NMDA Receptor Antagonist Ketamine Impairs Feature Integration in Visual Perception |
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| Authors: | Julia D. I. Meuwese Anouk M. van Loon H. Steven Scholte Philipp B. Lirk Nienke C. C. Vulink Markus W. Hollmann Victor A. F. Lamme |
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| Affiliation: | 1. Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.; 2. Cognitive Science Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands.; 3. Department of Anesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.; 4. Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.; Ecole Polytechnique Federale de Lausanne, Switzerland, |
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| Abstract: | Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA) receptors in monkeys can abolish neural signals related to figure-ground segregation and feature integration. However, it is unknown whether this also affects perceptual integration itself. Therefore, we tested whether ketamine, a non-competitive NMDA receptor antagonist, reduces feature integration in humans. We administered a subanesthetic dose of ketamine to healthy subjects who performed a texture discrimination task in a placebo-controlled double blind within-subject design. We found that ketamine significantly impaired performance on the texture discrimination task compared to the placebo condition, while performance on a control fixation task was much less impaired. This effect is not merely due to task difficulty or a difference in sedation levels. We are the first to show a behavioral effect on feature integration by manipulating the NMDA receptor in humans. |
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