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Updated: Jun 24, 2026

Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior
Published on: April 16, 2014
Attentional modulation of perceptual organisation in schizophrenia
Szabolcs Kéri1, Oguz Kelemen, György Benedek
1Semmelweis University, Department of Psychiatry and Psychotherapy, Budapest, Hungary. keriszabolcs@psych.sote.hu
Introduction:
Previous studies indicated impaired perceptual organisation in schizophrenia. This study investigated lateral connection and attentional modulation in early visual cortex of schizophrenia patients.
Methods:
Contrast threshold was measured for a central Gabor patch, flanked with orthogonal and collinear Gabor patches. In the attended condition, participants performed a concurrent vernier task by determining the spatial offset of the flankers.
Results:
The controls (n=25) had lower contrast thresholds in the collinear condition than in the orthogonal condition, whereas the schizophrenia patients (n=43) did not benefit from the presence of collinear flankers. This deficit was not ameliorated by attentional modulation. Antipsychotic medication did not affect the performance.
Conclusions:
These results suggest that lateral connections are impaired in early visual cortex of schizophrenia patients. This deficit cannot be restored by top-down attentional modulation of target-flanker interactions.
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