensburg, Germany ; Berlin School of Mind and Brain, Humboldt Universität zu Berlin Berlin, Germany
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Bittencourt J, Velasques B, Teixeira S, Basile LF, Salles JI, Nardi AE, Budde H, Cagy M, Piedade R, Ribeiro P. Saccadic eye movement applications for psychiatric disorders. Neuropsychiatr Dis Treat 2013; 9:1393-409. [PMID: 24072973 PMCID: PMC3783508 DOI: 10.2147/ndt.s45931] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE The study presented here analyzed the patterns of relationship between oculomotor performance and psychopathology, focusing on depression, bipolar disorder, schizophrenia, attention-deficit hyperactivity disorder, and anxiety disorder. METHODS Scientific articles published from 1967 to 2013 in the PubMed/Medline, ISI Web of Knowledge, Cochrane, and SciELO databases were reviewed. RESULTS Saccadic eye movement appears to be heavily involved in psychiatric diseases covered in this review via a direct mechanism. The changes seen in the execution of eye movement tasks in patients with psychopathologies of various studies confirm that eye movement is associated with the cognitive and motor system. CONCLUSION Saccadic eye movement changes appear to be heavily involved in the psychiatric disorders covered in this review and may be considered a possible marker of some disorders. The few existing studies that approach the topic demonstrate a need to improve the experimental paradigms, as well as the methods of analysis. Most of them report behavioral variables (latency/reaction time), though electrophysiological measures are absent.
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Affiliation(s)
- Juliana Bittencourt
- Brain Mapping and Sensory Motor Integration Laboratory, Institute of Psychiatry, Federal University of Rio de Janeiro, Brazil ; Institute of Applied Neuroscience, Rio de Janeiro, Brazil ; Neurophysiology and Neuropsychology of Attention, Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil ; Laboratory of Physical Therapy, Veiga de Almeida University, Rio de Janeiro, Brazil
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Raffa M, Fendri C, Ben Othmen L, Slama H, Amri M, Kerkeni A, Mechri A. The reduction of superoxide dismutase activity is associated with the severity of neurological soft signs in patients with schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2012; 39:52-6. [PMID: 22658981 DOI: 10.1016/j.pnpbp.2012.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/08/2012] [Accepted: 05/08/2012] [Indexed: 01/22/2023]
Abstract
This study aimed to explore the relationship between antioxidant enzyme activities and neurological soft signs (NSS) in a sample of patients with schizophrenia. Sixty clinically stable patients with schizophrenia treated mostly by first-generation antipsychotics and 30 matched healthy controls were recruited. NSS were assessed in two groups by a standardized neurological examination (Krebs et al., 2000). The red blood cell (RBC) antioxidant activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were measured by spectrophotometry. RBC activities of all enzymes studied: SOD, GSH-Px and CAT, were significantly lower in the patients compared to control group. All NSS scores were significantly higher in the patients compared to healthy controls' scores. In the patients, a negative correlation was found between RBC SOD activity and NSS total score and motor coordination and motor integration sub-scores. The association between low SOD activity as a marker of oxidative stress and NSS in schizophrenic patients suggests a common pathological process of these abnormalities.
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Affiliation(s)
- Monia Raffa
- Research Laboratory "Trace Elements, Free Radicals and Antioxidants", Biophysics Department, Faculty of Medicine, 5000 Monastir, Tunisia
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