Effects of Ketamine on perceptual grouping in rats.
Ketamine is a selective NMDA glutamate receptor antagonist that disrupts cognitive and behavioral function. Evidence exists that NMDA receptors play a role in lateral cortical connections, suggesting involvement in integrating information across the cortex. To investigate NMDA receptors' role in cortical integration at a perceptual level, psychophysical measures were made of perceptual grouping, which requires global analysis of neural representations of stimulus elements. Rats were trained to discriminate solid lines as well as patterns of dots that could be perceptually grouped into vertical or horizontal stripes. Psychophysical measures determined thresholds of perceptual grouping capacities. Rats receiving maximum subanesthetic doses of Ketamine discriminated solid patterns normally, but were impaired on dot pattern discrimination when greater demands were placed on perceptual grouping. These results demonstrate a selective disruption by Ketamine of visual discrimination that requires perceptual grouping of stimulus patterns. These results also provide evidence associating NMDA receptor-dependent neural mechanisms with context-dependent perceptual function.
Kurylo
Daniel D
DD
Department of Psychology, Brooklyn College CUNY, 2900 Bedford Avenue, Brooklyn, NY 11210, United States. dkurylo@brooklyn.cuny.edu
Gazes
Yunglin
Y
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D010364:Pattern Recognition, Visual / Q000187:drug effects*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D051381:Rats; D020318:Rats, Long-Evans; D012684:Sensory Thresholds / Q000187:drug effects
D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine