UCLA

The study of memory is commonly associated with neuroscience, aging, education, andeyewitness testimony. This dissertation explores how eating behavior is also heavily intertwined—and yet considerably understudied in its relation to memory processes. Both are influenced by similar neuroendocrine signals (e.g., leptin and ghrelin) and are dependent on hippocampal functions. While learning processes have long been implicated in influencing eating behavior, recent research has shown how memory of recent eating modulates future consumption. In humans, obesity is associated with impaired memory performance, and in rodents, dietary-induced obesity causes rapid decrements to memory. Lesions to the hippocampus disrupt memory but also induce obesity, highlighting a cyclic relationship between obesity and memory impairment. In fact, the interconnected nature between learning and memory and eating may reflect the fact that learning and memory systems evolved primarily to aid in animals obtaining food. The chapters presented here explore this position and present evidence of unique “design features” of learning and memory systems that appear specialized for foraging. In Chapter 2, I show behavioral evidence consistent with innate metabolic responses to novel flavors—putatively because flavors have historically been reliable signals of incoming calories and because an inadequate metabolic response to flavors could be costly. In Chapter 3, I show enhanced memory of eating relative to other similar but noneating behaviors and prioritized memory for eating high-calorie relative to low-calorie foods. Finally, in Chapter 4, I explore the neural basis of backward conditioning, a historically overlooked phenomenon that might be critical in allowing animals to learn relationships between food outcomes and related cues that can guide future foraging behavior. Using a range of animal models and experimental techniques, these chapters elucidate the ways in which the recurring struggle to obtain food has profoundly shaped learning and memory systems.