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Bansal S, Gaspar JM, Robinson BM, Leonard CJ, Hahn B, Luck SJ, Gold JM. Antisaccade Deficits in Schizophrenia Can Be Driven by Attentional Relevance of the Stimuli. Schizophr Bull 2020; 47:363-372. [PMID: 32766726 PMCID: PMC7965078 DOI: 10.1093/schbul/sbaa106] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The antisaccade task is considered a test of cognitive control because it creates a conflict between the strong bottom-up signal produced by the cue and the top-down goal of shifting gaze to the opposite side of the display. Antisaccade deficits in schizophrenia are thought to reflect impaired top-down inhibition of the prepotent bottom-up response to the cue. However, the cue is also a highly task-relevant stimulus that must be covertly attended to determine where to shift gaze. We tested the hypothesis that difficulty in overcoming the attentional relevance of the cue, rather than its bottom-up salience, is key in producing impaired performance in people with schizophrenia (PSZ). We implemented 3 versions of the antisaccade task in which we varied the bottom-up salience of the cue while holding its attentional relevance constant. We found that difficulty in performing a given antisaccade task-relative to a prosaccade version using the same stimuli-was largely independent of the cue's bottom-up salience. The magnitude of impairment in PSZ relative to control subjects was also independent of bottom-up salience. The greatest impairment was observed in a version where the cue lacked bottom-up salience advantage over other locations. These results indicate that the antisaccade deficit in PSZ does not reflect an impairment in overcoming bottom-up salience of the cue, but PSZ are instead impaired at overcoming its attentional relevance. This deficit may still indicate an underlying inhibitory control impairment but could also reflect a hyperfocusing of attentional resources on the cue.
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Affiliation(s)
- Sonia Bansal
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD,To whom correspondence should be addressed; Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228, USA; tel: (410)-402-6881, fax: (410)-401-7198, e-mail:
| | - John M Gaspar
- Department of Psychology, Center for Mind and Brain, University of California, Davis, CA
| | - Benjamin M Robinson
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD
| | - Carly J Leonard
- Department of Psychology, University of Colorado, Denver, CO
| | - Britta Hahn
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD
| | - Steven J Luck
- Department of Psychology, Center for Mind and Brain, University of California, Davis, CA
| | - James M Gold
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Catonsville, MD
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Morita K, Miura K, Fujimoto M, Yamamori H, Yasuda Y, Kudo N, Azechi H, Okada N, Koshiyama D, Ikeda M, Kasai K, Hashimoto R. Eye movement abnormalities and their association with cognitive impairments in schizophrenia. Schizophr Res 2019; 209:255-262. [PMID: 30661730 DOI: 10.1016/j.schres.2018.12.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 12/28/2018] [Accepted: 12/28/2018] [Indexed: 12/26/2022]
Abstract
BACKGROUND Eye movement abnormalities have been identified in schizophrenia; however, their relevance to cognition is still unknown. In this study, we explored the general relationship between eye movements and cognitive function. METHODS The three eye movement measures (scanpath length, horizontal position gain, and duration of fixations) that were previously reported to be useful in distinguishing subjects with schizophrenia from healthy subjects, as well as Wechsler Adult Intelligence Scale-III (WAIS-III) scores, were collected and tested for association in 113 subjects with schizophrenia and 404 healthy subjects. RESULTS Scanpath length was positively correlated with matrix reasoning and digit symbol coding in subjects with schizophrenia and correlated with vocabulary and symbol search in healthy subjects. Upon testing for interaction effects of diagnosis and scanpath length on correlated WAIS-III scores, a significant interaction effect was only observed for matrix reasoning. The positive correlation between scanpath length and matrix reasoning, which was specific to subjects with schizophrenia, remained significant after controlling for demographic confounders such as medication and negative symptoms. No correlation was observed between the two other eye movement measures and any of the WAIS-III scores. CONCLUSIONS Herein, we reveal novel findings on the association between eye-movement-based measures of visual exploration and cognitive scores requiring visual search in subjects with schizophrenia and in healthy subjects. The association between scanpath length and matrix reasoning, a measure of perceptual organization in subjects with schizophrenia, implies the existence of common cognitive processes, and subjects with longer scanpath length may be advantageous in performance of perceptual organization tasks.
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Affiliation(s)
- Kentaro Morita
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 1138655, Japan
| | - Kenichiro Miura
- Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Kyoto, Kyoto 6068501, Japan.
| | - Michiko Fujimoto
- Department of Psychiatry, Osaka University Graduate School of Medicine, D3, 2-2, Yamadaoka, Suita, Osaka 5650871, Japan; Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 1878553, Japan
| | - Hidenaga Yamamori
- Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 1878553, Japan; Japan Community Health care Organization Osaka Hospital, 4-2-78, Fukushima, Fukushima-ku, Osaka-city, Osaka 5530033, Japan
| | - Yuka Yasuda
- Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 1878553, Japan; Life Grow Brilliant Mental Clinic, Takahashi Bldg. 7F, 2-1-21, Shibata, Kita-ku, Osaka-city, Osaka 5300012, Japan
| | - Noriko Kudo
- Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 1878553, Japan
| | - Hirotsugu Azechi
- Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 1878553, Japan
| | - Naohiro Okada
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 1138655, Japan; The International Research Center for Neurointelligence (WPI-IRCN) at The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, 7-3-1, Hongo, Tokyo 1138655, Japan
| | - Daisuke Koshiyama
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 1138655, Japan
| | - Manabu Ikeda
- Department of Psychiatry, Osaka University Graduate School of Medicine, D3, 2-2, Yamadaoka, Suita, Osaka 5650871, Japan
| | - Kiyoto Kasai
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 1138655, Japan; The International Research Center for Neurointelligence (WPI-IRCN) at The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, 7-3-1, Hongo, Tokyo 1138655, Japan
| | - Ryota Hashimoto
- Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 1878553, Japan; Osaka University, D3, 2-2, Yamadaoka, Suita, Osaka 5650871, Japan.
