Late, not early, stages of Kanizsa shape perception are compromised in schizophrenia

NEUROPSYCHOLOGIA

卷:56

Article

Keane, Brian P.^1,2,3  Joseph, Jamie^2,4  Silverstein, Steven M.^1,2 

[1] Rutgers Robert Wood Johnson Med Sch, Piscataway, NJ 08854 USA

[2] Rutgers Univ Behav Hlth Care, Piscataway, NJ 08854 USA

[3] Rutgers State Univ, Ctr Cognit Sci, Piscataway, NJ 08854 USA

[4] Rutgers State Univ, Grad Sch Biomed Sci, Piscataway, NJ 08854 USA

关键词: Illusory contours;    Kanizsa shape perception;    Visual completion;    Schizophrenia;    Conceptual disorganization;    Thought disorder;   

DOI  :  10.1016/j.neuropsychologia.2014.02.001

来源: Elsevier

【 摘 要 】

Background: Schizophrenia is a devastating psychiatric disorder characterized by symptoms including delusions, hallucinations, and disorganized thought. Kanizsa shape perception is a basic visual process that builds illusory contour and shape representations from spatially segregated edges. Recent studies have shown that schizophrenia patients exhibit abnormal electrophysiological signatures during Kanizsa shape perception tasks, but it remains unclear how these abnormalities are manifested behaviorally and whether they arise from early or late levels in visual processing. Method: To address this issue, we had healthy controls and schizophrenia patients discriminate quartets of sectored circles that either formed or did not form illusory shapes (illusory and fragmented conditions, respectively). Half of the trials in each condition incorporated distractor lines, which are known to disrupt illusory contour formation and thereby worsen illusory shape discrimination. Results: Relative to their respective fragmented conditions, patients performed worse than controls in the illusory discrimination. Conceptually disorganized patients characterized by their incoherent manner of speaking were primarily driving the effect. Regardless of patient status or disorganization levels, distractor lines worsened discrimination more in the illusory than the fragmented condition, indicating that all groups could form illusory contours. Conclusion: People with schizophrenia form illusory contours but are less able to utilize those contours to discern global shape. The impairment is especially related to the ability to think and speak coherently. These results suggest that Kanizsa shape perception incorporates an early illusory contour formation stage and a later, conceptually-mediated shape integration stage, with the latter being compromised in schizophrenia. (C) 2014 Elsevier Ltd. All rights reserved.

【 授权许可】

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