TitleNMDA receptor mediated expression of Arc in dorsal and ventral hippocampus contributes to the acquisition of contextual and trace fear conditioning
NameCzerniawski, Jennifer (author), Otto, Tim (chair), Shors, Tracey (internal member), McGann, John (internal member), Firestein, Bonnie (outside member), Rutgers University, Graduate School - New Brunswick,
DescriptionThe dorsal and ventral subregions of the hippocampus are differentially involved in several of types of learning, including fear conditioning. For example, we have previously demonstrated that the integrity of ventral, but not dorsal, hippocampus is necessary for the acquisition and expression of trace fear conditioning while dorsal, but not ventral, hippocampus is critically involved in spatially-guided reinforced alternation (Czerniawski, Yoon & Otto, 2009). In contrast to the partially dissociable effects of either lesions or inactivation, however, several lines of research suggest that, in intact subjects, both subregions are normally involved in the acquisition of many hippocampal-dependent tasks. The present studies investigated the molecular basis of these forms of learning by determining whether NMDA receptor-mediated immediate early gene expression in dorsal vs. ventral hippocampus contributes to the acquisition and/or retention of trace and contextual fear conditioning. In the first set of experiments we examined the effect of NMDA receptor antagonism in dorsal or ventral hippocampus on the acquisition or expression of trace and contextual fear conditioning. Next we assessed if trace fear conditioning alters the transcription and/or translation of Arc, an immediate early gene thought to be critically involved in some forms of plasticity and learning. In addition we examined the effect of blocking Arc translation with antisense oligodeoxynucleotides on the acquisition of CS-US associations in this paradigm. Lastly, in the final experiment we determined if the learning induced increase in Arc translation is NMDA receptor-dependent. The results of these studies suggest that both NMDA-receptor antagonism and the infusion of antisense oligodeoxynucleotides for the immediate early gene Arc (activity-regulated cytoskeletal protein) into dorsal or ventral hippocampus impair the acquisition of contextual and trace fear conditioning. In addition, trace fear conditioning enhances both Arc transcription and translation. Finally, pre-training infusions of either Arc antisense oligodeoxynucleotides or the NMDA receptor antagonist APV block the learning-induced enhancement of Arc. Together these studies support the notion that NMDA-receptor mediated expression of the immediate early gene Arc in both dorsal and ventral hippocampus may underlie the acquisition of a variety of forms of hippocampal dependent learning.
NoteIncludes bibliographical references
Noteby Jennifer Czerniawski
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.