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Stotesbury H, Gaigg SB, Kirhan S, Haenschel C. The influence of schizotypal traits on attention under high perceptual load. SCHIZOPHRENIA RESEARCH-COGNITION 2017; 11:6-10. [PMID: 29159135 PMCID: PMC5684432 DOI: 10.1016/j.scog.2017.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/26/2017] [Accepted: 10/27/2017] [Indexed: 11/17/2022]
Abstract
Schizophrenia Spectrum Disorders (SSD) are known to be characterised by abnormalities in attentional processes, but there are inconsistencies in the literature that remain unresolved. This article considers whether perceptual resource limitations play a role in moderating attentional abnormalities in SSD. According to perceptual load theory, perceptual resource limitations can lead to attenuated or superior performance on dual-task paradigms depending on whether participants are required to process, or attempt to ignore, secondary stimuli. If SSD is associated with perceptual resource limitations, and if it represents the extreme end of an otherwise normally distributed neuropsychological phenotype, schizotypal traits in the general population should lead to disproportionate performance costs on dual-task paradigms as a function of the perceptual task demands. To test this prediction, schizotypal traits were quantified via the Schizotypal Personality Questionnaire (SPQ) in 74 healthy volunteers, who also completed a dual-task signal detection paradigm that required participants to detect central and peripheral stimuli across conditions that varied in the overall number of stimuli presented. The results confirmed decreasing performance as the perceptual load of the task increased. More importantly, significant correlations between SPQ scores and task performance confirmed that increased schizotypal traits, particularly in the cognitive-perceptual domain, are associated with greater performance decrements under increasing perceptual load. These results confirm that attentional difficulties associated with SSD extend sub-clinically into the general population and suggest that cognitive-perceptual schizotypal traits may represent a risk factor for difficulties in the regulation of attention under increasing perceptual load.
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Affiliation(s)
- Hanne Stotesbury
- Cognitive Neuroscience Research Unit, Department of Psychology, City, University of London, Northampton Square, London EC1V 0HB, United Kingdom.,Imaging & Biophysics Unit, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, 30 Guildford St, London WC1N 1EH, United Kingdom
| | - Sebastian B Gaigg
- Cognitive Neuroscience Research Unit, Department of Psychology, City, University of London, Northampton Square, London EC1V 0HB, United Kingdom.,Autism Research Group, Department of Psychology, City, University of London, Northampton Square, London EC1V 0HB, United Kingdom
| | - Saim Kirhan
- Cognitive Neuroscience Research Unit, Department of Psychology, City, University of London, Northampton Square, London EC1V 0HB, United Kingdom.,Oxford Health NHS Foundation Trust, Littlemore Mental Health Centre, Oxford Clinic, Sandford Rd, Oxford OX4 4XN, United Kingdom
| | - Corinna Haenschel
- Cognitive Neuroscience Research Unit, Department of Psychology, City, University of London, Northampton Square, London EC1V 0HB, United Kingdom
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She S, Zhang B, Li X, Zhang X, Li R, Li J, Bi T, Zheng Y. Face-related visual search deficits in first-episode schizophrenia. Psychiatry Res 2017. [PMID: 28633055 DOI: 10.1016/j.psychres.2017.06.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Schizophrenia is considered a complex illness with multiple cognitive dysfunctions, including a deficit in visual processing. However, whether the deficiency of visual processing in schizophrenia is general across stimuli or stimulus-specific remains the subject of debate. In the current study, eighteen first-episode schizophrenic patients and eighteen healthy controls participated in three visual search tasks in which they were asked to search a specific target of a triangle, face identity or facial affect. The results showed that, compared to healthy controls, the accuracies for face identity and facial affect searches were significantly lower in schizophrenic patients, while the performance of the triangle search was the same. Furthermore, the accuracy of the facial affect search was negatively correlated to negative symptoms in schizophrenia. These results revealed a face-related deficit in schizophrenia and suggest that visual processing deficits in schizophrenia were stimuli-specific.
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Affiliation(s)
- Shenglin She
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China
| | - Bei Zhang
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China
| | - Xuanzi Li
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China
| | - Xiaofei Zhang
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China
| | - Ruikeng Li
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China
| | - Juanhua Li
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China
| | - Taiyong Bi
- Key Laboratory of Cognition and Personality (SWU), Ministry of Education, Chongqing 400715, China; Faculty of Psychology, Southwest University, Chongqing 400715, China; School of Management, Zunyi Medical University, Guizhou 563000, China.
| | - Yingjun Zheng
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), National Clinical Research Center on Mental Disorders (Changsha), Guangzhou 510370, China.
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Damaso KAM, Michie PT, Todd J. Paying attention to MMN in schizophrenia. Brain Res 2015; 1626:267-79. [PMID: 26163366 DOI: 10.1016/j.brainres.2015.06.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 05/29/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
Abstract
The aim of this review is to explore the phenomenon of reduced mismatch negativity (MMN) in persons with schizophrenia and the possible relationship it has with attention impairments. In doing so we discuss (i) the prediction error account of MMN, (ii) reduced MMN as a faulty predictive processing system in persons with schizophrenia, (iii) the role of these systems in relevance filtering and attentional resource protection, (iv) attentional impairments in persons with schizophrenia, and (v) research that has explored MMN and attention in schizophrenia groups. Our review of the literature suggests that no study has appropriately examined the functional impact of smaller MMN in schizophrenia on the performance of a concurrent attention task. We conclude that future research should explore this notion further in the hope that it might embed MMN findings within outcomes of functional significance to individuals with the illness and those providing treatment. This article is part of a Special Issue entitled SI: Prediction and Attention.
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Affiliation(s)
- Karlye A M Damaso
- School of Psychology, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre for Translational Neuroscience and Mental Health, University of Newcastle, Callaghan, NSW, Australia
| | - Patricia T Michie
- School of Psychology, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre for Translational Neuroscience and Mental Health, University of Newcastle, Callaghan, NSW, Australia; Schizophrenia Research Institute, Sydney, NSW, Australia
| | - Juanita Todd
- School of Psychology, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre for Translational Neuroscience and Mental Health, University of Newcastle, Callaghan, NSW, Australia; Schizophrenia Research Institute, Sydney, NSW, Australia.
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6
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Ikeda C, Kirino E, Inoue R, Arai H. Event-related potential study of illusory contour perception in schizophrenia. Neuropsychobiology 2012; 64:231-8. [PMID: 21912192 DOI: 10.1159/000327706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 03/20/2011] [Indexed: 11/19/2022]
Abstract
Schizophrenic patients and healthy controls participated in event-related potential experiments, in which illusory contour (IC) and control objects [no contour (NC), real contour (RC)] were passively presented. As a result, P100 latency for IC in schizophrenic patients was significantly prolonged (+10.6 ms) compared to those for RC. The present findings indicate that an abnormality of IC processing, including 'bottom-up' as well as 'top-down' processing, may reflect basal pathogenesis of various clinical representations of schizophrenia. However, the P100 latency difference between IC and RC was very small in the patient group. Rather, 'cognitive' in the Positive and Negative Syndrome Scale (PANSS) model of Bell et al. significantly correlated with P100 latencies for NC. Such an association between PANSS and NC processing, where the shape must be inferred with increased attentional demands and 'top-down' processing, indicates that the abnormality of schizophrenic patients' preattentive process might be a problem of 'top-down' processing rather than 'bottom-up' processing.
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Affiliation(s)
- Chisako Ikeda
- Department of Psychiatry, Juntendo University School of Medicine, Koshigaya, Japan
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7
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Elahipanah A, Christensen BK, Reingold EM. Attentional guidance during visual search among patients with schizophrenia. Schizophr Res 2011; 131:224-30. [PMID: 21741215 DOI: 10.1016/j.schres.2011.05.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 05/24/2011] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
Abstract
The current study investigated visual guidance and saccadic selectivity during visual search among patients with schizophrenia (SCZ). Data from a previous study (Elahipanah, A., Christensen, B.K., & Reingold, E.M., 2008. Visual selective attention among persons with schizophrenia: The distractor ratio effect. Schizophr. Res. 105, 61-67.) suggested that visual guidance for the less frequent distractors in a conjunction search display (i.e., the distractor ratio effect) is intact among SCZ patients. The current study investigated the distractor ratio effect among SCZ patients when: 1) search is more demanding, and 2) search involves motion perception. In addition, eye tracking was employed to directly study saccadic selectivity for the different types of distractors. Twenty-eight SCZ patients receiving a single antipsychotic medication and 26 healthy control participants performed two conjunction search tasks: a within-dimension (i.e., colour × colour) search task; and a cross-dimension (i.e., motion × colour) search task. In each task the relative frequency of distractors was manipulated across 5 levels. Despite slower search times, patients' eye movement data indicated unimpaired visual guidance in both tasks. However, in the motion × colour conjunction search task, patients displayed disproportionate difficulty detecting the moving target when the majority of distractors were also moving. Results demonstrate that bottom-up attentional guidance is unimpaired among patients with SCZ; however, patients' impairment in motion discrimination impedes their ability to detect a moving target against noisy backgrounds.
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Abstract
Working memory impairment is considered a core deficit in schizophrenia, but the precise nature of this deficit has not been determined. Multiple lines of evidence implicate deficits at the encoding stage. During encoding, information is held in a precategorical sensory store termed iconic memory, a literal image of the stimulus with high capacity but rapid decay. Pathologically increased iconic decay could reduce the number of items that can be transferred into working memory before the information is lost and could thus contribute to the working memory deficit seen in the illness. The current study used a partial report procedure to test the hypothesis that patients with schizophrenia (n = 37) display faster iconic memory decay than matched healthy control participants (n = 28). Six letters, arranged in a circle, were presented for 50 ms. Following a variable delay of 0-1000 ms, a central arrow cue indicated the item to be reported. In both patients and control subjects, recall accuracy decreased with increasing cue delay, reflecting decay of the iconic representation of the stimulus array. Patients displayed impaired memory performance across all cue delays, consistent with an impairment in working memory, but the rate of iconic memory decay did not differ between patients and controls. This provides clear evidence against faster loss of iconic memory representations in schizophrenia, ruling out iconic decay as an underlying source of the working memory impairment in this population. Thus, iconic decay rate can be added to a growing list of unimpaired cognitive building blocks in schizophrenia.
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Affiliation(s)
- Britta Hahn
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA.
| | - Emily S. Kappenman
- Center for Mind and Brain and Department of Psychology, University of California, Davis, CA 95618
| | - Benjamin M. Robinson
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228
| | - Rebecca L. Fuller
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228
| | - Steven J. Luck
- Center for Mind and Brain and Department of Psychology, University of California, Davis, CA 95618
| | - James M. Gold
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228
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9
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What can eye movements tell us about Symbol Digit substitution by patients with schizophrenia? Schizophr Res 2011; 127:137-43. [PMID: 21147521 DOI: 10.1016/j.schres.2010.11.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 11/08/2010] [Accepted: 11/12/2010] [Indexed: 11/22/2022]
Abstract
Substitution tests are sensitive to cognitive impairment and reliably discriminate patients with schizophrenia from healthy individuals better than most other neuropsychological instruments. However, due to their multifaceted nature, substitution test scores cannot pinpoint the specific cognitive deficits that lead to poor performance. The current study investigated eye movements during performance on a substitution test in order to better understand what aspect of substitution test performance underlies schizophrenia-related impairment. Twenty-five patients with schizophrenia and 25 healthy individuals performed a computerized version of the Symbol Digit Modalities Test while their eye movements were monitored. As expected, patients achieved lower overall performance scores. Moreover, analysis of participants' eye movements revealed that patients spent more time searching for the target symbol every time they visited the key area. Patients also made more visits to the key area for each response that they made. Regression analysis suggested that patients' impaired performance on substitution tasks is primarily related to a less efficient visual search and, secondarily, to impaired memory.
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10
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Visuo-perceptual organization and working memory in patients with schizophrenia. Neuropsychologia 2010; 49:435-43. [PMID: 21167849 DOI: 10.1016/j.neuropsychologia.2010.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 11/22/2010] [Accepted: 12/09/2010] [Indexed: 11/22/2022]
Abstract
We explore the mechanisms sub-tending the re-organization and memorization of visual information by studying how these mechanisms fail in patients with schizophrenia. Several studies have suggested that patients have difficulties in organizing information in perception and memory. We explore to what extent prompting patients to group items influences memory performance. We distinguish automatic grouping from top-down grouping processes, which are especially involved in re-organizing information. The main task was to memorize pairs of figures. Following manipulation of proximity, pairs of figures were part of the same perceptual group (within-group pair, formed on the basis of automatic grouping) or belonged to different groups (between-group pairs, re-grouped through top-down processes). Prior to the memory task, subjects ran a perception task prompting them to prioritize either within-group or between-group pairs. Unlike patients, controls globally benefited from grouping by proximity in the memory task. In addition, the results showed that prioritizing between-group pairs had a deleterious effect in patients, but with a large decrement in memory performance in the case of within-group rather than between-group figures. This occurred despite preserved focalization on within-group figures, as shown by eye-movement recordings. The suggestion is that when patients are prompted to re-group separate items, they can do so, but the benefit derived from automatic grouping is then not only lost but also reversed. This suggests re-organizing visual information not only involves re-grouping separate items but also integrating these new groups in a unified representation, which is impaired in patients with schizophrenia.
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Müller-Plath G, Ott DVM, Pollmann S. Deficits in subprocesses of visual feature search after frontal, parietal, and temporal brain lesions--a modeling approach. J Cogn Neurosci 2010; 22:1399-424. [PMID: 19445605 DOI: 10.1162/jocn.2009.21275] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Deficits in visuospatial attention are commonly observed after different kinds of brain lesions. However, the structure-function relationships are not well understood. We investigated whether our response time (RT) model, strategies of visual search (STRAVIS), combined with a linear model of brain lesions, enables us to relate specific impairments in cognitive processes to specific sites of focal brain lesions. In STRAVIS, RTs in overt visual feature search with graded target-distractor similarity are decomposed into the durations of successive search steps. Fitting the model to an observer's RTs yields individual estimates of the parameters "attentional focus size," "attentional dwell time," and "movement time of attention or the eyes." In 28 patients with various focal lesions to the frontal, parietal, and/or temporal cortex and 28 matched controls, we determined with the help of linear models which lesions were most predictive for each parameter. Predictions were validated with a second sample of 12 patients and 12 controls. Critical lesion areas for the STRAVIS focus size were the dorsolateral prefrontal cortex and the temporal lobe, with dorsolateral prefrontal cortex lesions reducing the focus and temporal lesions enlarging it. The STRAVIS dwell time was reduced in patients with lesions to the anterior insula and the superior parietal lobe. Lesions to the frontal eye fields, the superior parietal lobe, and the parieto-occipital cortex were most detrimental to the STRAVIS movement time. Applying linear models to a patient sample with heterogeneous lesions may be a promising new method for investigating how different brain areas interplay in a complex task.
