Hippocampal function and the developmental neurobiology of fear conditioning
University of Delaware
This dissertation investigates role of the hippocampus in the developmental neurobiology of fear conditioning. After an introduction to the developmental neurobiology of fear conditioning (Chapter 1), we examine the relative susceptibility of trace and context fear conditioning to post-natal interventions aimed at a restoration of hippocampal neuroanatomy following neonatal alcohol exposure (Chapter 2). We then examine Egr-1 mRNA expression patterns in the amygdala, hippocampus, and prefrontal cortex following variants of context fear learning in adolescent animals to examine the efficacy of this molecular marker of learning in developing animals (Chapter 3). Lastly, we empirically test whether trace fear conditioning in post-natal day 30 rats is hippocampus-dependent to substantiate previous claims that the development of this form of learning reflects hippocampal maturation (Chapter 4). These findings (summarized in Chapter 5), along with recent research on hippocampal physiology, set the foundation for an appraisal of the interaction between hippocampal and neocortical systems throughout development, and how this affects the sensitivity of learning paradigms to hippocampal insult (Chapter 6). These analyses will provide us with a more comprehensive and applicable model for the role of the hippocampus in learning both over the course of development and during adulthood.