Grant: Discovery Grants Program - Individual

Abnormalities in identified learning and memory systems in the mammalian brain, changes in dynamic interactions between them, and alterations in interactions between these systems and other brain areas might mediate abnormal manifestations of thought and behaviour. Despite the potential explanatory power of this view, there are significant challenges that lie ahead including a general lack of information about the nature of these associations, the neural circuits involved, what kind of interactions occur between them, and the role of plasticity mechanisms in these processes. The current research proposal is directly interested in unraveling these complex brain processes by utilizing a breakthrough paradigm for assessing different types of memories acquired by different systems on the same task. The specific aims of this research program are threefold: 1) provide further evidence that the competitive interactions between these systems represent examples of a novel subclass of competitive interactions. This aim will be achieved by running retention and reversal experiments in which one of these neural structures will be damaged after acquisition of the task or a set of experiments using the post-training memory consolidation paradigm in which the hypothesized necessary versus incidental associations will be manipulated; 2) gain an understanding of the consequences of blocking NMDA plasticity in these systems at different times during training. This aim will be achieved by assessing the effects of post-training, localized NMDA (CPP) blockade in the dorsal striatum, amygdala, or hippocampus during acquisition of the visual discrimination task. 3) obtain information about the consequences of blocking new protein synthesis in these same systems at different times during training. Taken together, these experiments will give us a window into the dynamic and interactive nature of these neural systems with each other and provide important information about plasticity mechanisms supporting these complex brain functions and the localization of these processes.