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12
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Scholes KE, Martin-Iverson MT. Disturbed prepulse inhibition in patients with schizophrenia is consequential to dysfunction of selective attention. Psychophysiology 2010; 47:223-35. [DOI: 10.1111/j.1469-8986.2009.00927.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Silverstein SM, Keane BP. Perceptual organization in schizophrenia: Plasticity and state-related change. ACTA ACUST UNITED AC 2009. [DOI: 10.1556/lp.1.2009.2.111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Examining the effects of two factors on working memory maintenance of bound information in schizophrenia. J Int Neuropsychol Soc 2009; 15:597-605. [PMID: 19573278 DOI: 10.1017/s1355617709090833] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Integrating information in space and time is a central feature of episodic memory. Although disturbance of the binding processes in episodic memory is well established in patients with schizophrenia, data on working memory (WM) remain discrepant. In a change detection procedure, two target displays of pairs of letters located in cells of grid were successively presented. Participants attempted to detect changes in binding information (i.e., recombination of studied features) or feature information (i.e., a novel letter and/or a novel spatial location). Recombinations consisted of features belonging to the same display (intradisplay) or different displays (interdisplays). Results showed that patients demonstrated overall lower performance, with no specific deficit for recognizing bound information or feature information. In addition, patients did not demonstrate deficits for interdisplay recombinations or intradisplay recombinations. Patients' ability to remember temporal occurrence of stimuli was not affected. Together, these results suggest that in patients with schizophrenia, binding processes in WM are not specifically disturbed.
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Abstract
The construct of attention has many facets that have been examined in human and animal research and in healthy and psychiatrically disordered conditions. The Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) group concluded that control of attention-the processes that guide selection of task-relevant inputs-is particularly impaired in schizophrenia and could profit from further work with refined measurement tools. Thus, nominations for cognitive tasks that provide discrete measures of control of attention were sought and were then evaluated at the third CNTRICS meeting for their promise for future use in treatment development. This article describes the 5 nominated measures and their strengths and weaknesses for cognitive neuroscience work relevant to treatment development. Two paradigms, Guided Search and the Distractor Condition Sustained Attention Task, were viewed as having the greatest immediate promise for development into tools for treatment research in schizophrenia and are described in more detail by their nominators.
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Affiliation(s)
- Keith H. Nuechterlein
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, 300 UCLA Medical Plaza, Room 2240, Los Angeles, CA 90095-6968,Department of Psychology, University of California, Los Angeles,To whom correspondence should be addressed; tel: 310-825-0036, fax: 310-206-3651, e-mail:
| | - Steven J. Luck
- Center for Mind and Brain, University of California, Davis,Department of Psychology, University of California, Davis
| | - Cindy Lustig
- Department of Psychology, University of Michigan
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Visual selective attention among persons with schizophrenia: the distractor ratio effect. Schizophr Res 2008; 105:61-7. [PMID: 18579345 DOI: 10.1016/j.schres.2008.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/26/2008] [Accepted: 05/01/2008] [Indexed: 11/23/2022]
Abstract
The current study investigated whether impaired visual attention among patients with schizophrenia can be accounted for by poor perceptual organization and impaired search selectivity. Twenty-three patients with schizophrenia and 22 healthy control participants completed a conjunctive visual search task where the relative frequency of the two types of distractors was manipulated. It has been shown that, when the total number of items in a display is fixed, search performance depends on the relative frequency of the types of distractors (i.e., as the ratio becomes more discrepant search time decreases). This modulation of search efficiency reflects participants' ability to group items by their perceptual similarity and then search only the smaller group of items that share a feature with the target. Results show that patients modulate their response time normally as a function of the distractor ratio--that is, they benefit from the presence of a smaller distractor subset in the display. This suggests that patients with schizophrenia, group items according to their perceptual similarity and flexibly deploy their attention to the smaller subset of distractors on each trial. These results demonstrate that search selectivity as a function of the relative frequency of distractors is unimpaired among patients with schizophrenia.
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17
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Brodeur M, Pelletier M, Lepage M. Seeing is remembering: do deficits in closure affect visual memory recognition in schizophrenia? Cogn Neuropsychiatry 2008; 13:385-405. [PMID: 18781493 DOI: 10.1080/13546800802341047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Episodic memory is significantly impaired in people with schizophrenia. The precise cause of this impairment has yet to be determined, as the formation of episodic memories is dependent on other processes, some of which also show impairment in schizophrenia. One such process is closure, that is, the filling-in of missing information. Failure to close adequately incomplete stimuli may cause people with schizophrenia to store inadequate or piecemeal representations in memory. METHODS Forty people with schizophrenia and 21 healthy comparison subjects participated in the study. The experiment was divided into six blocks, each of which involved both an encoding and a recognition phase. During the encoding phase, 20 figures were presented sequentially and participants had to determine whether each was symmetric or asymmetric. These figures were either complete or fragmented at three different levels. In subsequent recognition phase, 40 abstract figures (20 new and 20 old) were presented. All figures were complete in this phase. RESULTS Memory performance of both groups was affected similarly by fragmentation, with an additional increase in performance afforded by a slight fragmentation for participants with schizophrenia. CONCLUSION Slight fragmentation may have induced a perceptual difficulty that was mild enough to increase visual processing without compromising it. Closure was thus not involved in the episodic memory deficit of people with schizophrenia.
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Affiliation(s)
- M Brodeur
- Douglas Mental Health University Institute, Verdun, Quebec, Canada
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18
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Abstract
Many cognitive tasks have been developed by basic scientists to isolate and measure specific cognitive processes in healthy young adults, and these tasks have the potential to provide important information about cognitive dysfunction in psychiatric disorders, both in psychopathology research and in clinical trials. However, several practical and conceptual challenges arise in translating these tasks for patient research. Here we outline a paradigm development strategy--which involves iteratively testing modifications of the tasks in college students, in older healthy adults, and in patients--that we have used to successfully translate a large number of cognitive tasks for use in schizophrenia patients. This strategy makes it possible to make the tasks patient friendly while maintaining their cognitive precision. We also outline several measurement issues that arise in these tasks, including differences in baseline performance levels and speed-accuracy trade-offs, and we provide suggestions for addressing these issues. Finally, we present examples of 2 experiments, one of which exemplifies our recommendations regarding measurement issues and was a success and one of which was a painful but informative failure.
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Affiliation(s)
- Steven J. Luck
- Center for Mind & Brain and Department of Psychology, University of California, Davis,To whom correspondence should be addressed; UC-Davis Center for Mind & Brain, 267 Cousteau Place, Davis, CA 95618; tel: +1-530-297-4424, fax: +1-530-297-4400, e-mail:
| | - James M. Gold
- Department of Pshychiatry, University of Maryland School of Medicine, Maryland Psychiatric Research Center Baltimore, MD
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Cocchi L, Schenk F, Volken H, Bovet P, Parnas J, Vianin P. Visuo-spatial processing in a dynamic and a static working memory paradigm in schizophrenia. Psychiatry Res 2007; 152:129-42. [PMID: 17512986 DOI: 10.1016/j.psychres.2006.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 12/23/2005] [Accepted: 02/05/2006] [Indexed: 10/23/2022]
Abstract
Recent findings suggest that the visuo-spatial sketchpad (VSSP) may be divided into two sub-components processing dynamic or static visual information. This model may be useful to elucidate the confusion of data concerning the functioning of the VSSP in schizophrenia. The present study examined patients with schizophrenia and matched controls in a new working memory paradigm involving dynamic (the Ball Flight Task - BFT) or static (the Static Pattern Task - SPT) visual stimuli. In the BFT, the responses of the patients were apparently based on the retention of the last set of segments of the perceived trajectory, whereas control subjects relied on a more global strategy. We assume that the patients' performances are the result of a reduced capacity in chunking visual information since they relied mainly on the retention of the last set of segments. This assumption is confirmed by the poor performance of the patients in the static task (SPT), which requires a combination of stimulus components into object representations. We assume that the static/dynamic distinction may help us to understand the VSSP deficits in schizophrenia. This distinction also raises questions about the hypothesis that visuo-spatial working memory can simply be dissociated into visual and spatial sub-components.
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Affiliation(s)
- Luca Cocchi
- Institute of Sport science and physical education, Lausanne, Switzerland.
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20
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Gold JM, Fuller RL, Robinson BM, Braun EL, Luck SJ. Impaired top-down control of visual search in schizophrenia. Schizophr Res 2007; 94:148-55. [PMID: 17544632 PMCID: PMC1978542 DOI: 10.1016/j.schres.2007.04.023] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 04/20/2007] [Accepted: 04/24/2007] [Indexed: 11/24/2022]
Abstract
This study examined top-down and bottom-up control of attention in a group of 24 patients with schizophrenia and 16 healthy volunteers. Participants completed a visual search task in which they reported whether a target oval contained a gap. The target was accompanied by 5, 11, or 17 distractors. On some trials, the target was identified by a highly salient feature that was shared by only 2 distractors, causing this feature to "pop out" from the display. This feature provided strong bottom-up information that could be used to direct attention to the target. On other trials, half of the distractors contained this feature making these distractors no more salient than the other distractors requiring greater use of top-down control to restrict processing to items containing this feature. Patient visual search efficiency closely approximated control performance in the first trial type. In contrast, patients demonstrated significant slowing of search in the second trial type, which required top-down control. These results suggest that schizophrenia does not impair the ability to implement the selection of a target when attention can be guided by bottom-up information, but it does impair the ability to use top-down control mechanisms to guide attention. These results extend prior studies that have focused on aspects of executive control in complex tasks and suggest that a similar underlying deficit may also impact the performance of perceptual systems.
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Affiliation(s)
- James M Gold
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, PO Box 21247, Baltimore, Maryland 21228, United States.
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21
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Ravizza SM, Robertson LC, Carter CS, Nordahl TE, Salo RE. Is filtering difficulty the basis of attentional deficits in schizophrenia? Psychiatry Res 2007; 151:201-9. [PMID: 17399801 DOI: 10.1016/j.psychres.2006.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 08/21/2006] [Accepted: 12/04/2006] [Indexed: 11/20/2022]
Abstract
The distractibility that schizophrenia patients display may be the result of a deficiency in filtering out irrelevant information. The aim of the current study was to assess whether patients with schizophrenia exhibit greater difficulty when task-irrelevant features change compared to healthy participants. Thirteen medicated outpatients with a diagnosis of schizophrenia and thirteen age- and parental education-matched controls performed a target selection task in which the task-relevant letter or the task-irrelevant features of color, and/or location repeated or switched. Participants were required to respond by pressing the appropriate key associated with the target letter. These patients with schizophrenia were slower when the task-relevant target letter switched than when it repeated. In contrast, schizophrenia patients performed similarly to controls when task-irrelevant information changed. Thus, we found no evidence that patients with schizophrenia were impaired in inhibiting irrelevant perceptual features. In contrast, changes in task-relevant features were problematic for patients relative to control participants. These results suggest that medicated outpatients who are mild to moderately symptomatic do not exhibit global impairments of feature processing. Instead, impairments are restricted to situations when task-relevant features vary. The current findings also suggest that when a course of action is not implied by an irrelevant feature, outpatients' behavior is not modulated by extraneous visual information any more than in healthy controls.
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Affiliation(s)
- Susan M Ravizza
- Department of Psychology, University of California, Davis, CA, USA.
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22
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Tanaka G, Mori S, Inadomi H, Hamada Y, Ohta Y, Ozawa H. Clear distinction between preattentive and attentive process in schizophrenia by visual search performance. Psychiatry Res 2007; 149:25-31. [PMID: 17123633 DOI: 10.1016/j.psychres.2006.01.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 10/17/2005] [Accepted: 01/17/2006] [Indexed: 11/26/2022]
Abstract
Visual information-processing deficits were investigated in patients with schizophrenia using visual search tasks. Subjects comprised 20 patients with schizophrenia and 20 normal subjects. Visual search tasks were modified from those used previously to reveal more distinct differences between feature and conjunction search tasks. The presentation area of items in the present study was more than double the area used in our previous study [Mori, S., Tanaka, G., Ayaka, Y., Michitsuji, S., Niwa, H., Uemura, M., Ohta, Y., 1996. Preattentive and focal attentional processes in schizophrenia: a visual search study. Schizophrenia Research 22, 69-76], and items were distributed over the area randomly in each trial to produce a certain range of locational jitter for each item across trials that prevented a matrix-like presentation of items at fixed positions [Mori, S., Tanaka, G., Ayaka, Y., Michitsuji, S., Niwa, H., Uemura, M., Ohta, Y., 1996. Preattentive and focal attentional processes in schizophrenia: a visual search study. Schizophrenia Research 22, 69-76]. The target was a red square, and distractors were red circles in the feature search task and red circles and green squares in the conjunction search task. Slopes and intercepts of a linear function relating reaction times to set size were computed. In the feature search task, slopes for both groups were almost zero. In the conjunction search task, significant differences in slopes were seen between the two groups irrespective of target presence or absence. Moreover, the slopes were approximately twice as steep during target absence as during target presence. These results indicate more definitively than the results of our previous study [Mori, S., Tanaka, G., Ayaka, Y., Michitsuji, S., Niwa, H., Uemura, M., Ohta, Y., 1996. Preattentive and focal attentional processes in schizophrenia: a visual search study. Schizophrenia Research 22, 69-76] that patients with schizophrenia have deficits in focal attentional processing, although their preattentive processing functions at a normal level.
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Affiliation(s)
- Goro Tanaka
- Department of Occupational Therapy, School of Health Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8520, Japan.
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Fuller RL, Luck SJ, Braun EL, Robinson BM, McMahon RP, Gold JM. Impaired control of visual attention in schizophrenia. JOURNAL OF ABNORMAL PSYCHOLOGY 2006; 115:266-75. [PMID: 16737391 DOI: 10.1037/0021-843x.115.2.266] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To investigate attentional impairment in schizophrenia, the authors examined the performance of 22 patients with schizophrenia and 16 healthy control subjects in 4 visual search tasks that varied in perceptual requirements and in the need for precise attentional control. The rate of search was slowed in the patients in all tasks. However, the degree of slowing was largest in tasks requiring precise attentional control and smallest in tasks that were perceptually difficult but required less attentional control. This pattern of results indicates that the primary impairment of attention in schizophrenia lies in the control of attention and not in the selection processes that operate once attention has been directed to an object.
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Affiliation(s)
- Rebecca L Fuller
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228, USA.
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24
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Luck SJ, Fuller RL, Braun EL, Robinson B, Summerfelt A, Gold JM. The speed of visual attention in schizophrenia: electrophysiological and behavioral evidence. Schizophr Res 2006; 85:174-95. [PMID: 16713184 DOI: 10.1016/j.schres.2006.03.040] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 03/21/2006] [Accepted: 03/24/2006] [Indexed: 10/24/2022]
Abstract
Schizophrenia is characterized by a substantial slowing of manual response times and by impairments in attention. However, prior research has not investigated whether attention itself is slowed in schizophrenia, and this was the goal of the present study. In Experiment 1, the N2pc component of the event-related potential waveform-an electrophysiological correlate of the focusing of attention-was recorded from 24 schizophrenia spectrum patients and 13 control subjects. Although behavioral response times were delayed by over 100 ms in the patient group, the onset latency of the N2pc component was virtually identical across groups, and no reduction in N2pc amplitude was observed in the patient group. In Experiment 2, a new cueing paradigm was developed to provide a behavioral measure of the speed of attention in 22 schizophrenia spectrum patients and 13 control subjects. We found that the average time required to allocate attention to a cued location was only 19 ms greater for the patient group than for the control group, with most patients within the range of the control subjects. Together, these experiments revealed little or no slowing of the allocation of visual-spatial attention in patients with schizophrenia. Thus, the mechanisms responsible for allocating attention to salient visual targets appear to be largely unaffected by the illness, and the well documented slowing of manual response times in schizophrenia cannot easily be explained by a slowing of attention.
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Affiliation(s)
- Steven J Luck
- Department of Psychology, University of Iowa, Iowa City, 52242-1407, USA.
