Abstract # 73:

Scheduled for Thursday, June 21, 2007 05:00 PM-07:00 PM: Session 7 (South Main Hall) Poster Presentation


S. E. Ward1 and D. J. Mandell2
1Washington National Primate Research Center and Infant Primate Research Laboratory, Box 357330, University of Washington , Seattle, WA 98195, USA, 2Department of Physiology and Pharmacology, Wake Forest University School of Medicine
     Association learning requires responding to stimuli based on the environmental context. A mature prefrontal cortex appears to be necessary for such cue-response learning. We studied the use of differential cues by 7 young (318 – 468 postnatal days) Macaca nemestrina tested on computerized conditional nonmatch and match to sample tasks. Animals were trained to a criterion of greater than 80% correct on a nonmatch rule paired with a grey background then switched to a match rule paired with a green background. Upon reaching match criterion, the monkeys were tested on both rules. The correct rule for each trial was cued by the background color of the screen. On the first day of testing, animals were significantly better on the match (80.7%) than the nonmatch rule [42.9%, t(6)=-4.22, p=0.006]. After three weeks of testing, this difference was no longer significant [match=68.3%, nonmatch=49.6%, t(6)=-1.56, p=0.17]. Five animals were able to respond to both rules with greater than chance performance but only 2 performed at the criteria of greater than 80% correct over the session and greater than 70% correct for each rule. The results show that young monkeys could distinguish between the environmental cues, but their ability to switch responses based on the cue was poor. Immature prefrontal functioning may have contributed to this limitation.