NMDA receptor antagonist ketamine impairs feature integration in visual perception.
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.
Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands ; Cognitive Science Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands.
Julia D I
JD
Meuwese
Anouk M
AM
van Loon
H Steven
HS
Scholte
Philipp B
PB
Lirk
Nienke C C
NC
Vulink
Markus W
MW
Hollmann
Victor A F
VA
Lamme
D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007649:Ketamine / Q000009:adverse effects / Q000494:pharmacology*; D008297:Male; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D014796:Visual Perception / Q000187:drug effects*; D055815:Young Adult
D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine