Development and employment of discounting tasks in 16p11.2 hemideletion mice

Abstract

Humans must wait or make risky decisions to obtain different commodities of varying value. These decisions rely on learning the value of those commodities and adapting choices to maximize rewards while minimizing costs. As costs increase, humans discount the value of large costly rewards when a small, less costly option presents itself. The assessment of these cost-benefit analyses shifts according to individual factors such as sex and neurodivergence. It is then imperative to understand how different costs such as delay or probabilistic risk affect those choices. This dissertation has the goals of explaining how factors such as learning shape cost- associated decisions and how these decisions change according to individual factors. The first study focuses on tracking the development of discounting behavior as a function of delay and probability. Comparing the development of these behaviors across cost types reveal specific adaptations to different cost types in both sexes. Females were more sensitive to order effects than males. Overall learning of these tasks was well tracked by choice variability, even when discounting value estimations were unstable. The second study reveals how a copy number variant associated with neurodevelopmental disorders affects sensitivity to delay and probability in a sex- biased manner. Delay induced greater large reward preference in male carriers compared to noncarriers, but probabilistic risk instead induced small reward preference in male carriers. Male carriers in particular use environmental cues more than noncarriers to control behavior when rewards are delayed, but not when rewards are risky. These results highlight how this copy number variant affects choice according to uncertainty. Taken together, these studies reveal how sex and sources of neurodiversity contribute to decision-making.