The research of Pavlovian conditioning has elucidated much about the basic characteristics and neurobiology of animal memory. A simple associative memory can be formed and extinguished, but conditioned responding often returns following a variety of situations. These post-extinction re-emergences of conditioned behavior have been a point of interest for studying relapse in human disorders. There is a limited body of work that explains these opposing findings. Thus, the main aim of this dissertation is to further characterize the outcomes and neurobiology of reconditioning in a series of contextual fear conditioning experiments.