Declarative learning entails the internalization of facts and events. This type of learning depends on the integrity of the hippocampal system. In rodents, spatial learning is studied as a model of declarative learning. In this thesis, electrophysiological and behavioral experiments assessed the role of NMDA receptors in synaptic plasticity and rats' spatial learning and memory. Primed burst potentiation (PBP), a form of synaptic strengthening, was studied in freely-behaving rats treated with NMDA receptor antagonists. The impairments caused by the antagonists correlated with those observed in behavioral studies. The results support the idea that NMDA receptors in the hippocampal system mediate the internalization of the contents and organization of new environmental information, and show that the receptors are not relevant for spatial working memory or performance once a representation of the environment is stable. The results also suggest that stable spatial representations resemble multiple relations of events and do not correspond to topographical maps of an environment. As learning proceeds, representations are activated by smaller subsets of environmental cues, which eventually become sufficient for effective navigation. The representations thus are encoded as relationships of stimuli that share similarities or that are unique to a particular event. The organization of novel information is given through NMDA receptor-mediated synaptic plasticity. This plasticity mechanism could resemble a process similar to the synaptic changes observed during PBP.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.102737 |
| Date | January 2006 |
| Creators | Tirado Santiago, Giovanni. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Psychology.) |
| Rights | © Giovanni Tirado Santiago, 2006 |
| Relation | alephsysno: 002573805, proquestno: AAINR27849, Theses scanned by UMI/ProQuest. |
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