| The study of emotional learning and memory has garnered significant interest in recent years for its clinical relevance to psychiatric disorders. While fear is an evolutionarily adaptive response, aberrant regulation of fear learning and emotional memories can result in debilitating forms of anxiety and post-traumatic stress disorder (PTSD), in which fears are experienced long after a threat has passed. Highly conserved neural circuitry between rodents and humans has allowed for in-depth characterization of behavioral and molecular processes associated with emotional learning and memory. In light of these advances, and in effort to enhance experimental control, the systems mediating fear learning and aversive memory are often portrayed as oversimplified, closed circuits, consisting of one or two isolated brain regions, rendering the concept of complex interactions between multiple brain regions absent from a majority of existing literature. To further complicate the understanding of the already complex neural circuitry implicated in fear and aversive learning, the brain is dynamically changing across development in both rodents and humans, and changes in structural and functional maturation have a significant impact on resulting neural processes and behaviors. In addition to developmental aspects, genetic variants in human populations and animal models can also profoundly impact neural substrates implicated in fear and anxiety, rendering specific populations more or less susceptible to developing psychiatric disorders at different stages of their lives.;This thesis seeks to understand normative developmental aspects of memory systems implicated in psychopathology of anxiety and post-traumatic stress disorders. A common single nucleotide polymorphism in brain-derived neurotrophic factor, BDNF Va166Met, is highlighted due its associated role in aberrant fear learning in both humans and animal models, as is the developmental transition into and out of adolescence, when anxiety and affective disorders are most prevalent in human populations. Collectively, the experiments outlined in this thesis suggest that targeting specific behavioral paradigms toward populations based on their genetic background and/or developmental stage, combined with the potential use of well-tailored pharmacological agents, may significantly advance individualized treatment options for anxiety and PTSD. |