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25
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Lee J, Park S. The role of stimulus salience in CPT-AX performance of schizophrenia patients. Schizophr Res 2006; 81:191-7. [PMID: 16226875 DOI: 10.1016/j.schres.2005.08.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 08/09/2005] [Accepted: 08/15/2005] [Indexed: 10/25/2022]
Abstract
CPT-AX performance deficit in schizophrenia is well documented but it is unclear what causes this impairment. Past studies have focused on the roles of sustained attention and context processing in CPT-AX but the role of working memory (WM) has not been fully examined even though encoding and maintenance of the cue in WM may be critical to CPT-AX. The major goal of this study was to investigate the effects of stimulus encoding in WM on CPT-AX. Encoding was manipulated by presenting different colored (i.e., salient) cue stimuli on 20% of the trials. WM maintenance was manipulated by varying the cue-target interstimulus interval (ISI). A control task (CPT-Single) that does not require WM but assesses sustained attention was also administered. Schizophrenia patients (SZ) were impaired compared with normal controls (CO) on the CPT-AX overall but not in CPT-Single. For both groups, CPT-AX accuracy improved on salient cue trials in the long ISI condition. In the short ISI condition, where accuracy was already high, the cue saliency effect was observed in the faster RT and SZ benefited significantly more than CO. The effect of target salience was not observed in the CPT-Single, which assesses sustained attention. These results suggest that the facilitation of WM encoding by enhancing cue salience may be a key to improving CPT-AX performance.
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Affiliation(s)
- Junghee Lee
- Department of Psychology and The Center for Integrative and Cognitive Neuroscience, Vanderbilt University, 111 21st Ave. South, Nashville, TN 37240, USA.
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26
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Uhlhaas PJ, Silverstein SM. Perceptual Organization in Schizophrenia Spectrum Disorders: Empirical Research and Theoretical Implications. Psychol Bull 2005; 131:618-632. [PMID: 16060805 DOI: 10.1037/0033-2909.131.4.618] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The research into perceptual organization in schizophrenia spectrum disorders has found evidence for and against a perceptual organization deficit and has interpreted the data from within several different theoretical frameworks. A synthesis of this evidence, however, reveals that this body of work has produced reliable evidence for deficits in schizophrenia, as well as for the clinical, stimulus, and task parameters associated with normal and abnormal performance. Recent models of cognition have also advanced understanding of the underlying pathophysiological processes of perceptual organization dysfunction in schizophrenia spectrum disorders. These suggest that deficits in perceptual organization may be one manifestation of a wider disturbance in the integration of contextually related information across space and time.
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27
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Tsakanikos E. Latent inhibition, visual pop-out and schizotypy: is disruption of latent inhibition due to enhanced stimulus salience? PERSONALITY AND INDIVIDUAL DIFFERENCES 2004. [DOI: 10.1016/j.paid.2004.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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28
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Working memory for visual features and conjunctions in schizophrenia. JOURNAL OF ABNORMAL PSYCHOLOGY 2003. [DOI: 10.1037/0021-843x.112.1.61] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Alain C, Bernstein LJ, He Y, Cortese F, Zipursky RB. Visual feature conjunction in patients with schizophrenia: an event-related brain potential study. Schizophr Res 2002; 57:69-79. [PMID: 12165377 DOI: 10.1016/s0920-9964(01)00303-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The neural mechanisms supporting performance during single feature and feature conjunction detection were investigated in patients with schizophrenia and age-matched controls using event-related brain potentials. In different blocks of trials, participants responded to visual targets defined by one of two colors, one of two orientations, or both color and orientation. All participants were faster and more accurate in detecting targets defined by a single feature than for targets defined by a conjunction of features. Relative to controls, patients made more errors and were slower in detecting targets defined by a combination of features. Patients also generated a smaller N2 wave to single and conjunctive targets, and showed greater P3b reduction over the right hemisphere for conjunctive targets than for targets defined by color only. In addition, target stimuli generated an increased negativity at the occipital sites that varied in scalp distribution with the attended features in controls but not in patients. Both behavioral and electrophysiological data provide converging evidence for deficits in integrating visual features in schizophrenia and suggest that processing features of visual objects in schizophrenia are partly supported by distinct functional networks.
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Affiliation(s)
- Claude Alain
- Rotman Research Institute, Baycrest Centre for Geriatric Care, 3560 Bathurst Street, Toronto, ON, Canada M6A 2E1.
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Carr VJ, Dewis SA, Lewin TJ. Illusory conjunctions and perceptual grouping in a visual search task in schizophrenia. Psychiatry Res 1998; 80:69-81. [PMID: 9727965 DOI: 10.1016/s0165-1781(98)00050-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This report describes part of a series of experiments, conducted within the framework of feature integration theory, to determine whether patients with schizophrenia show deficits in preattentive processing. Thirty subjects with a DSM-III-R diagnosis of schizophrenia and 30 age-, gender-, and education-matched normal control subjects completed two computerized experimental tasks, a visual search task assessing the frequency of illusory conjunctions (i.e. false perceptions) under conditions of divided attention (Experiment 3) and a task which examined the effects of perceptual grouping on illusory conjunctions (Experiment 4). We also assessed current symptomatology and its relationship to task performance. Contrary to our hypotheses, schizophrenia subjects did not show higher rates of illusory conjunctions, and the influence of perceptual grouping on the frequency of illusory conjunctions was similar for schizophrenia and control subjects. Nonetheless, specific predictions from feature integration theory about the impact of different target types (Experiment 3) and perceptual groups (Experiment 4) on the likelihood of forming an illusory conjunction were strongly supported, thereby confirming the integrity of the experimental procedures. Overall, these studies revealed no firm evidence that schizophrenia is associated with a preattentive abnormality in visual search using stimuli that differ on the basis of physical characteristics.
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Affiliation(s)
- V J Carr
- Discipline of Psychiatry, Faculty of Medicine and Health Sciences, University of Newcastle, Callaghan, NSW, Australia.
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